A Field Guide to Joint Disease in Archaelogy - J. Rogers and T. Waldron OCR Reduit

A Field Guide to Joint Disease in Archaeology


JULIET ROGERS University of Bristol, UK

TONY WALDRON Institute of Archaeology, London, UK

J IN Wl Y & SONS c l il t IH .. :II 'r • N!'W Yorl • ll ri : h:11H· • Toronto • Si ngaporP

Copyright © 1995 by John Wiley & Sons Ltd, Baffins Lane, Chichester, West Sussex P019 1UD, England

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Libran; of Congress Cataloging-in-Publication Data

Rog rs, Juliet. A field guide to joint disease in archaeology I Juliet Rogers, Tony Waldron.

p. cm. In hides bibliographical references and index. I BN 0-471-95506-X 1. Joints - Diseases. 2. Paleopathology. I. Waldron, T. (Tony)

II. Title. [DNLM: 1. Joint Diseases - pathology. 2. Paleopathology. WE 300

R727f 1994] R134.8.R64 1994 616.7'207-dc 20 DNLM/DLC for Library of Congress

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

ISBN 0-471-95506-X

Typeset in 11/13pt Palatino from authors' disks by Mayhew Typesetting, Rhayader, Powys Printed and bound in Great Britain by Biddies Ltd, Guildford and King's Lynn

94-45111 CIP

Contents

Preface

List of Abbreviations

1. The Definition of Joint Disease

2. The Palaeopathological Classification of Disease

3. Osteophytes

4. Osteoarthritis

5. Diffuse Idiopathic Skeletal Hyperostosis

6. Rheumatoid Arthritis

7. Ankylosing Spondylitis

8. Other Seronegative Spondlyoarthropathies

9. Gout

10. Infections Causing Joint Disease

11 . Implications for Archaeologists

App ndix

C; •n rn 1 Bibliography

llttrll er R ·nd ing

vii

ix

1

8

20

32 47

55

64

69

78

87

97

108

111

112

11 5

Preface

I' tl tt·opathology is both exciting and intensely frustrating. The 1 t ·i I •ment stems from the fact that of all those interested in the li e• of our remote ancestors, palaeopathologists and archaeol-"1', 11-1 come nearest to them by handling what remains of their 1 d 1 1-1 i al presence. They can come literally face-to-face with I hn 1.' who lived centuries ago and it really is a privilege and a 1 tl c•111H tr to try to find out as much as one possibly can about II H•Il l. lt is wanting to do just this, however, which provokes 11 11 • f' rttstration because the amount of information which can be ' lt'lll t d from human bones is not great, and certainly not as I' 11 ' If , many archaeologists would like it to be, or many utlhl'opologists assert it to be.

l11 tddili n to general details such as age, sex and height about lite • individuals they have recovered, archaeologists would like 111 I· now what diseases the individuals suffered from, what they ol ••e l of, what their occupation was, what their state of nutrition

• 1 1 1nd . much as possible about their way of life, and the l11 dth of 1+1 population of which they were once a part. It is ol ' 11 1 d to hav to say that, in actual fact, very little such tile" 111 I! ion iH going t b - forthcoming, and we have the dis-

llrH I "IIH'<' ion t·h. t. gr nt many bon reports are a profound dt tppninlnwnl In lh ·ir r• il i •r tR.

111 cl 11 lite • lw I I l l!' t' 111 , 111 1 H•opn lhologil-l l l-l OWl.' it t·o then -' I •e• 1 rnd In Iilo .t• w1 who t • ht•ludf ll w wo rl , to do wh.1t

viii Preface

they can do well. They do this best by not exaggerating the claims for their discipline, and by ensuring that the information they do provide is soundly based and conforms to generally accepted clinical notions of disease. Although one does not necessarily have to have a medical education to undertake palaeopathological work it can certainly be an advantage, if only because one is thereby imbued with a sense of the unpre-dictability of disease, the uncertainty of diagnosis, and some concepts of pathological processes.

One of the important ways in which the palaeopathologist can provide information about the health of past populations is by describing the frequency of diseases over time, and suggesting ways in which environmental and other influences may have affected such changes as are seen. To do this, however, requires that the diagnostic criteria which are used are reliable and consistent, and it is to suggest some ways in which these objectives can be met that this book was written. We hav concentrated on the joint diseases because these are by far th most commonly found in human skeletal remains, and becau they have been our field of special study for a number of year . We had non-medical bone specialists particularly in mind and hope that the book will encourage them to be circumspect in their conclusions.

Over the years we have had much help and encouragem nl from our colleagues, clinical and archaeological, and we would like to thank them all. In particular, however, we would lik to thank Professor Paul Dieppe and Dr lain Watt, who have b en willing and valuable colleagues and collaborators over tht • years and who have guided our feet into the paths of rheumn to logical righteousness on many an occasion. We would a I t' like to take the opportunity to thank the medical illu trat r 11 Bristol for their enormous help with the photograph and otlwr• illustrations.

Juli 't Rogt•r· Tony Wnldwn

13ris/'ol nnd I .o11tloll, I 1)%

List of Abbreviations

•, ankylosing spondylitis

Ill ' ill diffuse idiopathic skeletal hyperostosis

I 111 ' I i tal interphalangeal (joint)

11 '1' m tatarsophalangeal (joint)

• r; ost oarthritis

1 11 l ost ochondritis dissecans

I 'I I proximal interphalangeal (joint)

I 'I

1'1

l P

1 soriatic arthropathy

rh umatoid arthritis

rheumatoid factor

1 The Definition of Joint

Disease

joints are the organs which form the junction between different I 1ones and in skeletal material are most frequently the site of pn thological change. As well as the two bone ends, joints have n l'lubstantial soft tissue component which can also be involved

11 joint disease; however, evidence for this can only be inferred I mm the bone.

'I 'here are three types of joint:

( I) fibrous, such as the sutural junction between the bones of the skull;

(: ) artilaginous, of which the symphysis pubis is one of the f w examples; and

('I) synovial, which forms the majority of those in the skeleton, in luding the hip, knee and apophyseal joints of the spine.

'l'ht• Hlructure of synovial joints differs fundamentally from the ni l wr lypes to allow free motion between the bone ends. The I H 1111 • , r joined by a fibrous capsule. The ends of the bones, lht• ll'li ulntions, are covered with cartilage which is lubricated lty llw Hy novinl fluid within the joint cavity, the synovial fluid lu• ng t·crd •d b ~h · Hynovial rn rnbran whi h )in th joint •' IV ly (H•t• Jligttt't• 1.1). 'l'ht· H novinl fluid iH. lso involv I in t·he tilili ' I Oil (]{' lht· tl'l it •td ill' (' lrlill)',i' ,

2 A Field Guide to joint Disease in Archaeology

BONE

CAPSULE

SYNOVIUM ---

JOINT SPACE ---

HYALINE ARTICULAR -----J

CARTILAGE

Figure 1.1

SKIN AND SUBCUTANEOUS TISSUE

BURSA

ENTHESIS

TENDON

LIGAMENTOUS THICKENING OF THE MUSCLE

Diagram of a typical synovial joint

Any, or all these structures, as well as the ligaments inserting into the joint capsule and the juxta-articular areas can become diseased. The type of disease present in a joint depends upon which of these tissues is mainly affected and which disease process is involved-such as inflammation or infection. These factors will determine which particular signs may be present on the bony elements of the joints. Many different types of joint disease have been recognised and described, not all involving the bones; the causes of some are unknown.

There have been many different classifications of joint disease through the ages, depending on the contemporary concepts of disease and on the investigative techniques which were th n available. Until relatively recently all classification of di al5 has depended on the clinical skill of the phy i ian nnd wl n t could be l arn d fTom obs ·rving, H t ning to or x. mlnl r g lhv

The Definition of joint Disease 3

p tient and his or her body fluids, and finally, on the results of post-mortem examination.

The earliest classification of joint disease was into acute and , ·hronic arthritis depending on the observed differences in the progress of the disease under consideration. A few of the early clinical descriptions are very precise and enable us still to r •cognise the disease being described; gout is one such 1•xample. The term gout, however, was used to refer to other conditions not now recognised as gout.

lr 1 the seventeenth and eighteenth centuries the advent of the rnicroscope introduced a further dimension into the under-1 I mding of joint disease. For instance, urate crystals were then 'll•ntified from the tophi (swellings) found in patients with

11out. The introduction of X-rays in 1895 quickly allowed the P pansion of the classification of joint disease using the results obtained from their radiographic examination. By looking for ll ll' first time directly at the bony changes involved in live 1 "1 Licnts it was seen that there were two main categories of joint pn thology and that these coincided with two types of joint 1l h; •ase. The first was termed atrophic; it affected younger 1 "•ople and many joints were involved and there was a l••nd ncy to inflammation of the soft tissues of the joint with • • r ·o~:~ion of the joint margins and loss of bone density. The

1 •cond type recognised radiographically was termed hyper-lt'OJ hie joint disease because of the hypertrophy or overgrowth , ,( marginal and articular bone manifested by osteophytosis and , ll•r sis. Pathological examination revealed a focal loss of

1 u·Uiage and this second set of changes tended to occur in older p1•op l and to affect fewer joints than the atrophic variety of tl'lhri tis.

11 Wnl' sub equent to these first X-ray classifications that Garrod 11 1904 all d the atrophic, erosive form rheumatoid arthritis

(I' A) n nd the hypertrophic form, osteoarthritis (OA). Some nllwr j' roups f ro iv arthropathy, formerly included within llw Jl' ' l rum of RA l av sin b n r lassifi d as parat l 'tll t it•ll in 1'1 Pir owr rigl t, th • rnoRt irnportnnt 111tt di vision lu • 111; lh 11 o l i lt' t~o cnll <·d t•t'<HH'g 1tlv<• HJ ond lo l l' lht·opn LI it• Wh t•l! W l ' l 'l ' dt• f l ll ' d I) fi ll' 11)(,()1 ,


It is thus clear that the manner in which diseases are classified depends partly on the set of examinations that can be made and how these are interpreted, and partly on the current concept of the disease process. However, there is always a tendency for observations to be made to fit the original concept of the disease. This has an important bearing on the way in which we attempt to classify joint disease in skeletal material because the majority of information on which clinicians may base their diagnostic criteria is absent. Thus, there is no living patient from whom to take a history or to examine, and no soft tissue for pathological or biochemical examination. The palaeo-pathologist's investigations are limited to the bony changes only, and in some joint diseases these may be minimal. The only routine investigation available is some form of radiology although it is possible that biochemical and immunological analyses will become available in the near future.

Bone reacts in a restricted number of ways so that the final pathological appearances of a joint in the skeleton may be the end result of any one of a number of diseases. However, the propensity for these bony changes to be distributed both within the joints and around the skeleton in a distinct and sometimes specific manner helps in many cases to clarify which particular joint disease has caused the skeletal changes.

The criteria which are for palaeopathological diagnosis are distinct from but related to strictly clinical criteria (Figure 1.2a and b). They are based on a visual assessment of the mor-phology of the bones with special note being made of the distribution and type of bone change within the joints and the distribution of the affected joints around the skeleton. There are characteristic patterns typical of certain diseases which can allow a reasonable chance of classification in typical cases. It is important to remember that typical changes will not be found in all cases, however (Figures 1.3 & 1.4). In clinical practice a disease evolves and a diagnosis may not be possible until it has progressed to a relatively advanced stage and clinicians hav many opportunities to review the changes in their pati nts. fn any one skeleton it is impossible to tell how Ion th dis a:,;' has been present or when during th di as th ind ividua l d i d. Mor ov r, th bony hang s di. I, y 'd on tlw ·kl' II'IOn

(a)

(I>)

The Defin ition of joint Disease

CLINICAL

RADIOLOGICAL

CLINICAL

PALAEO-PATHOLOGICAL

5

I Hllr• 1. ' (.1) Vnnn dl.1gr.ui1 of l'ti latlonship b tw n v;Jriou lini <I diagnost·i 1 illl tin (11) I ol.lllilll'•il p hntwn<'ll p.li.H'Opnthologlcal and r llnl ·<d ell. p,nn. tl ·

n Ill rl.,


OA uncommon.:: ..... .

OA········ RA•;J.i.~·:· . OA-... .'.'.

Psoriatic_...,...

RA ........ . Psoriatic ........ ... ·.

........ RA I atlanto-axial l OA C/4/5

DISH

...... ...... RA & OA

............ RA

.. ........... OA/Gout

Figure 1.3 Pattern of characteristic skeletal involvement in various arthropathies

may be from an early or a late stage of the disease.

In the following chapters, the main categories of joint disease that can be expected in the skeleton are discussed and we describe how they can be usefully diagnosed or classified in earlier skeletal populations.

NORMAL

RA

marginal

ADVANCED PSORIATIC

ARTHROPATHY

cup & pencil deformity

The Definition of joint Disease OA

sclerosis of "~··A~;;;~--"""""= I eburnation I

osteophyte

GOUT

bone noc>K··· .... fl

pararticular · erosion

ANKYLOSIS occasional feature

of Psoriatic/Reiters or AS of

peripheral joints

NEVER In RA

l lgure 1.4 Characteristic peripheral joint changes in various arthropathies

7

2 The Palaeopathological

Classification of Disease

In normal living bone there is a dynamic equilibrium between the cells that make bone (the osteoblasts) and those which resorb it (the osteoclasts), and this serves to maintain the integrity of the skeleton. This equilibrium is disturbed in bone affected by disease, but since bone has only a limited capacity to react to disease processes, one may greatly oversimplify the outcome by saying that diseased bone is characterised by there being too much or too little present. The diseases which affect bone, however, rarely do so in isolation. For example, the joint diseases may not have their origin in the bone, but in the other tissues of the joints, the articular cartilage or the synovial membrane (see Figure 2.1), and it may be difficult to under-stand the changes seen in the skeleton unless some thought is also given to what is going on in the surrounding soft tissues.

Another general point which needs to be clearly understood is that diseases may affect the skeleton in a selective manner. Thus in some joint diseases the distal interphalangeal joints (DIP) will be found to be involved, whereas in others it will be the proximal interphalangeal (PIP) joints; one arthropathy will present with multiple symmetrical changes, another with a lesion affecting only a single joint. Because of this, the more complete the skeleton, the better the chance of b ing r hably able to classify the disea es whi h ar pr s nt. Th nvcrs of

Figure 2.1

The Palaeopathological Classification of Disease 9

AREA OF CHANGE

JOINT MARGIN

ARTICULAR SURFACE

PERIARTICULAR

JUXTA-ARTICULAR

Diagram of a typical synovial joint showing areas in which pathological changes may be observed

this is obviously also true; and our advice, especially to the beginner is, if there is not much bone, do not say much about it.

FIRST STEPS IN CLASSIFICATION

The first step in classifying joint diseases must be to make an inventory of all the bones which are present in the well washed skeleton and note which joints are present. The \!Se of fixatives, which might impart a shine to the joints should be noted; and occasionally archaeologists or finds assistants will write the skeleton number on the joint surface; this is a practice strongly to be discouraged. If, as sometimes happens, the age and sex of the skeleton are to be determined by another worker you should agree criteria in advance if only to ensure that joint hanges are not used as an ageing criterion, since if they are,

1 otentially useful epidemiological information will be lost.

It is essential to use forms devised specially for recording 1 urposes and not rely on free-form notes otherwise details will in vitably b mis ed off. An example of the recording forms whi I w · ro11fi1 ' 'Y us ar hown in the app ndix. The joint lnvt·nlor l lll't 't 't nr w l t'n on~o; id <' rinr th pa l t rn of joint

1 0 A Field Guide to joint Disease in Archaeology

involvement and for providing the denominator data for subsequent epidemiological analyses (see below).

Having recorded these details, the skeleton is carefully examined for abnormalities. The position of joint lesions should be recorded on a skeletal diagram from both the anterior and posterior view; in the spine, the level of each lesion should be recorded and, in the case of the facet joints, the side or sides affected. It may be useful to make a more detailed record of some of the individual joints; for example, we routinely use separate charts for the hands and feet and for the shoulder, hips and knee, but there is no reason why others should not be used if required. When collecting data for research purposes, rather than for routine bone reporting, con-siderably more information is likely to be required and when deciding on the level of data to record, bear in mind the possibility of further studies; also bear in mind that it may not be feasible to go back to re-examine individual skeletons again, especially if they are to be reburied, and that yours may be the definitive set of observations made on a particular group of skeletons. Obviously a balance has to be struck between what is practicable to record, given the constraints of time and money, and what one might wish to preserve for posterity.

When preparing diagrams of lesions it is helpful to show different features in separate colours: red for proliferation, blue for erosions, green for eburnation and so on, as in this way the patterns of change throughout the skeleton are much more easily detected. Some work has been started in the United States to computerise skeletal diagrams, and when this has finally been achieved it should be possible to use computer-aided classification; but this is still some way off. Nevertheless, with any but the smallest site the data relating to joint numbers and some form of coding for the pathology present will have to be entered into a database the precise nature of which will almost certainly be a matter of personal preference.

In addition to the systematic recording of the sites and distri-bution of lesions, a clear and detailed description should also be made, especially as not all lesions will fall into a p i fi category. Photographs hould b tak n and illu tr::~t ionA m. tk


wherever possible; this is especially important if the skeletons are to be reburied or cremated.

EROSION AND PROLIFERATION

We have said that bone has only a limited capacity to express pathological change; it may gain substance through the proliferation of new bone and it may lose it in the form of erosions which are manifestations of osteoclastic activity or sometimes the result of direct pressure from adjacent soft tissues or abscess cavities.

During the examination of the skeleton, each lesion which is found should be assessed to decide whether it is erosive or proliferative, or, as not infrequently happens, a combination of both. It will also be necessary to record the presence of other abnormalities affecting the joints of which the most important in the present context is eburnation.

Proliferation

Detecting the presence of new bone around a joint margin or on the surface of a joint is relatively straightforward although it may be difficult sometimes to determine whether minimal change is within the spectrum of . normality or not, remem-bering that there is no abrupt change from normal to abnormal, and only experience will help on this point. Some workers like to grade the changes which they see on a simple three- or four-point scale and this may be useful. However, if you decide to do so, remember that your gradings will probably not bear much relationship to those of another worker in the field unless rt'f r nee can be made to type specimens; and there is also lik ly to b a ood d al of inconsistency in grading from day to dny (Ace . IAo h. pl:l'r 3 on ost phyt . f r furth r d tails on w ring nw t hod ).


Erosions

As used here, the term erosion applies only to pathological lesions in or around joints. The term is often more widely applied to post-mortem damage around joints or on the bone surface. We would prefer that the term 'erosion' is restricted to the lesions accompanying joint disease and that other terms such as abrasion be used for post-mortem damage.

Erosions can present much more of a problem diagnostically than proliferation, and they must be carefully distinguished from post-mortem damage and from the other holes which may be found around the joint. These other holes may include vascular foramina, cysts and canals produced by roots or fungal hyphae. There is no simple way to discriminate true erosions from other holes around joints but there are some pointers. For example, in a true erosion the cortical bone is lost and the underlying trabeculae may be exposed and under the scanning electron microscope, signs of osteoclastic activity may be seen (Figure 2.2). Any hole in which the cortex is completely intact (such as the entry site for a nutrient artery) is not an erosion, although you must remember that there will be an attempt at repair and some remodelling may be present in a true erosion. Differentiating post-mortem damage from a true erosion usually presents a greater difficulty, but post-mortem damage is seldom symmetrical and may extend well beyond the confines of the joint. Damage sustained during or after excavation may have fresh edges but even this is not an infallible distinction, however, as some erosive arthropathies are accompanied by osteoporosis, which makes the bone more fragile and more easily damaged during handling. In some erosions there is an undercut edge which is not usually present in an artefactual lesion.

The lesions in some of the joint diseases start at the joint margin, in others in the centre of the joint and in others outside the joint capsule; if it is possible to make this distinction it can help with the classification, but in many cases the disease will be too advanced or the bone too damaged to p rmit su h an observation.


Figure 2.2 Electron micrograph showing in vitro osteoclastic activity. (Courtesy of Dr Adrianne Flannigan)

Eburnation

Eburnation is an important feature in joint disease since it is pathognomonic of OA. It manifests itself in dry bones by highly polished areas on the joint surface and is caused by an area of bare bone moving over other structures. Eburnation is almost always found on the reciprocal surfaces of a joint, although this is not necessarily the case. Eburnation is never found in a joint which has been immobile. There is generally no excuse to miss 'burnation, although small areas on, say, a distal phalanx may not be seen unless the bones are examined in a good light as I hey always should be.

Osteoporosis

< )Hit'op<H"OHi. · iH lh' loHA of bote Hubstc n resulling in orti al thhmi11p, or 1 d1•cn• Hil' in llw lltllllht·r· of lrnl t·rtllnt·. 11 iH •


secondary sign of some joint diseases and can be suspected if a bone feels unduly light but can only be confirmed by radiography.

Compound joints

Some joints, such as the elbow and the knee, consist of more than one anatomical compartment-in both the elbow and the knee there are three-and these are known as compound joints. Changes found in such joints should be recorded for each compartment, and for epidemiological purposes it is legitimate to consider each compartment separately (see Chapter 4). Some complicated systems for scoring these joints have been described in which each compartment is considered to be a fraction of a joint and a score is assigned to the joint depending on how many 'fractions' are involved. This kind of scoring system has no clinical correlates and should be completely avoided unless a special research topic is being pursued. For epidemiological purposes, the rule should be that a compound joint is treated as a single joint, although its compartments may be treated separately in any subsequent analyses.

SUPPLEMENTARY EXAMINATIONS

There are relatively few supplementary examinations that are of value to the bone specialist and the only one which is used frequently is radiography. Radiography is most likely to be helpful with the classification of the erosive arthropathies and we would go so far as to say that under normal circumstances there is no virtue in X-raying joints with OA since little further information is likely to emerge which would cause you to change your classification, assuming that the proper procedures have been followed in the first place. The advice of an experi-enced skeletal radiologist is absolutely essential in drawing conclusions from the films which are taken.

The Palaeopathological Classification of Disease 1 r.

CLASSIFYING INTO MOST PROBABLE CAUSE

Having recorded all the lesions and noted their character and distribution, the next step is to classify these changes into their most probable cause; for the joint diseases which are most likely to be found in skeletal material this procedure is described in the following chapters.

It is often intensely frustrating trying to classify joint lesions since, with the exception of eburnation in OA, there are no pathognomonic signs and so often critically important parts of the skeleton are missing. You will probably find that in a substantial number of cases you are able to do no more than note that you are dealing with an erosive arthropathy of some kind and will have to admit that further classification has defeated you. You may take some comfort, however, from knowing that your clinical counterparts may not be doing a great deal better even with their ability to interrogate their patients and their access to a large array of investigations. Moreover, clinicians have an opportunity to see disease in 'volution, and see it as a changing, dynamic process. Palaeo-pathologists, by contrast, have only one view of disease in their 1-mbjects and that at a most unfortunate time for them, the time of their death. There is no telling where in the progress of the lisease the subjects were and the appearances may or may not 'Onform to modem textbook appearances; it is just a matter of chance.

DETERMINING THE FREQUENCY OF DISEASE

Reporting on disease in the skeleton can take one of two forms: the case report or the population model. Case reports, where I h number of subjects is small- perhaps even a single case--I r often used when dealing with rare or unusual diseases but I h ·y provide no useful information about the frequency of 'llRcas in pa t populations. If this is the aim, then population d tn hnv to b u A d and "om stimate of th frequ ncy of tb dit-~(' 1 'C' ondN con 'idNnllon hn to b mod ; this is o hi •v<>d y 1 tll'!tllling lr jH't •y tlt •t)l 't ' ,

I() A Fi Id Guide to joint Disease in Archaeology

The prevalence of a disease is expressed simply as the ratio of the number of those with the disease to the total population; that is

where P = prevalence,

p = .!!__ N

n = the number of cases with the disease, and N = the total population.

You may see the frequency of a disease in skeletal populations referred to as an 'incidence' or an 'incidence rate'; epidemio-logically this is incorrect for reasons which are gone into more fully elsewhere; suffice it to say, incidence should never be used when referring to the frequency of a disease in a skeleton population. ·

As it is a simple ratio, the prevalence of a disease is strictly speaking not a rate, but the term 'prevalence rate' is often used as the normal expression. Whether the correct or incorrect term is used, however, prevalence is almost never given as a percentage but depending on the size of the base population (the denominator), as so many cases per 103 -106; the size of skeletal populations would generally preclude referring to a base population greater than a thousand.

CALCULATION OF PREVALENCE

In contemporary populations the calculation of prevalence is an extremely straightforward exercise-in so far as anything is simple in epidemiology; just count the number of cases, the number in the base population and divide the first by the second. When trying to carry out this elementary aritlunetic on skeletal populations, one very soon comes across a diffi ulty which relates to the number to put in th d nomi:nat r; in other words, what is th population?

The Palaeopathological Classification of Disease 1 7

onsider for a moment a simple example. You have a group of 175 skeletons and you find that nine have OA of the hip. The apparent prevalence of this condition is 9/175 = 51.4/103

; this i referred to as the crude prevalence. Suppose, however, that 26 of the skeletons are so badly damaged that they have no hip joints, then it is clear that they should not appear in the denominator and the prevalence now can be calculated as 9/{175-26) = 60.4/103 . However, there is yet a further compli-ation to consider befpre one can let the matter finally rest. We

now have 149 skeletons with hip joints, but what if 13 of these have only one normal joint present? We know nothing about the Htatus of the missing joint-it might have been either diseased or normal, but as we do not know, we are obliged to exclude lhese 13 from the denominator and so the final calculation becomes 9/{149-13) = 6.2/103

. (It should be noted that this 1 rocedure can be somewhat simplified by considering the left nnd right joints separately, but this would be an unusual •pidemiological practice.)

What should be remembered from this exercise is that the total number of skeletons in a group may not be the appropriate denominator when calculating the prevalence of joint disease; nlmost never in the case of OA, which is far and away the most 'Ommon disease seen in the skeleton, and this is why it is so vital to have an accurate inventory of the number of joints 1 resent.

AGE- AND SEX-SPECIFIC PREVALENCE

Prevalence can be calculated for the different sexes and for different age classes, in which case one refers to sex-specific and nge-specific prevalence, respectively. It would generally not be worthwhile to do this with the less common joint diseases but it · •rtainly is when dealing with OA and if, for example you were lo find th t th pr val ne of OA did not increase considerably wi lh ngl 11 mi)"ht ho s tor vi w th ag s allo at d to your

(' (i'IOIIH,


COMPARING PREVALENCE IN DIFFERENT SKELETAL GROUPS

One reason to study skeletons is to compare the frequency of disease in different groups and investigate whether variations in frequency may be related to environmental, social or other factors. Comparisons such as this will be made using the prevalence of the disease but, if the crude prevalence is used, like may not always be compared with like, and the reason for this lies in the fact that the age structure of different popu-lations may be dissimilar. This point can be illustrated simply by considering a disease where the prevalence is highly age-related; OA or diffuse idiopathic skeletal hyperostosis (DISH; see Chapter 5) would be good examples.

Imagine we have two skeletal populations (A and B) each of 350 individuals. In A there are 19 cases of a disease in which we are interested, whereas in B there are 46. The apparent prevalences of the disease in A and Bare 19/350 and 46/ 350 = 54.3 and 131.4/ 103 respectively; these are known as the crude prevalences. It appears that the disease is almost 2lh times more common in B than in A. When we look at the age-specific prevalences, however, there is an anomaly as the age-specific prevalences are identical in both populations; see Table 2.1. The reason for the apparent excess in B is that there are more older individuals in this population, in whom the disease is much more frequent, than in A, where young individuals with a low prevalence predominate. By comparing the age-specific prevalences it is clear that the frequency of the disease is exactly similar in the two populations.

Table 2.1 Age-specific prevalence of disease in two populations

A

Age-group n N P/103

25-34 4 200 20 35-44 5 100 50 45+ 10 50 200 Total 19 350 54.3 n = number of inviduals with the disease N = tota.l number in age-group P = pr •va lcn c

B

n N P/103

1 50 20 5 100 50

40 200 200 46 350 1 1.4


It is perfectly respectable to compare age-specific prevalence between populations using appropriate techniques, including that of comparing odds or risk ratios. One can also use the so-called method of direct standardisation. Any of these methods can produce a summary statistic which can be compared between populations. You should be aware of how these procedures are carried out but this is not within the remit of the present book and we must refer you elsewhere.

3 Osteophytes

Osteophytes are growths of new bone which arise round the margins of a joint and which may vary considerably in size and shape. They are extremely common in any skeletal population and their prevalence increases markedly with age, and almost any skeleton over the age of 50 or so will be found to have osteo-phytes around at least one joint if examined carefully enough.

DISTRIBUTION

Osteophytes may be found around any joint but they appear around some more commonly than others. For example, they occur round the knee and hip joints more often than around the ankle, around the DIP joints more frequently than the PIP joints. They are especially common around the margins of the vertebral bodies but are found more often in the cervical and lumbar vertebra regions than in the thoracic. Osteophytes are also commonly seen around the margins of the facet joints of the spine and, especially in older individuals, on the odontoid peg.

MORPHOLOGY

Osteophytes around joint generally tak th ir origin nt the point at whi h th . ynov ia'l m mbrnr is onlinuot tH wi th llw

Osteophytes 21

articular cartilage, that is, at the joint margins. On occasion the osteophyte forms a complete ring around the joint, demarcating it exactly from the surrounding normal bone and a normal joint tourface. The degree of bone formation can vary enormously from a minute rim to an massive outgrowth which may some-times form a phlange several millimetres deep around the joint. Large osteophytes are likely to be seen especially around the margins of a concave joint such as the acetabulum or the glenoid; very rarely we have seen the head of a femur so nclosed by osteophytes arising from the acetabulum that the

two could not be separated.

In the spine, osteophytes on the vertebral bodies are somewhat different from those in other sites (Figure 3.1) in that they take their origin from the point of attachment of the fibres of the , nnulus fibrosa. Osteophytes here tend to develop horizontally, I ut may turn vertically if they become sufficiently large (Figure ~ . 2).

,' ince there is such variation in the degree of osteophytosis nround joints, some workers have devised rating scales to r cord its presence. These usually have three or four points, nnd individual joints are rated either as 0, when no osteophyte is present, or from 1 to 3 (or 4) when it is, depending on the ize and extent of the new bone formation. These scales may

1 rovide useful information for individual observers but they 11 re not particularly helpful for interstudy comparisons as it is t mlikely that there will be a high level of concordance between 1 he ratings of different observers since they reflect qualitative rather than quantitative differences. The discrepancies are noted 1 articularly with specimens which are considered to be 'borderline' between the categories and many observers experi-t•nce a problem with knowing exactly when to rate minimal change as being of significance, that is, worthy of inclusion into I h lowest category. Rating scales are sometimes used to rn. asure the 'severity' of the degree of osteophytosis present, but this concept has very little meaning since it implies that the OHt phytes may have impaired the individual to lesser or gr '( t r d gr s during life and there is no evidence that this is rdua lly th as . It is b tter not to use rating scales in this way 111d tlwr~· 114 g~'n<'n ll r ot much to omm-nd th ir use at all,


NORMAL

DISH or

Forrestiers Disease

huge paravertebral

• •

bone extensions \:'::::::::::::::::::::::::::::::::::::::::::::::::

ANKYLOSING SPONDYLITIS

squaring of corners of vertebrae · ··· · ··r~='""""'==~

OSTEOPHYTOSIS

Figure 3.1 Characteristic changes in the vertebral bodies in some spinal diseases

except where some particular research interest is being pursued.

OSTEOPHYTES AT OTHER SITES

Osteophytes occur at sites other than around joint margins and although their significance is outside the scope of the present book, it is, nevertheless, worth giving them a passing mention. They may occur on joint surfaces, appearing as flat, irr !lady hap d plaqu · of bon u ually in a"' o iation with mnrginnl

Osteophytes 23

Figure 3.2 Spinal osteophytosis

osteophyte. They may or may not be associated with OA. They are not often referred to clinically as they do not usually show up on an X-ray.

Growths of new bone may also be found elsewhere on the skeleton and are often associated with injury as it is assumed t-hat they represent the calcification or ossification of hae-matomas. For example, fractured ribs may be found joined by thin bands of bone that can be interpreted to be the results of ossification of a bleed which occurred at the time of the fracture. These growths of new bone are sometimes referred to lS osteophytes, but ought more correctly to be called exostoses. Occasionally large, curiously shaped exostoses may be found 1 rising from the shafts of long bones-the femur seems often to I) • involved-and these are considered to be ossification into bleeds that have taken place into the body of a muscle which was damaged by some unusually strenuous exertion. This mndition is frequently referred to as myositis ossificans but tHtght p rhaps to be qualified as myositis ossificans traumatica lo diff r nti t it clearly from the rare, hereditary condition, 111 oHi liH (or fibrodyspla ia) o sifi ans progr s iva. Th ·


Table 3.1 Types of bony outgrowth in the spine

Type of outgrowth Morphology Associated with

Ossification of annulus fibrosa (syndesmophyte)

Osteophyte

Anterior ossification

Vertical outgrowth extending from the edge of adjacent vertebral bodies Horizontal outgrowth from edge of vertebral body Flowing growth along anterior border of the spine into the anterior longitudinal ligament

Paravertebral ossification Outgrowth of bone separated from the edge of the vertebral body and the intervertebral disc

Ankylosing spondylitis

Degenerative disc disease

DISH

Psoriatic arthropathy Reiter's syndrome

exostoses are sometimes considered to be indicators of occu-pational stress or injury. In the spine, bony outgrowths may be seen as a result of ossification of the annulus fibrosa of the intervertebral disc, as a longitudinal, flowing ossification into the anterior longitudinal ligament, intervertebral disc and the paravertebral connective tissue, and as ossification of the paravertebral tissues alone. These are all generally referred to as osteophytes and although some authorities might object to this usage, it is so ingrained in the literature that it would be perverse to try to change it. The characteristics of these different types of spinal bony outgrowths and some of their causes are shown in Table 3.1.

Enthesophytes

Osteophytes may also be seen at the site of tendon insertion~, the area known as the enthesis; the preferred term for them IS enthesophytes (Figure 3.3). They may re ult from r p at d trauma to t ndon ons qu nt 11pon r p t d • u R ul. r <· N I ion

Osteophytes 25

Figure 3.3 Enthesophyte on olecranon process of the ulna at the point of insertion of the triceps muscle

but they are also found as a concomitant of other diseases and, again, their interpretation as indicators of occupation or activity needs carefully to be qualified; this is discussed further in Chapter 11.

SIGNIFICANCE OF OSTEOPHYTES

There is no difficulty in recognising the presence of osteophytes in the skeleton and there are no diagnostic problems in that respect. The question is to what extent do they represent disease in the skeleton? In the absence of any other · abnormali-ties in the skeleton, then marginal osteophytes are probably not pathological. Indeed, they appear to be a normal accompani-ment of ageing; the prevalence of osteophytosis increases markedly with age and in some joints-the spine and the hip, for example-they appear to be independent of other signs of OA. Because their frequency increases with age there is a lt·mptation to use the presence of osteophytes as a means of ng ing; this is at best an imprecise method and we would not Hlvo at its u e. If one is trying to study the age-specific


Table 3.2 Some conditions associated with osteophytosis or new bone formation

Ageing Osteoarthritis Intervertebral disc disease DISH Trauma Ankylosing spondylitis Psoriatic arthropathy Reiter's syndrome Acromegaly Fluorosis Ochronosis Neuroarthropathy

prevalence of osteophytes then their presence is absolutely contra-indicated as an ageing technique.

OA is by far the most common condition in which osteophytes are seen and they are one of the minor criteria for classifying this disorder (see Chapter 4) but they may be seen in many other conditions, some of which are shown in Table 3.2. The conditions are listed in probable order in which they might be expected to be found in the skeleton and none but the first five is at all common.

Although they are common in OA, osteophytes must not form the basis of the palaeopathological diagnosis if there are no other signs such as eburnation, new bone on the joint surface, pitting on the joint surface or change in joint contour. Although the presence of osteophytes around a joint is used radio-logically to diagnose OA, there is no justification for doing so in palaeopathology and those who use this as the sole criterion for classifying OA in the skeleton are in error.

DEGENERATIVE DISC DISEASE AND SCHMORL'S NODES

These conditions are so common in the skeleton and so oft n associated with osteophytes that this ms an appropri. t pla to consid r th m.

Osteophytes 27

Degenerative disc disease

Degenerative, or intervertebral disc disease is diagnosed by coarse pitting, sometimes associated with new bone growth, on the superior or inferior surfaces of the vertebral bodies (Figure 3.4). It is most commonly found in the mid- and lower cervical, upper thoracic and lower lumbar regions of the spine and may be on one or both surfaces of an individual vertebra. Marginal osteophytosis is an almost invariable accompaniment and these changes are presumed to reflect degeneration in the inter-vertebral disc. In some cases osteophyte may be observed encroaching on to the intervertebral foramen, through which the nerve roots leave the spinal cord, and in some instances the foramen is so narrowed that it seems likely that the nerve root must have been compressed during life. This is the course of events which gives rise to cervical spondylitis which is a condition commonly met with in clinical rheumatology or neurology.

Schmorl's nodes

These are recognised in the skeleton as indentations in the superior or anterior surfaces of the vertebra, and are most common in the lower thoracic and lumbar regions. They represent the herniation of material from the intervertebral disc through the end plate and they are pressure defects. They are often irregular in shape and have a lining of intact cortical bone and may be found in any position on the vertebra depending in which direction the disc has herniated. With posterior herniation the lesions may be found in communication with the spinal canal, and if anteriorly there may be some associated kyphosis and osteophytosis, in which case the condition is referred to as Scheuermann' s disease.

Osteophytosis and Schmorl' s nodes are both common con-ditions and so both are frequently found together. However, Lh re is no evidence that, with the exception noted above, they 1 r ausally r lated.


OSTEOCHONDRITIS DISSECANS AND METATARSAL PITTING

(

These conditions are seen commonly in association with osteophyte formation and will be considered here as they do not fit neatly into any other category.

Osteochondritis dissecans (OD)

OD is referred to quite often in the palaeopathological literature, but it is probably considerably overdiagnosed. The lesion is the result of fragmentation and probable disruption of articular cartilage probably consequent upon trauma. The result is a defect in subchondral bone which is generally in line with the long axis of the joint surface; the lesion is variable in size, shape and depth and may be surrounded by a rim of

(

osteophyte (Figures 3.4, 3.5 & 3.6). OD has a peak age of onset between the ages of 15 and 20, is more common in males than in females and is much more often unilateral than bilateral. It occurs only on

Figure 3.4 Characteristic changes of degenerative disc disease showing plll'lng and rough ning f th nd plat· s and som • ost·corhyto. ls

Osteophytes 29

Figure 3.5 Osteochondritis dissecans on the medial femoral condyle

Figure 3.6 Radiograph of specimen shown in Figure 3.5

other sites at which the condition occurs at all frequently are the humeral compartment of the humeroradial joint and on the dome of the talus.

D must be differentiated from small pits or other lesions whi h ar ornrnonly seen on the concave surfaces of joints and

10 A I i£ Id Guide to joint Disease in Archaeology

Figure 3.7 Pitting on inferior surface of third metatarsal and lateral cuneiform. Scale in cm

which have a different aetiology. Such pseudo lesions are frequently seen on the proximal joint surface of the first

( phalanx of the foot, for example, and David Burkitt referred to \ them as osteochondritis non-dissecans. It is all too easy to

record any defect on the joint surface as true OD and care should be taken not to perpetuate this error.

Metatarsal pitting

This is a curious condition in which fine pitting is seen on the \ reciprocal joint surfaces of the third metatarsal an~:Lthe 1 £1:91 \ Cl,J.neiform (Figure 3.7). The planta~o1,.oot ones may l:ie \ sligfit y enlarged and the pitting confined there, alternatively it

may cover the entire surface. The condition is generally bilateral and may be accompanied by marginal osteophyte. Its prevalence is variable; in some North American Indian populations it may be 10% or more but in this country it i

( much less common. The cause and ignifi an of it er cnlin'ly \ unknown.

Osteophytes 3 1

haracteristics of osteophytes

• growths of new bone around joint margins and at other sites

• vary in size . • increase in prevalence with age • commonly seen in osteoarthritis . • found in diffuse idiopathic skeletal hyperostosis. • cannot be used to diagnose osteoarthritis as an Isolated

finding . . • should not be used as an agemg technique

4 Osteoarthritis

OA is the commonest joint disease in both modem and ancient populations but was not well described until Heberden did so in the eighteenth century. It is characterised by a focal loss of articular cartilage and subsequent bony reaction of the subchondral and marginal bone.

OA affects only synovial joints and the prevalence of the disease increases markedly with age; in modem populations it tends to be more common in females than in males. In theory, any synovial joint can be affected by OA but, in practice, it

(

occurs in some much more commonly than in others. The major sites are thej:§lli!s (especially the joints around the trapezium), the facet joints of the ~t'lbra, the acromioclavicular joint, the first metatarsophalangeal (MTP) joint, the hip and the knee. Clinically, many patterns of OA have been described and it is now felt that there are a number of more or less distinct forms.

(

, For example, bilateral OA of the hip is thought to be a distinct entity and it tends to affect younger males. By contrast, generalised OA, in which the DIP joints of the hands, the thumb base and the knees are involved, is more often found in

, middle-aged women. Examination of skeletal material makes it obvious that there is a wide variation of joint involvement and much work has been done on localising this differential joint involvement in skeletal populations and equating the diff r-ences found to various activities and oc upatio:ns. B au th y hav the opportunity to xamin v ry joint in l'lw bod ,

Osteoarthriti · 'I I

palaeopathologists see OA in sites which the ~linici~n nd radiologist seldom, if ever, have ~rough~ to th:II notice. For xample, OA affecting the odontoid peg IS r~latively co~on

in skeletal populations but scarcely recogrused as a _clinical •ntity; other unusual sites at which OA ma~ ~e foun~ mclu~e the inter-metacarpal and inter-metatarsal JOmts. ~Ith the~r < bility to examine the articular system in mo~e detail than IS

ossible in a live population, palaeopathologiSts are able to ontribute substantially to our understanding of this disease.

The association of OA with the concept of wear and tear, or as degenerative disease, and hence the result of over-use

through activity or occupation is a long one and probably arose in the first place from observations on the focal nature of the loss of cartilage which occurs in the disease. However, our present understanding of the pathogenesis of OA sugg~sts a much less straightforward association. The changes seen m the artilage are not necessarily progressiv~ but represent real or

1ttempted repair, rather than degeneratlo~. OA IS probab~y the

1 roduct of a normal remodell~g ~r. repair ~r~cess ~nd IS the natural reaction of a synovial JOmt to JOmt failure. The nlteration of the mechanics of the joint, either through injury or , tivity is only one element in the process; the age,_ systemic md genetic predisposition of the in~ividual are ~lso Important factors in the development of the disease (see Figure 4.1). The mechanical element probably acts to determine which joints are involved in an otherwise predisposed individual.

EROSIVE OA

In a very few cases, erosions are noted in the ~te:rhala~geal joints in individuals with true OA. Erosive OA: IS differen~mted fmm the other erosive arthropathies as the lesiOns are articular m ther than marginal; on X-ray they produce a 'gull-wing' 'I pcarance (Figure 4.2). Althou?h once co~idered a separate 11 iHca e, erosive OA is now considered to be JUSt a severe stage of n rmal int r h. lnng al A. To the best of our knowle~ge, only on , s · I ~~~ o f 11· ppcar d in the palaeopatholog1cal I It ' 1'1 t1 ur·<·.

A Field Guide to joint Disease in Archaeology

Systemic factors ~

Genetic predisposition

Predisposition toOA

Local biomechanical

factors

Site & severity ofOA

Figure 4.1 Model of factors influencing the pathogenesis of osteoarthritis. (After Klippel & Dieppe)

OA IN ANIMALS

OA is common in animals and is probably the disease found most frequently in animal bones from archaeological sites. There is no difference in the pathology between species, although the rate of progress may be extremely rapid, especially in large animals. Some forms of OA in animals have particular names in the veterinary literature and archaeological bone specialists should perhaps be aware of them.

Ringbone

This refers to OA of the interphalangeal joints of ungulates, especially horses. It principally affects the joints of the forelimb. Th 'ringbone' is osteophyte which may ompletely n ir lt' th joint.

Osteoarthritis . 5

Figure 4.2 Radiograph of palaeopathological specimen showing typ_ical changes of erosive osteoarthritis with 'gull wing' of left second d1stal

interphalangeal joint

Spavin

This is OA of the tarsus of the horse and sometimes the ox. The disease usually begins first in the joint between the second and t·hird tarsal bones but may spread to involve all the joints.

PATHOLOGY

The initial pathological change in OA is fibrillation of the artilage, which may lead to complete degradation. Where this

h< ppens, the bony articular surfaces become bare and rub together forming a dense shiny surface which is referred to as 1•burnation (from the Latin eburnea, meaning ivory); this tends to ccur at the point of maximum mechanical loading of the joint. New bone is formed around the margin of the joint and it tfl, y 1 o b form d on the joint surface. This new bone n·1 r \ nts an att mpt f th joint to tabilise itself and although t i r of 'IT· I to HI-I Ol-!1('01 hytt•, it Rh ul b cliff r ntiated from

tlu· oHl!·oph lt• which i ottnd nroun th joints a a

](> A Field Guide to joint Disease in Archaeology

concomitant of ageing. In some forms of OA (so-called atrophi forms) the production of new bone may be minimal, but by contrast, it may be extremely florid in the hypertrophic form , especially if OA develops in association with a bone formin condition such as diffuse idiopathic skeletal hyperostosis (se Chapter 5).

Until recently some forms of hypertrophic OA have been considered as separate entities caused by the shedding of calcium pyrophosphate crystals into the joint; it was referred to as calcium pyrophosphate disease. This condition was also sometimes known as pseudo-gout in the clinical literature by analogy with true gout in which uric acid crystals precipitat the pathological process (see Chapter 9). However, most authorities include pyrophosphate arthropathy within th general spectrum of OA and believe that the presence of crystals within the joint is a post hoc rather than a propter hoc phenomenon.

If eburnation has occurred this is a sign that the articular cartilage has completely disappeared from the areas of bone contact and this is the pathognomonic sign that the joint ha been affected by OA. Sometimes the ebumated area is grooved or scored to a greater or lesser extent, the grooves usually running in the direction of movement of the joint (Figures 4.3 & 4.4). Some eburnated surfaces are also pitted, but pitting and porosity often occur in the absence of eburnation. Occasionally pitted areas on the joint surface are observed to overli . subchondral cysts on X-ray, but this is less often observed than other radiographic changes.

OA COMPLICATING OTHER DISEASES

Manifestation of osteoarthritic changes, in particular ebmna-tion, are frequently observed where a joint has been damag by other diseases or by trauma. For example, eburnation may be noted in an erosive arthropathy such as RA, wh nth join t has been disrupted so that the me hanics ar di tort . ;\ may also complicate an infectious ro ss or follow tr 111nn. Po t-traumatic OA m t y aris w h n I lw In H of • bonl' h 11 1 I u 'I' ll

1 11

ure 4.3 Osteoarthritis of the facet joint <?f a cervical ~~rtebra sho~i~g nhurnation and grooving. Marginal osteophytos1s and some p1ttmg on the JOint

surface are also evident

1 ,roken and healed in poor alignment; it is almost inevitab~e when a fracture line extends into a joint and is also common m 11 1 , knee following damage to the intra-~rticular ligam~nts and 111 ,nisei. OA may also occur when a jomt ha~ bee~ dislo~ated 1nd not reduced, in which case a new articulation will be formed (Figure 4.5).

RADIOLOGY OF OA

'l'h cardinal sign of OA on an X-ray is narrowin~ of the no~al joint space which is taken to represent loss of articular cartil~ge (Pigure 4.6). This sign is no help at all .to the pa~aeopa~holo?Ist, hut other less important signs can confirm the diagnosiS arnved

11 from visual inspection of the bones. The presence of 1•burnation is recognised radiologically by the _Presence of clerosi that is dense white subchondral bone (Figure 4.7a &

h) . In H~m a ' s, ub h ndral cysts may be seen _which may 1·on1111 unk. t<-' with 1 ltling 0 1 th surface. Changes m the bony

A n •Id Guide to joint Disease in Archaeology

Figure 4.4 Macerated post-mortem specimen with osteoarthritis of the patellofemoral joint showing extensive grooving and bony contour change with

marginal osteophytosis

contour of the joint may also be seen radiologically and these may occur in the absence of any change on the articular surface. The most extreme changes in bony contour tend to occur in the femoral head which may become flattened and widened to resemble a mushroom (Figure 4.8).

As with all palaeopathological material there is a considerabl disparity between the visual and the X-ray app aran s. Changes in the dry bone are much mor bvious in th fl si (so to speak) than on X-ray. n Htu :ly whi h wt- nrrh•d Ottl

Figure 4.5

Osteoarthritis

Dislocated glenohumeral joint showing original articulation and formation of new joint

t lgurc 4.6 R di graph fr m m d rn p.atient with characteristic changes. of 1,.,,1 o:uthri tl s. Not ' joint sp.tct n:mowlng 111 lat ra l ompartment, som~ margmal

ostl'ophyto Is and ~ ul whnnd r.t l sriNosis (in r a d ban d nstty)


(a) (b)

Figure 4.7 Archaeological specimen with osteoarthritis of the humeral head with (a) eburnation, pitting on the joint surface, change in bony contour and

marginal osteophyte; (b) subchondral sclerosis with marginal osteophyte

showed a great disparity between the frequency of OA when the same set of joints were assessed by a palaeopathologist (Juliet Rogers) and a radiologist. Depending on which criteria were used, the frequency of OA ranged from 2% to greater than 60% (see Table 4.1).

OA AT THE SHOULDER JOINT

OA of the glenohumeral joint is rare, but there are a number of patterns of what are still generally referred to as degenerative disease around the shoulder joint which are common, may lead to the development of eburnation and may be due to changes in the rotator cuff, which helps to stabilise the shoulder joint. So-called rotator cuff disease is common and incr ases markedly with age and it is possible to reco is a nttmlwr of patholo ical patt rn .

Osteoarthri tis "'

Figure 4.8 Mushroom-shaped femora l head

Table 4.1 Comparison of morphologica l and radiological appearance of 24 knee joints

Morphological appearance Radiological appearance

Normal Osteophyte only Osteoarthritis1 Osteoarthritis2

8 11 5 2 33.3% 41% 21% 8%

The appearances were judged by a _r~laeopathologist and a radiologist. Both Investigators agreed that eight of the 24 JOmts were normal. . 1 Based on the finding of eburnation, or of pitting, osteophyte and change m the bony contour. 2 Based on standard radiological criteria.


(a) Rotator cuff enthesopathy in which new bone is found on the greater and lesser tuberosities of the humerus, on th anatomical neck of the humerus where the glenoid labium inserts, around the rim of the glenoid and on the coracoid process of the acromion. The insertion of the supraspinatus tendon is said to be most typically affected.

(b) Humero-acromial impingement following disruption of the rotator cuff and upward displacement of the head of the humerus. There is eburnation on the head and greater tuberosity of the humerus and the inferior surface of the acromion and generally new bone around the rotator cuff insertions. Rarely a subacromial spur may be seen arising from the insertion of the coraco-acromial ligaments. This arises in response to subacromial bursitis.

(c) Osteophytosis around the bicipital groove. The position of the new bone formation reflects different pathological events. Osteophytes on the medial wall of the groove indicate tension in the transverse humeral ligament; on the floor of the groove they are probably the result of chronic bicipital tendinitis. Along the length of the groove or on both sides, osteophytes represent ossification of the bicipital sleeve. If a tunnel of osteophyte is present over the groove, this reflects ossification in the transverse humeral ligament. Good bone preservation and careful examination are necessary to make these distinctions.

OA OF THE KNEE JOINT

As mentioned in Chapter 2, the knee joint is anatomically a compound joint with three compartments, the patellofemoral joint (see Figure 4.4), and the medial and lateral tibiofemoral joints (Figure 4.9). Recently, clinical research has drawn atten-tion to the fact that OA in the three compartments behaves differently, with distinct incidence and prevalence rates in th population and with distinct risk factors for each. In a recent study we have found a similar pattern in skeletal material with patellofemoral OA being three times as common a tibi f m ra I OA. Because of the clinical acceptanc that th diff r nt , n·. H

are likely to hav diff r n t aus s or rink f tonl, , n I diffn, •n l

Osteoarthritis 4

1 11urc 4.9 Archaeological specimen showing oste?arthritic change on. medial llil.11 joint surface. Roughening, pitting, osteophytos1~ and som_e chan~e 1n bony

contour are all evident. There was no eburnation on th1s spec1men

lll'<'valences in males and females, it is legitimate to record and 11 wlyse the compartments of the knee separately in skeletal l11dies.

PALAEOPATHOLOGICAL CLASSIFICATION

'l'h ' clinical diagnosis of OA depends upon the presence of pain 1n I certain clinical signs; the radiological diagnosis depen~s ltpon demonstrating joint space narrowing. None of t~ese IS lwlpful for a palaeopathological dia~osis. and. so different n it ria have to be adopted while bearmg m mmd fl_lat t~ey 1111tst correlate as closely to the clinical and rad1olog~cal dingnoses as possible; this is particularly important. in the c~se of r, di lo ical diagnosis since it is on this that our information un mod rn pr valence data derives.

'l 'lw P· 1. o . thologi AI diagn i of OA should be simple and t l1' 1lghlforw nrd; il dl' l ndH fin; t . nd for mo t on demon-ll' lling llw pn•1 t ' lll'l ' of 1•hurn !l ion (Plp urt•s 'I·. - 4.13). Whcr


Figure 4.10 Post-mortem specimen showing area with total loss of articular cartilage on the patellofemoral joint and subsequent eburnation

eburnation is absent, then we suggest that it should be diagnosed only when at least two of the following are present:

• marginal osteophyte and/ or new bone on the joint surface; • pitting on the joint surface; or • alteration in the bony contour of the joint.

In practice, little will be lost by restricting the diagnosis to include only those joints which show eburnation, although in some special circumstances, such as with a mushroom-shaped femoral head, the changes in joint contour and pitting on the joint surface are so obviously abnormal as to leave no doubt about the diagnosis.

OA must never be diagnosed if marginal osteophytosis is the only abnormality, and whatever criteria are used these should be clearly stated in a paper or bone report.

When calculating the prevalence of OA in sk letal opu lntionH, the precautions noted in hapt r 2 hould b borrw i11 •nind .

Osteoarthritis IJ !,

Figure 4.11 Osteoarthritis of the thumb base (first carpome~acarpal joint) •:bowing eburnation on the plantar aspect and hy~e~roph1c osteophyte formation. (Note archaeological numbering on. the JOint surface. Please

discourage wherever poss1ble)

haracteristics of osteoarthritis

• disease of articular cartilage • probably represents the end product of normal re-

modelling of a failed joint • prevalence increases with age • more common in females and males • eburnation is pathognomonic • marginal osteophyte is usual • may be n w bon or pitting on joint surface • joint r tour m, y b alt r d

A I i ·Id Guide to Joint Disease in Archaeology

Figure 4.12 Osteoarthritis of the odontoid peg with eburnation and p'tf the joint surface 1 mg on

Figure 4.13 Skeleton ~n .situ ~rior to lifting showing osteoarthritis of th JOint With marginal osteophytosis left hip

5 Diffuse Idiopathic Skeletal

Hyperostosis

rn 1950 Forestier and Rotes-Querol described a disease of the spine in old people with a form of fusion different from anky-losing spondylitis (AS) and which they called senile ankylosing hyperostosis of the spine. The disease was relatively painless and was thought to be a variant of OA, under which heading it is still sometimes included. The spines of affected individuals have typical and striking X-ray changes with fusion on the anterolateral aspect of adjacent thoracic vertebral bodies, almost invariably on the right-hand side. After the original description of the condition in the spine it came to be referred to ponymously as Forestier' s disease.

Resnick subsequently reported that many of those with Forestier's disease also had ossification of ligament insertions (or entheses) at peripheral sites in addition to the typical changes in the spine. Resnick referred to this set of signs as diffuse idiopathic skeletal hyperostosis (DISH) and considered that it was an enthesopathy in which there was ossification of the entheses and fusion of at least four adjacent thoracic vertebrae. Fusion was often present in more than four thoracic v rt brae and could also occur in the cervical and lumbar r ion , although in these regions it was not limited to the rip·ht-hnnd sid . The facet joints of the spine are not usually involv d . nd 1'11 dis s a s r maintained unl ome other pin tl di t>n t• iH ol. o 1 rl' l'lll..


Jn the 1970s Julkunnen carried out a survey of several thousand people in Finland and confirmed the prevalence of DISH to be between 6 and 12% as others had shown before him. He found that males were affected more often than females and that 85% of those with the condition were over 50 years of age. He also confirmed that symptoms were minimal and, where present, usually confined to some stiffness and aches and pains. In 25% of cases of DISH Julkunnen found an association with adult-onset diabetes and there was an association also with obesity.

In the palaeopathologicalliterature, especially before the 1950s when DISH was first described clinically, skeletons with the condition were frequently misclassified as having AS. This is especially the case in some of the earlier reports of Egyptian material. Re-reading some of the detailed descriptions of the distribution and form of the · spinal fusion, however, it is clear that the majority of these cases are actually DISH. DISH has been found in skeletal material from all archaeological periods from Neanderthal to the most recent.

The prevalence of DISH in most skeletal populations is, in general, similar to that in modem populations but there are some striking variations within burial grounds. At Wells Cathedral all the cases of DISH were found buried in side chapels with a prevalence of 20-30%, confirming a trend noted earlier at Merton Priory that there was a notably high preva-lence of DISH in monastic and often high status burial grounds, such as those where benefactors of ecclesiastical institutions might be buried. Although this is a trend which has been noted elsewhere in skeletal assemblages, care must be taken not to assign a particular status to an individual skeleton on the basis of the presence of DISH, nor inferences drawn about its association with other conditions such as diabetes or obesity; this can be attempted only at a population level.

PATHOLOGY

DISH is characterised by ossification of th ant ri or longi-tudinal spinal ligament and by o sifi < li n ir t·o l' I rn 1 in d

Diffuse Idiopathic Skeletal Hyperostosis 4

rigure 5.1 Spine showing typical ~hanges of diffuse id!opathic s~e l etal hyp rostosis with flowing candle-wax-lrke new bone on the nght-hand s1de of

the thoracic vertebrae

t>nth.eses. The development of new bone in the skeleton may n·n h prolific proportions and has been likened to candle w~x llowin down the spine and may reach up to 20 mm m thi kn (Figures 5.1 & 5.2). In the thoracic spine the restriction of ·h ng to the right side is said to be due to the presence of t I w pulH ting d s nding aorta on the left. There .have bee~ ,.,.1 orL· of I ft-Aid d 'fSH in pati nts whose descendmg aorta IS )

m1 tlw rl gh l Hid t• bul to our kr c wl dg th r hav b n no su h n•pmt ~ In n flkch•lon to d lit •.

',() A Field Guide to joint Disease in Archaeology

Figure 5.2 Radiograph of specimen shown in Figure 5.1 . Note the normal disc spaces and normal facet joints

Other spinal ligaments may also become ossified; it is common to find the ligamentum flavum, the supraspinous ligaments and the ligaments around the sacrum ossified. When the sacral ligaments are ossified they may bridge across the joint line, completely or not, bilaterally or unilaterally, and in this way fuse the joint (Figure 5.3). This type of fusion may be dis-tinguished from that which is found in the seronegative arthropathies (Chapters 7 and 8) since in the latter, the fusion is the result of intra-articular pathology.

Outside the spine, any enthesis may become ossified but the common sites are around the elbow, particularly the triceps insertion, the insertion of the quadriceps femoris into the patella, the insertion patellar ligament into the tibia and the insertion of the Achilles tendon into the calcaneum (Figure 5.4). It is important to remember, however, that entheses may become ossified for other reasons, including mechanical trauma, such as occurs in tennis elbow.

In patients with DISH there is often evid ne of al ifi lion into soft tissues including artil~g • and b l od Vl'RI·w l nnd in

Figure 5.3 Fusion of sacro-iliac joint by ossification of sacral ligaments in a case of DISH

keletons which have been well excavated with good bone recovery it is not uncommon to find ossified tracheal rings. ~nd laryngeal cartilages; the costal cartilages are. also often oss1fie~. These features are also found in skeletons w1thout DISH and m themselves are not diagnostic.

PALAEOPATHOLOGICAL DIAGNOSIS

DISH is one of the easiest conditions to diagnose in skeletal material. The fused block of thoracic vertebrae with exuberant new bone flowing down the right side of the vertebral bodies should be immediately obvious. To conform to the clinical de cription of DISH, at least four adjace~t vertebrae sho~d be fu ed, but it is not at all uncommon m skeletal matenal to find skeletons which obviously have DISH in which less than four are fused although the ossification of the anterior longi-tudinal Jigament involves many contiguous vertebrae. The pol-llC'rior v rt brc I joinlA . nd th disc spa~es are preserved 111d llw(• ft• tlll l'l 'l e H\ n•Hii l b onfumd on X-ray.


Figure 5.4 Enthesophytes on the patella and Achilles tendon insertion of the calcaneum characteristic of diffuse idiopathic skeletal hyperostosis or bone

forming

Enthesophytes will be apparent at extraspinal sites, some of which may be extremely florid. Fusion of the sacro-iliac joints at the ) anterosuperior margins is common but X-rays will demonstrate that the joint surfaces are normal and the joint space is preserved.

Where DISH is coexistent with OA the degree of osteophyt around the affected joints may be considerable (Figure 5.5) and we have seen a single case of DISH in which the detach d lamina of a lumbar vertebra with spondylolysis had b om reunited to the vertebra with new bon whi h h, d form I around the sit s of th (Ta tur .

Diffuse Idiopathic Skeletal Hyperostosis !d

Figure 5.5 Florid marginal osteophytosis in a case of diffuse idiop~thic skeletal hyperostosis without osteoarthritis. Also note enthesophytes on t1b1al tubercles

Bone formers

'fhere is a subset of the skeletal popul~~ion.~ which ?~sifi~ation of the entheses, fusion of the sacro-iliac JOmts, ossification of

< rtilage and large marginal osteophytes is eo~?~ and these w have termed bone formers. Some of these md1v1duals may go on to develop DISH, which in itself may be ~art of the 11p tt:um of bone forming (Figure 5.6). Hypertrophic OA ~~y t!Ho fit into this category. If bone formers develop another JOIDt

< 1 h-1 'nH u h ~ RA, its morphology may well be altered or 1110dlfil' I by tl ir bon formin t nd n y.


Figure 5.6 Excess bone formation after rib fracture in a case with diffuse idiopathic skeletal hyperostosis

Characteristics of DISH

• disease of ligaments and entheses • ossification of anterior longitudinal spinal ligament

produces candle wax appearance • spinal fusion with preservation of facet joints and disc

spaces • ossification of entheses at extraspinal sites • prevalence increases with age • more common in males than females • associated with diabetes and obesity

6 Rheumatoid Arthritis

RA is one of the diseases which is generally considered to be of recent origin. It was first described clinically in a thesis in L800 by Landre-Beauvais who believed that it was a variant of gout and referred to it as goutte asthaenique primitive: There have been very few cases recorded in the palaeopathological literature, although some are now beginning to come to light rmd we have described two recently. Claims such as those of Wood Jones that RA was the most common disease to afflict the skeletons which he examined from Nubia are explained by the fact that he was actually referring to what we now call OA, and not RA.

fn modem populations, RA is a common condition, affecting about 1% of the total population. Women are more likely to be affected than men in a ratio of about 3:1, and perhaps as many as 5% of the female population over the age of 65 has the disease. The disease is universal in occurrence, although some populations, such as those of black Africa are relatively spared. fn the countries of western Europe, the disease is declining in incidence but it is becoming more common in the developing ·ountries. In some developing countries, such as Pakistan and Malaysia, the expression of RA is different from that in the W st. For example, the feet are relatively spared compared with West rn ea es. It is quite likely the expression and distribution of RA in past population w r different from those in con-lt'nq Ol'fli'Y rorul. lion nd l'his is an important con ideration

1)(, A Fi Id Guide to joint Disease in Archaeology

for palaeopathologists. The same stricture almost certainly applies for other diseases also.

The disease has its onset most commonly in the fourth and fifth d ecades but no age-group seems to be exempt and classic adult-type disease may be found in children and it may also make its first appearance in the elderly. There is a tendency for the disease to run in families but this probably reflects a shared environment rather than hereditary factors.

r The cause of the disease is not known with any certainty although the modem tendency is to consider it to be multi-factorial in origin which is to say that any number of different possibilities have been considered. As with AS there is some evidence of a link between tissue antigens and a predisposition towards the disease. In the case of RA there is an association between the possession of some of the subtypes of the HLA-DR4 antigen and the occurrence of the disease.

PATHOLOGY

RA is a disease of the synovial membrane that becomes infiltrated with inflammatory cells, which cause it to become thickened and vascular. Continued inflammation produces a chronic state in which the diseased synovium is referred to as a pannus. This grows out from the joint margin to cover and then destroy the articular cartilage with the formation of erosions which are first seen at the margins of the joint. As the disease progresses, the joints become deformed and may dislocate; however, it is rare for joints other than the wrist or the tarsus to fuse in RA. Patients in the end stage of RA may be extremely disabled with crippling deformities of the hands and such individuals are still not uncommonly seen. It is hard to imagine that such extreme manifestations of the disease would have escaped the attention of writers or artists in the past had they been as common as they are now.

( The onset of RA characteristically involves the small joint of th hands and feet, especially the PIP, the m ta arpoph~ lang a t

1 an th m tatarsophalang al (MTP); th Tl jointA n• tnu h

Rheumatoid Arthritis 7

I ss frequently involved (Figures 6.1-6.3). Th~ distribution is 11 uall symmetrical and the sacro-iliac joint IS almost never nffect~ and when it is, the lesions ~re seldom severe. Other . oints become affected as the dise~se progresses, most I mmonly the wrist, knee, cervical spme, shoulder, subtalar joint, elbow and hip (Figures 6.4-6.6).

I t is usual for bones around an affected i?~t to b~co~~ ost o aenic and eburnation may supervene ~~thin an ~ ec e . . t ~ th wake of the destruction of the articular cartilage. 1otl'l · m

( 'I' . lly ut thr ·<.·- lh rt rs f pati nts with RA are found tnt , • 1 ) I ol ul s

to h wt• .ml ibodil• (tt l4 tt dl of tlw lgM a. 8 to g m .

I I

1\ I i •Id Guide to joint Disease in Archaeology

Figure 6.2 Carpals, one metacarpal and one proximal phalanx from the same case as shown in Figure 6.1 showing non-proliferative erosions

in their blood and these antibodies are referred to as rheumatoid factor (RF). It was the discovery that patients with what were thought to be atypical forms of RA did not have RF in their blood which gave rise to the concept of the sero-negative arthropathies. (The differences between RA and these disorders are discussed in Chapters 7 and 8.)


The diagnosis of RA in the skeleton depend upon finding t·h<· presence of ymm trica l, non-prolif re tivC' roslor H nffc•cling llw

Rheumatoid Arthritis

Figure 6.3 X-ray of Saxon skeleton with erosions at the metacarpophalangeal joint typical of rheumatoid arthritis

small joints of the hands and feet. One difficulty which is very likely to be encountered is that, since the bones in an affected ase will almost certainly be osteopaenic, there is a great risk of

them suffering post-mortem damage and important elements of the skeleton will be lost. We must emphasise that in our view it would be well nigh impossible to sustain a diagnosis of RA in a sk leton in which the hands and the feet were missing; the I iagnosis must never to be made on the basis of lesions which

n r found in a ingle, large joint, although this will un-doubt dly t net to unci<'r stimate its prevalence in the past. For ,, nm1 1<·, W<' h lV• ' t •'<'ll t•h mgi'A whi h look typi al of RA in


Figure 6.4 Elbow joint from the case shown in Figure 6.1 with non-proliferative erosions

Figure 6.5 Radiograph of the prox imal ulna shown in Fi rur 6.4. N 1 . sclerotic margin of eros ions indi ting r m d lling

Rheumatoid Arthrit'is (, 1

Figure 6.6 Erosions on the facet joints of a thoracic vertebra from the case shown in Figure 6.1

isolated large joints but in the absence of the hands and feet we have been reluctant to make a definite classification.

The lesions must be true erosions. There are many occasions on which skeletons are found with what might be called 'pseudo~ •rosions'; these are particularly common in the wrist, ankle and around the shoulder and these must not be confused with the lrue erosions found in RA although we believe that this is sometimes done (Figures 6.7 & 6.8). Radiology is helpful in

istinguishing true erosions from pseudo-erosions and good films will show the loss of cortex and the trabeculae ending in mid-air. The advice of an experienced skeletal radiologist may prove invaluable where there is any doubt as to the nature of I ions around a joint.

'l'h rosions in RA begin at the joint margins and encroach furth r ov r th joint urface as the disease progresses. If there nr(' 11 0 I . ions on th joint margins, you should think of some c 111. (' for tlwm c I her lh 111 RA .

A h Id Guide to joint Disease in Archaeology

Figure 6.7 Head of humerus with remodelled erosion at the joint margin. There are numerous 'pseudo-erosions' in the floor of this lesion

Many of the large joints can be symmetrically affected as we have mentioned above, but the sacro-iliac joint is usually spared and the cause of erosive lesions in a skeleton with disease of the sacro-iliac joints is not likely to be RA

There are no signs in the skeleton which are pathognomonic of RA, but it is possible that RF survives in the bone as many other bone proteins are now known to do. If this were to be the case-and this possibility is presently being investigat d- then finding RF in a skeleton which was thought to hav · RA would be strong supporting evidence; the abs n of RP, I .ow v r, could not b tak n to prov tht~t th diH a. c wnH 110/ RI\ .

Rheumatoid Arthritis

Figure 6.8 Scaphoid showing presence of a large marginal 'ps~ud<_>-erosion' and several smaller ones. In neither this case, nor the one shown m figure 6.7, were there any X-ray changes or any othe.r skele~~l changes to support a

diagnosis of rheumatoid arthntis

Characterisitics of rheumatoid arthritis

• disease of the synovium ( • non-proliferative symmetrical erosions beginning at the \ margins of the joint

• proximal interphalangeal, metacalf'~phalangeal and metatarsophalangeal joints charactenstically affecte~.

• may also affect wrist, knee, shoulder, subtalar JOmt, cervical spine, elbow and hip

• sacro-iliac joints not usually affected • bony ankylosis not common except occasionally at

carpus • osteopaenia common • may be eburnation on affected joints • annat be diagnosed confidently if hands and feet are

miRAing

7 Ankylosing Spondylitis

AS is a disease which appears to be of considerable antiquity 0\ and it is probably the most likely of the seronegstixe arthro-

pathies to be reported in the palaeopathological literature. While some of these are undoubtedly genuine cases, many more are probably misdiagnoses and the nature of these is presently under review. In the older medical literature, and occasionally elsewhere, it may be referred to as Marie-Striimpell, or von Bechterew's disease; however, there is nothing to commend the continuation of such usage.

AS is a disease characterised in the living by an inflammat cy Cl'---~ and by involvement of the entheses. In modem

populations it is more common, and more severe, in males than in females; the disease declares itself with significant symptoms in approximately 0.5% of men and 0.05% of women and the peak onset is in the late teens or early 20s. Milder forms of the disease with radiological evidence of sacro-iliitis may be seen in up to 3% of males and 2% of females. There seems to be an important genetic component in the aetiology of this condition and there is a strong association between the occurrence of th disease and a tissue antigen referred to as HLA-B27. Approxi-mately 95% of patients with AS have this antig n compar d with less than 10% of the general population. It is id to o ur in some animals, including do , a ttl and pi gH.

ILIOLUMBAR LIGAM ENT

l.UMBOSACRAL LIGAMENT

VENTRAL !l ACRO - ILIAC l iGAM ENT

Ankylosing Spondylitis

THE SACRO-ILIAC JOINT

Figure 7.1 Diagram of the sacro-iliac joints

PATHOLOGY

INTEROSSEOUS SACRO - ILIAC LIGAMENT

SYNOVIAL SACRO-ILIAC JOINT

The disease usually begins in the sacro-iliac jo~ts. ~nd the lumbar spine. The sacro-iliac joint is a com~os1tE~ JOmt; the lower two-thirds is synovial and the upper third ligamentous but both compartments are affected in AS (Fi~e 7.1). Both sacro-iliac joints are invariably affected and er?swns . m~y be

t The Patholooical changes are symmetncal within the presen . o- . . . f th · · t joints but are more obvious on . the I~ac . side o e ~~m , perhaps because the articular cartilage IS thinner ?I_l the iliu~ than on the sacrum. As the disease progresses the JOIDt space IS narrowed and fusion occurs across it.

In the spine the disease begins as an enthe~opathY_ at the · t . of the outer fibres of the annulus fibrosa mto the mser 1on . his · · Th vertebral body and erosions may be seen m t positw.n. e I. ts then become ossified and the vertebral bodies are 1 amen · · t th

Haid to become 'squared' (Figure 7.2). Inflammation m o . . e nth r spinal ligaments follow s an~ ~ey ~ay all.become ossified 1 'c ding to a completely ossified, n g1d spme which may. then. be r .f 'rr d to as a 'bamboo spine' because of the r~d~ological

, . Th li am nt around th costovertebral JOmts may l m an . f d t tl 11 .0 be omc i1 v lv d s tl nt thr ribs b om IX on o 1

pirw.


Figure 7.2 Radiograph of mo~ern patient with ankylosing spondylitis to show typ1cal bamboo spine'

One of_ the im.J?ortant features of the spinal pathology in AS is that spmal fuswn begins in the lower lumbar region and as it proceed~ up';ard~, none of the vertebra is spared so that there are ~o. skip leswns as there may be in Reiter's disease or psonabc arthropathy (P A), for example (see Chapter 8).


The ~~st _o~wious feature in a sk 1 ton with A is tl n t tlw sacro-Iliac JOmt w j]l b fl.1 , d and the t th r · wi ll b(• 1 vnl'l lh lt•

Ankylosing Spondylil'i ·

Figure 7.3 Fused spine from an archaeological case of ankylosing spondyl itis. Note complete fusion of vertebrae with no skip lesions . Several ribs have been fused to the vertebrae, although subsequently damaged; the sacro-i liac joints

are fused

degree of fusion throughout the spine (Figure 7.3). The fusion will always affect the lowest parts of the vertebral column and if it advances upwards it will usually do so without missing out any elements. As the fusion increases upwards there is often a degree of kyphosis. In advanced cases the ribs may be f us d to the vertebra and the entire vertebral column and thora ic cage may be lifted up as a single entity.

'J'Iw , . ro-i l i. j ints may fus in DISH and the ribs may also on 1 ion 11ly lw fu .-t•d to tl t' v(•rt('brr , but spinal fu ion du to

1111 A I idd Guide to joint Disease in Archaeology

I I ' 11 is generally easily distinguished from AS because in DISH the osteophytes are much more massive and irregular, and in the thoracic spine at least are almost entirely confined to the right-hand side.

In the cases which we have observed there may be very little change outside the spinal column, although conversely there may be prominent entheses at almost any muscle insertion; it is unusual to find other joints affected but, of course this cannot be ruled out.

Radiography may be helpful in demonstrating the typical bamboo spine (Figure 7.2) and there may be some virtue in trying to obtain radiographs of the sacro-iliac joints to demon-strate the presence of erosions, although those inexperienced at X-raying dry bones may find some difficulty in lining the joints up in the correct position.

It is possible that in the future HLA antigens may be extractable from bone and the presence of HLA-B27 would be confirmatory evidence of AS but its absence could not preclude the diagnosis. We are some way off being able to do this, however, and even if the technique becomes available, it would probably not be widely available. The extension of palaeo-immunology to the study of the rheumatic diseases in antiquity, however, is something which should be welcomed and may provide useful information in the future.

Characteristics of ankylosing spondylitis

• disease of synovium and entheses • sacro-iliac joints affected symmetrically • sacro-iliac joints often fused in the skeleton • X-ray of sacro-iliac joints may show erosions • erosions may occur in large joints • spinal fusion begins in lower lumbar region and pro-

gresses steadily upwards • no 'skip' lesions • kyphosis is often a feature • ribs may be fused to vertebrae

8 Other Seronegative

Spondlyoarthropathies

The seronegative spondyloarthropathies are a group of erosive, inflammatory polyarthropathies, which also affec: entheses. Thus the inflammatory process involves the ligamentous insertions (the entheses) as well as the internal s~ctures of the joints. They were originally consider~d to b~ vanants of ~.but it was when it was found that patients with these condit~ons did not have RF in their blood they were categonsed eparately. They all have overlapping clinical features . . ~~d

which, so far as the skeleton is concerned, include sacro-iln~IS, pondylitis and peripheral arthritis. There . are ~ee maJOr

seronegative spondyloarthropathies: AS (considered m Chapter 7), PA and Reiter's disease.

Pathologically and radiologically, PA and Reiter's disease sh~re everal features in common although they can be readily

distinguished clinically. In the absence of clinical informa.tion It may be difficult to differentiate one from ~e other ~ the sk 1 ton, although in typical cases there are differences ~ t~e morph logy of the lesions and in their distribution, both within th, fl in an riph rally, which may enable a palaeo-pathologi . I linpno i to b mn


PATHOLOGY

As in RA, the target area for pathological change is the synovial membrane and the same series of inflammatory changes as is observed in RA occurs in the seronegative arthropathies also. The synovium becomes infiltrated with inflammatory cells, proliferates and becomes thickened. As the disease process progresses the articular cartilage is destroyed and there is a much greater tendency for the joints to fuse; this is particularly the case with P A and AS. Marginal and central erosions may be observed and there is a good deal of new bone formation, unlike the situation in RA. There may be joint destruction, especially in P A when changes reminiscent of those seen in RA may be found.

The other major characteristic of the seronegative arthropathies is the involvement of tendons and ligaments which may be ossified and may also be the site of proliferative erosive lesions (Figure 8.1). The ossification of the spinal ligaments accounts for the spinal fusion which is almost always seen. Periosteal new bone may also develop, particularly in Reiter's disease, and may gives rise to 'whiskering' on X-ray.

X-rays of affected skeletons may show the presence of erosions, proliferation and ankylosis, and in addition there may be evidence of resorption of the tufts of the distal phalanges in P A. Osteoporosis is much less common than in RA. The changes in the sacro-iliac joints are asymmetrical and may be unilateral.

PSORIATIC ARTHROPATHY

The first association between the skin disease psoriasis and arthritis was made by Alibert in the 1850s. The condition was first thought to be part of the spectrum of RA or a variant of it, and w as only separated from it in 1964. Psoriasis affects about 1% of the population but only about 5-8% of patients with th condition go on to develop the arthropathy; mal and f mal s ar aff cted qually.

Figure 8.1

Other Seronegative Spondlyoarthropathi s 7 1

Erosive lesion on the olecranon process in a case of psoriatic arthropathy

The arthropathy is usually asymmetrically distributed with a preferential involvement of the DIP, PIP and MTP joints. The changes in P A are often not very marked but there is a severe, mutilating form in which the interphalangeal joints are destroyed leading to bony ·ankylosis and telescoping of the digits (Figure 8.2). The proximal end of the distal phalanx is often widened while the distal end of the middle phalanx undergoes osteolysis and becomes pointed to produce what is known radiologically as a 'cup and pencil' deformity. This condition is often referred to as arthritis mutilans. The appear-ance of this form of P A can mimic the deformities found in j pro y and many cases of leprosy described in the past may , tually hav b n PA, especially considering the skin changes.

'onv •rs0ly, som s of pala opatholo ical cases of PA may H' lllnll lw lt•pro .

I

I I

I


\ _

Figure 8.2 Psoriatic arthropathy showing fusion and shortening of the proximal and middle phalanges. Note also the erosion at the proximal end of the

proximal phalanx

In the sacro-iliac joints the changes are similar to those seen in AS but they are usually unilateral or asymmetrical in distribution (see Table 8.1). In the spine there may be some fusion of adjacent vertebrae with the cervical spine being affected more frequently than the thoracic or lumbar. The ankylosis in the spine often takes the form of paravertebral ossification, that is, large chunky outgrowths of bone situated unilaterally. In the cervical spine the facet joints may also be involved and there may be marked bone excrescences alon th margins of the vertebral bodies.

Other Seronegative Spondlyoarthropathi s 7J

Figure 8.3 X-ray of the foot from case as 8.2 showing fusion of the tarsus and the tarsometatarsal joints. There are erosions at the first distal interphalangeal

joint with expansion of the proximal end of the first distal phalanx

Radiographs will confirm the presence of marginal and central erosions, of bony ankylosis and proliferation of new bone (Figure 8.3).

REITER'S DISEASE, OR REACTIVE ARTHRITIS

Tn 1916, Hans Reiter first described the association of signs and . ymptoms whi h has ub qu ntly taken his name. In addition t) nn a rthriti., o t·h r P< ti ntR had onjun tiviti and urethritis md l'lw !' nfl1•n OC<' tlrr'!'d 1flcr n dinrrho nl illn BR, Btl h RA

A held Guide to joint Disease in Archaeology

dy ntery. The possibility that arthritis might be a complication of urethritis or might follow a gut infection, however, had been noted much earlier, in the sixteenth and seventeenth centuries.

This type of arthritis, which occurs after some triggering infection usually affecting the gyt or acquired during sexual intercourse, is a reaction to the infectious organism and differs from septic arthritis in which there is a direct and immediate infection of the joint tissues.

Reiter's original case was a male and it is still the case that males are more commonly affected than females; the prime age of onset is between 15 and 35 years.

The pathological lesions on the bone look very similar to those of P A, as do the radiological changes, but their distribution may be different. The erosions in Reiter's disease are marginal as in P A and there is adjacent proliferation of new bone; they are also asymmetrical but they tend primarily to affect the lower extremity. The preferred sites are the small joints of the foot, the calcaneum, the ankle and the knee (Figure 8.4). The sacro-iliac joint is affected and there may be paravertebral ossification. The cervical vertebrae are affected less often than in PA, and throughout the spine there may be so-called 'skip' areas where normal vertebrae are found interspersed between the affected ones.

In addition to new bone around the erosions, there may be proliferation of the entheses on the plantar surface of the calcaneum, on the ischial tuberosities, the femoral trochanters and the sacro-iliac joints. Periosteal new bone may also be seen in some cases along the shafts of the metacarpals, metatarsals, phalanges and on the tibiae (Figure 8.5).


In practice it is very difficult to differentiate P A from R iter' disease and this may also be the case clinically, but th r ar some pointers which will h lp in thi task ( T. t If' 8.1 ).

Other Seronegative Spondlyoarthropathies

Figure 8.4 Metatarsals from a case of seronegative spondyloarthropathy with proliferative erosions on the head of the first metatarsal and fusion of the tarsometatarsal joint with some hypervascularity; probable case of Reiter's

syndrome

The first stage in palaeopathological classification depends upon finding the presence of an asymmetrical erosive arthro-pathy with proliferation of new bone around the margins. The distribution of the lesions will be a guide towards the classification; in P A the small joints of both the hands and the feet are affected, whereas in Reiter's disease, the feet are much more often the preferred site. In both conditions bony ankylosis may occur but it is more common in P A; arthritis mutilans does not occur in Reiter's syndrome.

In both conditions there may be sacro-iliitis with fusion of the acro-Hiac joints, and there may be paravertebral ossification. In

PI\ th c rvical pine is more commonly affected than the other rc•g ionH, ~ nd in R it r's dis AS th r may be skip lesions. In R<' iiN'Ii di N l ' t' llw t•nllw t'. on J·h plan tar surfa of th


Figure 8.5 Radiograph from a modern case of Reiter's syndrome showing periostitis on the shaft of the fourth metatarsal with thickening of the distal part

of the shaft

calcaneum may be involved and there may be periostitis on the shafts of the long bones of the hands and the feet and on the tibiae.

Where a definite classification cannot be achieved, and this may well be the case with damaged or incomplete skeletons, it i best merely to classify the changes as those of an rosive arthropathy of the seronegative or r activ typ an not attempt any furth · r di tinction.

Other Seronegative Spondlyoarthropathi s

Table 8.1 Some features of psoriatic arthropathy and Reiter's di sease

77

Psoriatic arthropathy

Lesions peripheral and axial Generally asymmetrical Upper extremity affected more often than lower Marginal and central erosions with proliferation of new bone Tuftal resorption Arthritis mutilans with pencil and cup lesions Sacro-iliac joint involved Changes may affect entire spine, especially cervical

Reiter's disease

Lesions peripheral and axial Generally asymmetrical Lower extremity affected more often than upper Marginal and central erosions with proliferation of new bone

Sacro-iliac joint involved Lower spine tends to be affected, skip lesions present Enthesopathy around calcaneum Periosteal new bone on shafts of long bones of hands and feet and on tibiae

Characteristics of seronegative arthropathies other than anky-losing spondylitis

• lesions asymmetrically distributed • erosions marginal and central with proliferation of new

bone • sacro-iliac joint involved • paravertebral ossification with spinal fusion • may be skip lesions in spine • ossification of entheses • periosteal new bone on shafts of long bones of hands

and feet 11

9 Gout

Gout can be recognised from descriptions written by early clinicians, including the authors of the Hippocratic corpus, although the term gout, from the Latin gutta, meaning a drop, was applied indiscriminately to many joint afflictions.

Gout is caused by an inflammatory response to the deposit of crystals of uric acid with the joint tissues. The deposition of crystals is secondary to high uric acid levels in the blood (hyperuricaemia) which may be due to genetic or environ-mental factors. Hyperuricaemia may be present in a patient for many years before an attack of gout occurs and indeed, in some of these people, gout never manifests itself. The classic site for the disease is the first MTP joint but other sites may also be affected, those most commonly involved being the hand, wrist, elbow, knee and ankle. In the clinical literature it is said that the shoulder, sternoclavicular joint and sacro-iliac joint are less commonly affected and the hip and spine rarely, but this may not be the case in palaeopathology. In between 75 and 90% of all patients with gout the MTP will eventually be affected.

Attacks of gouty arthritis can occur in two forms, acute or chronic. The first attack of acute gout usually occurs in middle-aged men or post-menopausal women. Urate crystal ar deposited in the tissues causing exquisite pain, w lling and r dn s and th on t roay b v ry Au d n; th dis<· H<' m. y

Gout 7<)

attack a single joint or more than one. The attacks are If-limiting but nowadays are treated to speed recovery. Betw en attacks the patient is unaffected, but as time passes attacks may occur more frequently and each can last longer and affect more joints.

In about 50% of cases chronic gout eventually supervenes. It is characterised by the formation of tophi; these are firm, nodular swellings which may be yellowish in colour or exude white chalky material. The tophi are deposits of urate crystals which can be found in articular cartilage, subchondral bone, the synovial membrane, joint capsule and tendons, ligaments and bursae. Thus all the structures within and around the joint may be affected.

Until a few years ago very few cases of gout had been reported in the palaeopathological literature despite the undoubted reports of its occurrence in the early medical literature. One case was reported in an Egyptian mummy in which urate crystals were identified in a tophus and Calvin Wells reported a case in a male skeleton excavated from the Romano-British cemetery at Cirencester. This skeleton showed the typical X-ray changes and juxta-articular, punched-out erosions with under-cut edges around the feet (Figures 9.1 & 9.2). Since then many further examples have been recognised.

PATHOLOGY

It is the presence of tophi which cause the typical bony changes from which gout can be recognised in skeletal material. The bony erosions which give rise to the typical appearance can be situated in three locations around a joint. They can be marginal, sometimes extending towards the centre of the joint, they can be away from the margins or para-articular and eccentrically placed, or they can be somewhat remote from the joint, or juxta-articular when they are also typically eccentric in location.

.ouly ro ions are generally round or oval in shape and are ofl<'l'l in l·h long axis of th bon . They appear punched out

HO A Field Guide to joint Disease in Archaeology

Figure 9.1 Romano-British skeleton from Cirencester with extensive erosive lesions of both ankle joints

with overhanging edges (Figures 9.1-9.3). The distribution of the lesions is asymmetrical and on X-ray the margins frequently have a sclerotic margin and the overhanginge edges are sometimes referred to as Martell hooks; this latter appearance is typical of gout. Occasionally there is proliferation of new bone around the margins of an erosion and rarely bony fusion occurs. Osteoarthritic changes are also noted frequently both on X-ray and in -the skeleton.


Gout should be suspected on finding asymmetric, punch d-out lesions around or within a joint. The fe t ar m r fr u ntly aff t d than th r part of th k l ton, but gout rY~r nL o t ·

G ul' Ill

Figure 9.2 X-ray of one of the ankle joints shown in Figure 9.1 with undercut and sclerotic margins typical of gout

found in the hands, wrists, elbows and knees. This is a condition in which radiography is particularly helpful in making a diagnosis. The X-ray will usually show that the lesions have sclerotic, overhanging margins and that there is no significant osteoporosis associated with them. In some rare a es there may still be deposits of uric acid within the lesion

an if th. ir presence can be confirmed, this will leave the dingr o iA in n doubt (Figur 9.4).

H2 A Field Guide to joint Disease in Archaeology

Figure 9.3 Phalanges, metatarsals and navicular from a skeleton from Barton on Humber with extensive marginal erosions. Note Martell hook on the left-

hand side of the proximal joint surface of the first metatarsal

OTHER EROSIVE CONDITIONS

A small number of other joint diseases may also include erosions among their pathological changes. 1bree will be mentioned here.

The commonest of these conditions is hallux valgus of the first MTP joint (Figure 9.5). The erosions may be single or multiple and usually have smooth margins and are morphologically difficult to tell apart from the erosions due to gout or the seronegative spondylarthropathies. However, an X-ray read by an experienced skeletal radiologist should usually be able to distinguish between these various conditions.

Other erosions encountered in the hands, feet or-occasionally-in the knee, may be caused by synovial mass lesions (Figures 9.6 & 9.7). Synovial chondromatosis or pig-mented villonodular synovitis may produce thickened nodularities in the synovium which in turn may cause juxta-articular single or multiple erosions. There may b som difficulty in differ ntiating th ro ion from oth rs and X-r< ys will b rcquir to h lp I. rify 1'1 • dingn08iH.

Gout

Figure 9.4 Urate crystals from a modern case of gout

Characteristics of gout

• lesions caused by deposits of uric acid (tophi) • lesions may involve all the structures within and around

the joint • first metatarsophalangeal joint involved in about 75% of

cases • common sites include feet, ankle, hands, wrist and knee • lesions distributed asymmetrically and have punched-

out app arance with overhanging edges

continued overleaf


Figure 9.5 Erosions on head of first metatarsal in a case of hallux valgus

continued ------------------------, • may be proliferation of new bone around margins of

lesion • X-ray usually shows sclerotic margin around lesions and

confirms overhanging edges-Martell hook • osteoporosis uncommon

Gout 8

Figure 9.6 Knee joint with large juxta-articular erosions. There were no erosions elsewhere in the skeleton. This is a possible case of synovial

chondromatosis or pigmented villonodular syndrome


Figure 9.7 Single large erosion on the posterior surface of the distal femur. The rest of the skeleton showed changes characteristic of treponema! disease and

this lesion is likely to have been the result of a gumma

10 Infections Causing Joint

Disease

Many infectious organisms, bacterial, viral and fungal, may involve the joints but the most common, and those which we need to consider in detail here, are the organisms that cause osteomyelitis and tuberculosis.

OSTEOMYELITIS

Osteomyelitis is an infection of the bone and bone marrow most usually with bacteria and the most common infectious organism is Staphylococcus aureus, a bacterium most frequently encountered when it causes boils. The organism may gain entry to the bone by one of three routes:

(1) haematogenous spread (through the blood stream), the organism having got into the blood from a septic focus somewhere in the body;

(2) direct spread from infected soft tissues; and (3) by the direct implantation of an infected object such as

might occur with a penetrating wound.

T la mntog nous F!pr od is th mo t usual m an by which oAtc·om <·liliH i (' t 1hliHiwd in • bon -. st -omy llti ~:~ i,· mor

IlB A Field Guide to joint Disease in Archaeology

ommon in children than in adults and the preferred site of jnfection is at the growing end of long bones where the blood supply is richest. The organisms multiply in the bone marrow, which is an excellent culture medium, and an intense inflammatory reaction sets in with the formation of pus; regarding this, the infection is often referred to as pyogenic. The pus drains from the bone through channels which are called cloacae and during the course of the infection, portions of bone may become cut off from their blood supply and die, forming sequestra, which may only be visible on X-ray. The infection provokes the formation of a great deal of periosteal new bone formation and a collar of new bone may be formed around the shaft of the bone, when it is known as an involucrum. In long-standing infections the shaft of the bone may appear ~n; in some cases the infected bone may become weak and fracture. The combination of cloacae, sequestra and periosteal new bone is very characteristic of pyogenic osteomyelitis (Figure 10.1).

The age of onset of the infection may to some extent determine the appearance of the changes seen in osteomyelitis (see Table 10.1). Thus with an adult onset, the presence of sequestra and an involucrum are uncommon but pathological fractures are common; this is the converse of what is generally the norm in childhood cases. Joint involvement, by contrast, is common in adult-onset cases (and in infancy) but less common in childhood cases.

PYOGENIC ARTHRITIS

A pyogenic organism can spread to a joint through any of the three routes described above, but in general only a single joint is affected. The process is highly destructive; the erosive lesions tend to appear first at the margins of the joint but eventually virtually all the joint surface may be destroyed. The disease stimulates the production of much new bone and the end stage of the disease is usually bony ankylosis of the joint (Figur 10.2).

Infections Causing joint Disease 89

Figure 10.1 Tibiae in .a case of osteomyelitis. Both bones are swollen in their distal ends and, in addition, there is a cloaca on the right tibia, on the medial surface at the junction of the lower third and upper two-thirds of the bone. Scale

in cm

TUBERCULOSIS

Tuberculosis is caused by a mycobacterium and there are two principal species which affect humans, Mycobacterium bovis and M. humanis. The first organism is contracted from cattle by the ingestion of contaminated milk or dairy products. It spreads from the gut to the lymph nodes throughout the body and may come to be lodged in other tissues, including bone. The human organism probably evolved from the bovine type and it is pr ad through the air and so the site of entry is the lungs.

Wh n inhnl d, fh organism provok s what is known a a prirnnr n•HponHt', which 11 unll rc•su ltR inn AmL 111 Rion in th

110 A I i •Id Guide to joint Disease in Archaeology

L1hll• I 0.1 Features of osteomyelitis at different ages

loacae Sequestra Involucrum Joint involvement Pathological fractures

Infant Child (<1 year) (1-16 years)

Uncommon Common Common Common

Uncommon

Variable Common Common

Uncommon Uncommon

Adult (>16 years)

Common Uncommon Uncommon

Common Common

Figure 10.2 Proximal tibia showing destruction of joint surface with proliferation of new bone typical of pyogenic arthropathy

apex of the lung and swelling of lymph nodes within the chest. In many of those exposed the disease spreads no further but in some, after a variable time, the disease flares up and spreads through the lung and to distant parts of the body.

Both organisms can affect bone and the idea which is still current that skeletal infection is more common in the bovine than the human type is not true. The preferred site for infection is the spine, and usually the lower thoracic or lumbar region. The anterior parts of the vertebrae are affected in pr f r n t the posterior and th r ult is an r iv 1 sion whi h provoke,


Figure 10.3 Spine showing destruction of bodies of some thoracic vertebrae with collapse and resultant kyphosis. These are the typical appearances in Pott's

disease of the spine

little, if any, proliferation of new bone. In time the vertebrae become substantially weakened as they are destroyed and they may collapse resulting in an angular kyphosis, which may be seen referred to as Pott's disease of the spine (Figure 10.3).

Virtually any other bone may be affected by tuberculosis, but they will all show the characteristic erosions without proliferation. In children the metacarpals and phalanges are often affected, the condition being referred to then as tuber-u1ou dactyliti . In addition to swelling of the bones and lytic

1 ' AionA (Pigur 1 0.4), th r' mny b som p ri titi on th hnft H, tnd thh 1111 11 li11w,· lw quil l' (' ul ('l' nt.

\ I


Figure 10.4 Radiograph from a modern child with tuberculosis affecting the shoulder joint. A large erosive lesion on the lateral aspect of the humeral head is

·easily seen

Tuberculous arthritis

Tuberculosis tends to affect the large joints such as the hip and knee, but others may also be involved, including the elbow, wrist, sacro-iliac joints and the glenohumeral joint; it is rare for more than one joint to be involved in the process. The erosions in the joint tend to start at the margin, particularly in weight-bearing joints such as the knee, hip and ankle. There is little proliferation of new bone but the bones around the infected joint become porotic early in the disease. The end stage of a tuberculosis joint is usually fibrous ankylosis; bony ankylosis is unusual, which is in contrast with pyogenic arthritis where bony ankylosis is the norm. (Some of the features of tuber-culous and pyogenic arthritis are shown in Table 10.2.)

Tuberculous discitis

Radiologically, early lesions may be e n in th ant dor sub-chondral portion of a v rt ra just b n ath tl · int rvc rt 'I rnl

Infections Causing joint Disease 93 Table 10.2 Comparis9n of some features of tuberculous and pyogenic arthriti s

Erosions Proliferative new bone

Bony ankylosis Osteoporosis

Tuberculous arthritis Pyogenic arthritis

Yes Little if any except in tuberculous dactylitis Rare Common

Yes Much

Common Rare

disc. Extension of this lesion may cause it to perforate through the end plate and infect the disc and subsequently spread into the adjacent vertebra. This process cannot be observed directly in the skeleton but radiography of the vertebra may sometimes reveal a lytic lesion in the body, which may correspond to this early lesion . It may also be possible to observe defects in the end plate where such a lesion has erupted through (Figure 10.5). These are not to be confused with Schmorl's nodes, which are distinctive and will not be associated with any lytic lesions in the vertebral body.

Spread from this type of lesion may result in infection spreading to the anterior longitudinal ligament with erosions of the anterior face of the vertebral body and lesions of this type are sometimes seen in the skeleton.

BRUCELLOSIS

Brucellosis is an infection caused by one of the species of Brucella, which are transmitted from animals including the cow (B. abortis), the goat (B. mellitensis) or the pig (B. suis). It is transmitted through contaminated milk or dairy products or from direct contact with infected secretions and it is likely to have been common during periods when societies were living in close contact with their animals. It produces a monoarticular arthritis affecting the hip, knee and sacro-iliac joint most often, and it also affects the lumbar spine (Figure 10.5). The lesions may b difficult to diff r ntiate from tuberculosis, although t·h r t nd. to b · mor n w bon formation in bruc llo i than h tulwrc111o i 111d or-~ l.t •ot or·ot·liH i I<'RR ommon th, n in


Figure 10.5 Lumbar vertebrae showing erosive lesions on the end plate_s ~~th considerable proliferation of new bone. Probable case of tuberculous d1sc1tls

tuberculosis. There are no pathognomonic signs, however, and it is possible that some cases of vertebral lesions may, in the past, have been wrongly diagnosed as tuberculosis. With advances in the technique of polymerase chain reaction applied to bacterial DNA, it may be possible to differentiate the two diseases in the skeleton.

LEPROSY

Arthritic lesions due to the causative organism of leprosy (M. leprosa) are rare, but it is common for secondary infection to occur in patients with leprosy due to the loss of sensation, which results from the lesions in the nerves. In the foot this may lead to secondary osteomyelitis with involvement of any of the joints of the foot. The loss of sensation may also lead to recurrent trauma to the joints of the lower limb with subsequent malalignment and destruction; these are the so-called Charcot joints and they may occur also in syphilis wh n in the tertiary stage of the disea e th n rvous syst m is involv d .


FUNGAL DISEASES

Fungal diseases affecting bone and joints are rare in Europe but they are much more common in North and South America, and those who examine skeletons from sites in those countries should be aware of them. The two fungi which account for most skeletal disease are Blastomyces dermatitidis and Coccidioides immitis causing blastomycosis and coccidioidomycosis, respectively. In blastomycosis the vertebrae, ribs, tibia, tarsus and carpus may be involved with areas of moth-eaten bony destruction. Vertebral collapse may be seen which may be difficult to distinguish from tuberculosis. The joints are usually affected by the spread of the disease from adjacent sites but occasionally a monoarthritis is observed most frequently involving the knee or ankle joints. In coccidioidomycosis multiple symmetrical lesions are found in the spine, ribs and pelvis and sometimes in other bones; spinal collapse is uncommon. As with blastomycosis, joint involvement usually results from direct spread but a monoarthritis may also be found, and again the ankle and knee are the commonest sites.

There may be great difficulty in distinguishing fungal diseases from other infectious diseases, and in the case of coccidioido-mycosis sclerotic changes in the vertebral bodies may simulate prostatic carcinoma. In the future, fungal DNA studies may help in the diagnosis of these conditions.


Both osteomyelitis and tuberculosis are ancient diseases and there are examples from virtually all archaeological periods. In pyogenic arthritis there may well be signs of osteomyelitis in the long bones or there may be evidence of trauma around the joint. Where there is not, then the diagnosis depends upon the presence of proliferative new bone on the surface of the joint and, in some cases, ankylosis. There may be cloacae through whi h th pu drained from the joint during life. Radiography w i 11 show slru ti n and di or anisation of the joint.

Tlw di. •r.n(H it o lttlu•n•ulo i i rc·l. liv<' ly (',, y in the f11ll bl wn


spinal case with erosion of the vertebral bodies (massive in some cases) and little or no proliferation of new bone. Pott's spines are extremely characteristic and cannot easily be mistaken. The more difficult case is where joints outside the spine are involved. Here again, however, the combination of erosion without proliferation, and joint fusion are good indicators of the likely diagnosis. Recently, it has become possible to demonstrate the presence of bacterial DNA in bones from cases of putative tuberculosis. A positive result in such a test is confirmatory evidence for the diagnosis, assuming that the possibility of contamination can be ruled out. On the other hand, a negative result does not rule out the diagnosis since the DNA that might have been present in life could have been lost by any of the processes which disrupt the body and its component parts after death.

Characteristics of pyogenic and tuberculous arthritis

Pyogenic arthritis

• usually monoarticular • erosive lesions • much proliferation of new bone • bony ankylosis • may be the sequel to injury

Tuberculous arthritis

• lower thoracic and lumbar spine most commonly affected

• fingers affected in children • erosive lesions • little proliferation of new bone • spinal collapse with Pott's disease • fibrous ankylosis

11 Implications for Archaeologists

Skeletal studies, including palaeopathology, are generally undertaken with the main aim of informing the archaeologist about the physical attributes of the population being examined. Palaeopathological studies have, over the years, provided much information about some of the diseases and abnormalities which were experienced by early populations. Much infor-mation has been gained about the natural history and evolution of disease which is of interest to both biologists and clinicians. Skeletal assemblages can serve as a unique resource for some aspects of medical research, which may also be of great value to palaeopathologists and thus to archaeologists.

Recently, there has been a move towards expanding skeletal studies into a more biocultural approach which aims to diminish the emphasis on palaeopathology and its so-called clinical approach and to focus more on the general health of the populations under consideration. Even in this reduced role, however, palaeopathology will provide an essential framework for the study of health in a population as correct diagnosis is the basis of population or epidemiological studies.

Palaeopathology is the study of all diseases which may be found in an ient human remains; but we have chosen to on nlrat on t·h . ln Rifi ation of joh1.t diseases because these

1 r{· Hw OtH'H l'lw t t ll'h<wH know n bout l·h moRt and th y ar also


by far the most commonly found in the skeleton. In this final chapter we would like to make some general comments which are pertinent both to the bone specialist and to the archae-ologist. These comments come under three main headings: diagnosis, interpretation and epidemiology.

DIAGNOSIS

When starting to examine human bones and seeking a diagnosis for the joint changes which may be seen, there is an almost instinctive tendency to turn to a clinical textbook for help and guidance. If that fails then the second step may be to consult a textbook of radiology. There is a great likelihood, however, that neither will be very helpful for reasons which we have mentioned in earlier chapters, but which we now wish to reinforce.

Diagnosis in clinical practice is a means to an end-the end being treatment of a patient's symptoms-and not an end in itself. In palaeopathology, on the other hand, the diagnosis is the end, as there is nothing more that palaeopathologists can do other than say what conditions their subjects were afflicted with at the time of their death. And in arriving at a diagnosis, the clinician and the radiologist use methods which differ in kind very much from those which are available to the palaeopathologist. We can illustrate these differences most clearly by reference to OA.

For the clinician, the diagnosis of OA relies very heavily on the patient's complaint of pain in a joint perhaps supplemented by clinical signs such as swelling around the joint or crepitus on movement. But, put simplistically, a middle-aged patient who has pain in his hip has OA until proved otherwise. For the radiologist, on the other hand, the cardinal signs of OA are joint space narrowing, indicating degradation of the articular cartilage, and the presence of marginal osteophyte. In the large population studies of the prevalence of OA which Lawrence and his colleagues carried out in England in th 1 r.::o and 1960 , and oth r authors have 11nd rtc ken ciH(·wh •t'<•1 th •

Implications for Archaeologists 99

presence of OA has been determined on the basis of these radiological signs.

Palaeopathologists need no reminding that none of these clinical or radiological diagnostic criteria is available to assist them in their task-except for the presence of marginal osteophyte, but radiology is never needed to confirm what can be seen much better by the naked eye. To arrive at their diagnosis, then, palaeopathologists must rely on criteria which, although they must have a grounding in the clinical science of rheumatology, nevertheless are specific to their discipline. In the case of OA, there is one obvious sign on the joint surface which infallibly indicates the presence of the disease, and that is eburnation. Eburnation occurs only in a joint in which the articular cartilage has disappeared, leaving areas of bare bone to rub against each other. There is no dispute that eburnation allows OA to be diagnosed with absolute certainty, but where it is not present then we have suggested other criteria (see Chapter 4) which may be used instead. We have thus proposed what the epidemiologists would call an operational definition of OA for palaeopathologists to use. If it were to gain universal acceptance, then this would ensure that the diagnosis of this most common disease in the skeleton enjoyed some com-monality which it does not have at present, judging from a reading of the literature.

The reader will have noted that nowhere in this discussion do we mention the contribution which pathologists make to the diagnosis of joint disease in the skeleton. Since we describe the process of determining disease in bones as palaeopathology, it might seem strange that modem pathology has so little to offer. The explanation has to do with the nature of contemporary pathology which is based on cellular or subcellular rather than gross appearances, and in this respect palaeopathologists have more in common with the pathologists who worked before the advent of the microscope.

Th re is a need for some agreement on operational definitions of th j int di as other than OA, although this is a much more diffic11 lt tnHk, I ut it Hhou ld not be shirked merely on that t< '<'Ottnl. 11 i ' lnqmrlnnt th 11 o nw <or H('nAUH iH r a hcd flR to


which signs in the skeleton really are the result of diseases such as RA, otherwise the disagreement and argument which are found in the scientific press at present will continue to the detriment of palaeopathology as a whole. We have gone some way towards arriving at some definitions and we hope that we may be able to present them elsewhere in the future. Clearly, without some consensus of what constitutes, say, AS or DISH, in the skeleton, there will be great opportunity for error and this will distort any estimates of prevalence; this applies particularly with the less common joint diseases, where mis-diagnosis in a small number of cases may lead to large errors in the apparent relative frequencies between populations.

The importance of agreed diagnoses cannot be over-emphasised and discussions of the aetiology of disease, of its relative frequency and its cultural implications will be rendered meaningless unless different authors refer to the same entities in their work.

Although we have dealt with the most common and most reliably recognised joint diseases which are likely to be seen in the skeleton, it must be remembered that the classic appear-ances described here will not always be seen, especially where two or more diseases occur together; this may be confusing for the'beginner. It must also be borne in mind that an explanation will not be found for every single lesion. There are very many conditio:ris other than those mentioned here that may affect the joints; these include, for example, trauma, congenital dislocation of the hip, juvenile arthritis, acromegaly, rickets, osteoporosis, thyroid disease, hypertrophic osteoarthropathy, Paget's disease; the list, if not endless, could be extended for several more lines. Failure to diagnose a case is often more to do with the protean nature of joint disease than with the competence of the examiner; this may be a comforting thought to those struggling in vain to fit a name to a lesion.

INTERPRETATION

Those who examine the bones of their anc stors f 1 an understandable urge to xplain what th y fin ; th re iH

Implications for Archaeologists 1 01

feeling that each lesion must have its cause and that once this is known, this will throw light on the way of life of the individual concerned. The interpretation of the observations which they make is, of course, an important aspect of any palaeo-pathologist's work but often-all too often-the conclusions which are made outstrip the evidence and we would like to urge caution in one or two areas in relation to joint disease.

The severity of lesions

Many authors writing in respect of OA in particular, refer to the severity of the lesions, referring generally to the degree of marginal osteophyte. The thinking is that the larger the lesion, or the more extensive, then the more severe the disease. Alternatively, a more severe lesion may be considered to be a later stage in the disease than one which is milder.

Neither of these notions has any basis in clinical practice nor ) are they epidemiologically sound as we hope to show.

Taking the clinical point first. We assume that when authors consider a lesion to be severe then they assume that it had more impact on the individual during life than one which they deem to be less severe. This is a completely unfounded notion. As we have said, patients report to their doctors complaining of pain in a joint or some other symptom, and the degree of pain bears very little relationship to either the X-ray findings or to the morphological appearances which may be observed in a postoperative or autopsy specimen. For example, a patient who complains of severe pain in the knee may have a normal X-ray (Figure 11.1) and postoperative specimens following knee replacement may show little other than a small amount of eburnation or marginal osteophyte on one or other of the tibial plateaux (usually the medial in practice). Similarly, we have seen femoral heads that have been removed during hip replacement and show no change at all in their macerated state, which we would have considered normal had we encountered th 1n fr m , n or hn ologi al sit .

'C HI VI' I'H' I 1 flol'id \'1)111)\l' 111 y lW cf jA OVCl'<'d in fl joint wh n i t

I r

l ~


Figure 11.1 Radiograph of knee joints from a patient with clinical osteoarthritis. Note that the radiographic appearances are normal, although

the patient was in considerable pain

is in the field of an X-ray being taken for some other purpose. These may include joint space narrowing, sclerosis and marginal osteophyte, and yet the patient has no symptoms referrable to that joint (see Figure 11.2).

Clinical experience, therefore, shows that the correlation between the appearances of a joint, either radiologically or morphologically, and an individual's symptoms is poor and attempts to judge the magnitude of symptoms-the severity of disease-from the appearances of a joint are wasteful and can serve no useful purpose.

The attempt is often made to place lesions seen in a skeletal sample in a progression based on their severity- generally some aspect of their morphology, such as their size, so that some inference can be drawn about the natural history of the disease. We feel that this, too, may lead to error. We can illustrate this point by reference to a simple model. In Figure 11.3 we have shown the progression of a lesion- let us suppo that it is marginal osteophyte around the kn joint in A- in three individual , p, q and r. Th s v rily of th ir lcHion (in lhi

Implications for Archaeologists 103

Figure 11.2 Radiograph of the hips in a modern patient. Although the patient had no pain, there is radiographic evidence of osteoarthritis, especially on the

left-hand side

case, the extent to which the osteophyte develops) increases in each of the three at different rates, which is perfectly consistent with clinical observation. Let us further suppose, however, that each dies at a different time in the development of their disease; p dies at time a, r at time b and q at time c. The palaeo-pathologist now examines their skeletons and notes the severity of the lesions which are a', b111 and c". Using the standard approach under these circumstances, he/ she will grade them in order of severity as:

b"'--+ a'-+ c"

whereas reference to the figure will show that the temporal relationship is incorrect and that the severity of none can be used to predict the severity of the others, which is what one would hope to be the case if one were trying to determine the nalural hi tory f th di ease.

In pni:W!)J nlhology wt> hnvt• no ml'nns of knowing , t wh. t tl ltgt' in 111 11d v d11 tl 't diH•II t• lh tl individt l I dit•N, nor of

1 1


c 0 'iii (]) -0

~ ·;:: (]) > (])

(J)

b'

a' . bu - -QJ

c'

p

cu

q

Figure 11.3 Progression of hypothetical lesion in three cases, p, q and r. Assume that p dies at time a, rat time b and q at time c, then the presumed order of severity will be given as b"', a', c", although, in fact, this temporal

relationship is incorrect

knowing the rate of progress of that disease. That is to say, we do not know-in the case in point-whether an individual skeleton is like p, q or r in respect of the speed of development of the lesion, or if he/she died at a, b or c. The problem is well recognised in epidemiology and it is that one cannot make inferences about a dynamic process from a series of stati observations; to be able to do so r quir s that individuals an b follow d up ov r tim . How v r, in r· I. o nth lopy, we . re

Implications for Archaeologists 1 OS

able only to make cross-sectional observations. And that is a problem which no amount of tinkering with the data can overcome.

Occupation and activity

The final inference we would like to discuss briefly relates to occupation. It is a widely held belief that the distribution of OA in a skeleton can be used to predict the occupation or activity of the individual. We recognise that this is a perfectly laudable attempt on the part of palaeopathologists and anthropologists to extract the maximum amount of information from the rather meagre amount of data at their disposal, but it is mistaken. If we refer back to Figure 4.1 we can see that there are several factors which determine the development of OA; these include age, sex, race, genetic disposition and activity. Now in no case could one start with a skeleton which shows the presence of OA and say with any confidence which of the aetiological factors was responsible for the development of its disease. Moreover, even if we could be sure that activity were the prime mover, how would it be possible to say what activity was the cause?

Let us pursue this a little further with a consideration of OA of the hip. We know from recent epidemiological work that farmers are much more likely to develop this condition than the general population; their risk is approximately nine times that of the general population. If we encountered OA of the hip in a male skeleton it is reasonable to consider whether he might have been a farmer. However, although farmers are more at risk of getting OA of the hip, they are by no means the only people in whom it appears and if there were five male skeletons with OA of the hip (see Figure 11.4), only one of whom really was a farmer during life, there is no way at all by which we could say which he was. In Figure 11.4 we have shown the farmer as the shaded figure of the five, but we have no m ans at our disposal by which we can determine which he is; H'w nowA in th diagram ar all unidir tional, and . o it i. In 1 ~ t1 " '"I, llholog ; nil our nrrOW H 1 oin t fr'Oi11 ouR' to (•ffN :t,


Figure 11.4 Diagram showing five males who develop osteoarthritis of the hip. One (shaded) is a farmer, but there is no means whereby palaeopathologica l examination of the bone will determine which hip came from the farmer and so

any inferences made regarding occupation from the joint will be erroneous

we cannot reverse them and go from effect to cause, which is so often the direction in which the bone specialist seems so desperate to go.

The only possibility of safely inferring the occupation of an individual skeleton from the pattern of OA would b if that pattern were unique to one occupation, and, of o n, , w know that this is not th case. Th sam.c nrgurncnt nppl it•

Implications for Archaeologists 1 07

when occupation or activity is inferred from any other skeletal attribute; unless it is unique to that occupation, it has no predictive value.

On a population basis, however, it is permissible to make some inferences. For example, if in two populations the prevalence of OA of the hip was markedly dissimilar, and if one knew that the pattern of activity was different in the two groups-if one was rural and one urban, for example, then it would be reasonable to infer that the differences in activity were related to the variation in the expression of OA. Even then it would be a probability and not a certainty.

EPIDEMIOLOGY

Some epidemiological points have been dealt with earlier and we do not wish to stress many more here. However, because it seems so often misunderstood, we must emphasise that the frequency of joint disease (or any other) in past populations can only be expressed in terms of its prevalence. A palaeo-pathological examination is, epidemiologically speaking, a cross-sectional study and thus can only be used to measure prevalence and it is always incorrect to talk about the incidence of a disease in palaeopathology.

In order to determine the prevalence, however, it is necessary to take care about the denominator data, for it is only rather rarely that the total number of skeletons in an assemblage will be the denominator used to determine prevalence. As described in Chapter 2, prevalence is a simple ratio of those with the disease to the total population at risk, but when dealing with joints the denominator, putting things simply, is the number of joints present, not the number of individuals. It is for this reason that w e have stressed, in Chapter 2, the necessity to keep a record of the total number of each type of joint.

11 0 A Field Guide to joint Disease in Archaeology

(b) Spinal sites

Present OA OP Fusion IVD SN LF Cl C2 C3 C4 CS C6 C7 T1

T2 T3 T4 T5 T6 T7 T8 T9 TlO Tll T12

L1

L2 L3 L4 L5

Sl OA = osteoarthritis; OP = osteophyte; SN = Schmorl's nodes; IVD = intravertebral di disease; LF = calcified ligamentum flavum.

General Bibliography

J. Baker & D. Brothwell, Animal Diseases in Archaeology, London, Academic Press, 1980.

D.R. Brothwell, Digging up Bones, 3rd edition, London, Oxford University Press, 1981.

J.H. Klippel & P.A. Dieppe, Rheumatology, London, Mosby, 1994. D.J. McCarty & W.J. Koopman, Arthritis and Allied Conditions,

Philadelphia, Lea & Febiger, 1993. D.J. Ortn.er & W.G.J. Putschar, Identification of Pathological Conditions in

Human Skeletal Remains, Washington, Srnithsonian Institution, 1981. D . Resnick & G. Niwayama, Diagnosis of Bone and Joint Diseases, 2nd

edition, Philadelphia, W.B. Saunders, 1988. P.A. Revell, Pathology of Bone, Berlin, Springer-Verlag, 1986. C. Wells, Bones, Bodies and Diseases, London, Thames & Hudson, 1964.

Further Reading

CHAPTER 2

J. Rogers, T. Waldron, P. Dieppe & I. Watt, Arthropathies in palaeopathology: the basis of classification according to most probable cause, Journal of Archaeological Science, 1989, 16, 611-625.

T. Waldron, Counting the Dead. The epidemiology of skeletal populations, Chichester, John Wiley & Sons, 1994.

CHAPTER 3

S. Ahlback, Osteoarthrosis of the knee. A radiographic investigation, Acta Radiologica, Supplementum 277, 1968.

CHAPTER 4

P. Dieppe, Osteoarthritis. A review, Journal of the Royal College of Physicians, 1990, 24, 262-267.

J. Rogers & P.A. Dieppe, Ridges and grooves on the bony surfaces of osteoarthritic joints, Osteoarthritis and Cartilage, 1993, 1, 167- 170.

J. Rogers & P.A. Dieppe, Is tibiofemoral osteoarthritis in the knee joint a new disease? Annals of Rheumatic Diseases, 1944, 53, 612- 613.

J. Rogers, T. Waldron & I. Watt, Erosive osteoarthritis in n m di vnl skeleton, International Journa.l of Osteoar ha olo8y, 19 1, 1, 1 ')1 1 3.

Further Reading 11 3

J. Rogers, I. Watt & P. Dieppe, Arthritis in Saxon and medieval skeletons, British Medical Journal, 1981, 283, 1688-1670.

J. Rogers, I. Watt, & P. Dieppe, Comparison of visual and radiographic detection of bony changes at the knee joint, British Medical Journal, 1990, 300, 367-368.

L.C. Vaughan, Osteoarthritis in cattle, Veterinary Record, 1960, 72, 534-538.

H.A. Waldron, Prevalence and distribution of osteoarthritis in a population from Georgian and early Victorian London, Annals of the Rheumatic Diseases, 1991, 50, 301-307.

T. Waldron, The distribution of osteoarthritis of the hands in a skeletal population, International Journal of Osteoarchaeology, 1993, 2, 213-218.

T. Waldron & J. Rogers, Inter-observer variation in coding osteo-arthritis in human skeletal remains, International Journal of Osteoarchaeology, 1991, 1, 49-56.

CHAPTER 5

J. Forestier & J. Rotes-Querol, Senile ankylosing hyperostosis of the spine, Annals of the Rheumatic Diseases, 1950, 9, 321-330.

H. Julkunen, O.P. Heinonen & K. Pyor~ila, Hyperostosis of the spine in an adult population, Annals of the Rheumatic Diseases, 1971, 30, 605-612.

T. Waldron, DISH at Merton Priory: evidence for a 'new' occupational disease? British Medical Journal, 1985, 291, 1762-1763.

T. Waldron & J. Rogers, An epidemiologic study of sacroiliac fusion in some human skeletal remains, American Journal of Physical Anthropology, 1990, 83, 123- 127.

CHAPTER 6

P. Hacking, T. Alien & J. Rogers, Rheumatoid arthritis in a medieval skeleton, International Journal of Osteoarchaeology, 1994, 4, 251-255.

B.H. Rothschild, K.R. Turner & M.A. DeLuca, Symmetrical erosive peripheral polyarthritis in the late archaic period of Alabama,

ien e, 198 , 241, 1498-1501. T. W~t ld mn, J. Rog rs & I. Watt, Rheumatoid arthritis in an En li h

•n••d ••v tl lt•h·lo••, l llli'rnal ional Joumal of steoar haeolo&y, 1 4, IJ., 1!1 11 111'/

114 Further Reading

CHAPTER 7

J. Rogers, I. Watt & P. Dieppe, The palaeopathology of spinal osteophytosis, vertebral ankylosis, ankylosing spondylitis and vertebral hyperostosis, Annals of the Rheumatic Diseases, 1985, 44, 118- 120.

CHAPTER 8

P.A. Dieppe & J. Rogers, The Antiquity of the Erosive Arthropathies, Conference Proceedings No. 5, Arthritis & Rheumatism Research Council, 1988.

CHAPTER 9

C. Wells, The human burials. In: Romano-British Cemeteries at Cirencester, edited by A. McWhirr, L. Viner & C. Wells, Cirencester, Cirencester Excavation Committee, 1982, pp. 135-196.

CHAPTER 10

J. Rogers & T. Waldron, Infections in palaeopathology: the basis of classification according to most probable cause, Journal of Archaeological Science, 1989, 16, 611 - 625.

D. Morse, D.R. Brothwell & P.J. Ucko, Tuberculosis in ancient Egypt, American Review of Respiratory Diseases, 1964, 90, 524- 541.

A. Stirland & T. Waldron, The earliest cases of tuberculosis in Britain, Journal of Archaeological Science, 1990, 17, 221 - 230.

CHAPTER 11

H . Bush & M. Zvelebil, Health in Past Societies, Oxford, BAR, 1991.

Index

Alibert, J.L., 70 Ankylosing spondylitis, 5, 64-9,

100 characteristics of, 68 diagnosis of, 66- 8 esthesopathy in, 64, 68 HLA-antigens in, 64, 68 in animals, 64 kyphosis in, 67 pathology, 65-6 prevalence of, 64 radiography in, 65- 6, 68

bamboo spine, 65, 68 sacro-iliitis in, 64, 65- 6 skip lesions in, 66 vertebrae in, 65- 6

Annulus fibrosa, 24 Arthritis, see joint diseases Arthritis mutilans, 71, 75 Articular cartilage, 1, 8

!31rH;torny si , 95 )ltl lll ' fol'llwr , , 4 lltllt 'l' lh t 1 1):1 /) l llld 11 11 Ill

Calcium pyrophosphate, 36 Coccidioidomycosis, 95

Degenerative disc disease, 26-7

osteophytes and, 27 Diagnosis in palaeopathology,

98- 100 Diffuse idiopathic skeletal

hyperostosis, see DISH DISH, 36, 47- 54, 67-8, lOO

at Merton Priory, 48 at Wells Cathedral, 48 bone formers and, 53 characteristics of, 54 diagnosis of, 51- 3 entheses in, 49-50 marginal osteophytes and,

53 pathology, 48- 51 prevalence of, 48 radiology of, 50 sacro-iliac fusion in, 52

DIP, 8 in psoriatic arthropathy, 71 in rh umatoid c rthriliH, , o. ll 'OJ h to, L of, 0

116 Index

Distal interphalangeal joints, see DIP

DNA, 96

Eburnation, 13, 35-6, 43, 99 in osteoarthritis, 13 in rheumatoid arthritis, 57 pathognomonic of

osteoarthritis, 43 Enthesopathy, 42

in ankylosing spondylitis, 64, 68

in DISH, 48-9 rotator cuff disease and, 42

Enthesophytes, 24-5 in DISH, 52

Erosions, 11, 12 in gout, 79 in psoriatic arthropathy, 73 in Reiter's disease, 74 in rheumatoid arthritis, 58-62 in sero-negative

spondylarthropathies, 70 marginal, 12

Exostoses, 23

Forestier, J., 47

Gout, 3, 78-82 characteristics of, 83-4 diagnosis of, 80-1 erosions in, 79 of MTP, 78 radiology of, 80-1

Martell hook, 80 tophi, 79 uric acid in, 78, 81, 83

Gumma, 86

Hallux valgus, 82 HLA-antigens, 56, 64, 68

Impingement syndrome, 42

Joint capsule, 1 Joint(s)

cartilaginous, 1 compound, 14, 42-3 counting and recording, 8-11 diseases, 2

acute, 3 atrophic, 3 classification of, 4, 8-15 chronic, 3 diagnostic criteria for, 4 hypertrophic, 3

fibrous, 1 infections of, 87-96 pathology

classification of, 15 recording forms for, 10 patterns of skeletal

involvement in, 6-7 structure of, 1 synovial, 1

Julkunen, H., 48 Juxta-articular area, 2

Knee joint, 42 compartments of, 42 osteoarthritis of, 41, 42-2

Landre-Beauvais, A.J., 55 Lawrence, J.S., 98 Leprosy, 71, 94

Martell hook, 80

Metatarsal pitting, 30 Metatarso-phalangeal joint, see

MTP MTP

hallux valgus of, 80 in gout, 78 in rheumatoid arthritis, 56 in psoriatic arthropathy, 71

Mushroom head, of femur, 38, 41 Myositis ossificans, 23

Odds ratio, 19 Odontoid peg, 20, 46 Ossification, 24

into anterior longitudinal ligament, 24

paravertebral, 25 Osteoarthritis, 3, 26, 32-47, 98

atrophic, 36 at the shoulder joint, 40, 42 at unusual sites, 33 calcium pyrophosphate crystals

and,36 changes in joint contour and,

38 characteristics of, 45 classification of, 43-5

criteria for, 43-5 common sites of, 32 complicating other diseases,

36-7 eburnation in, 35, 43-4 erosive, 33-4

gull-wing appearance in, 33 grooving of joint surfaces in,

36- 8 hyp rtrophic, 35, 45, 53 in onirna ls, 34- 5 joint· difl lc Lion , nd, 37 occ ttp lllo tt ttttl , ((),) 7 of odtHtlt~ d fi' ')',, '~'' ell lftt • h l' r l01c '/

Index

of the knee joint, 42-3 osteophytes and, 15 pathology of, 35-6 prevalence of, 44, 98

117

radiology of, 37-40, 43, 101-2 joint-space narrowing, 43 sclerosis, 37 sub-chondral cysts, 37

rheumatoid arthritis and, 36 severity of, 101-5 trauma and, 36

Osteoblasts, 8 Osteochondritis dissecans,

28-30 location of, 28-9

Osteoclasts, 8, 12, 13 Osteomyelitis, 87-9, 90

cloacae in, 88 diagnosis of, 95 features of, 93 involucrum in, 88 new bone formation in, 88

Osteophytes, 20-31, 66 bicipital groove and, 42 causes of, 26 characteristics of, 31 degenerative disc disease and,

27 distribution of, 20 marginal, 21, 30, 44

classification of osteoarthritis and,44

in DISH, 53, 68 morphology of, 20-2 of DIP, 20 of odontoid peg, 20 of PIP, 20 osteoarthritis and, 25 rating scales for, 21 -2 s v rity of, 21 Hignifi 011 f, 2r: - 6 lruttnlll nnd, 23 Vt•l'lc• lll' d, ' ()

I Ill Index

Ost oporosis, 13-14, 93, 100 in sero-negative

spondylarthropathies, 70 in rheumatoid arthritis, 57

Pigmented villonodular synovitis, 82, 85

PIP, 8 in psoriatic arthropathy, 71 in rheumatoid arthritis, 56 osteophytosis of, 20

Pott's disease, 91, 96 Prevalence, 15, 107

age-specific, 17 calculation of, 16-17 comparison between groups,

18 crude, 18 definition of, 16 of DISH, 48 of osteoarthritis, 4 of rheumatoid arthritis, 55 sex-specific, 17

Proliferation, 11 in psoriatic arthropathy, 73 in sero-negative

spondylarthropathies, 70 rating scales for, 11

Proximal interphalangeal joints, see PIP

Pseudo-erosions, 30, 61, 63 Psoriatic arthropathy, 66, 69,

70- 3 arthritis mutilans, 71, 75 diagnosis of, 74- 7 distribution of, 71 - 2 erosions in, 73 prevalence of, 70 proliferation in, 73 radiology in, 71, 73

cup and pencil deformity, 71

sacro-iliitis in, 72 spinal fusion in, 72

Pyogenic arthritis, 88 characteristics of, 96

Radiography in ankylosing spondylitis, 65-6 in DISH, 50 in osteoarthritis, 14, 37-40 in psoriatic arthropathy, 71 in Reiter's disease, 76 in rheumatoid arthritis, 61

Rating scales for osteophytes, 21-2 for proliferation, 11

Reiter, H., 73 Reiter's disease, 66, 69, 73 - 7

diagnosis of, 74- 7 enthesis in, 75 erosions in, 7 4 radiology of, 76 sacro-iliitis in, 74 skip lesions in, 74-5

Resnick, D., 47 Rheumatoid arthritis, 3, 36, 53,

55- 63, 69-70, 100 characteristics of, 63 diagnosis of, 58- 63 distribution of affected joints,

56- 7 eburnation in, 57 erosions in, 58- 62 HLA-antigens and, 56 osteoarthritis in, 36 osteopaenia in, 57 pathology of, 56- 8 prevalence of, 55 radiology in, 61 rheumatoid factor (RF) in,

57-8, 62 sacro-iliac joints and, 57 synovial m mbranc in, 5 1

Rheumatoid factor, 57, 62, 69 Ring-bone, 34 Risk ratio, 19 Rotes-Querol, J., 47

Sacro-iliac joints, 52-3, 65-6 in ankylosing spondylitis, 64 in psoriatic arthropathy, 72 in Reiter's disease, 74 in rheumatoid arthritis, 57

Scheuermann' s disease, 27 Schmorl's nodes, 27, 93 Sclerosis, 37 Skeleton, recording forms for, 10 Skip lesions, 65- 6, 74-5 Spavin, 35 Spondylarthropathy, 3

sero-negative, 3, 69- 77 characteristics of, 77 pathology of, 70

Spondylolysis, 52 Sub-chondral cysts, 37 Synovial chondromatosis, 82, 85

Index 11 9

Synovial membrane, 1, 8 in rheumatoid arthritis, 57 in sero-negative

spondylarthropathies, 70

Tuberculosis, 89-93 bacterial DNA in, 96 characteristics of, 96 in the fingers, 91 in the spine, 90 of the joints, 92

Tuberculous arthritis, 92 dactylitis, 91 diagnosis of, 95-6 discitis, 92-3 features of, 93

Uric acid, 36, 78, 81, 83

Wells, C., 79 Wood Jones, F., 55

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