Orthopaedics - Ningapi.ning.com/files/lpTJaTQR7WKcobpnFoU9Q9a6...Osteoarthritis (OA) of the knee joint is the single most important aetiological factor causing disabil-ity in adults

Unicompartmental Knee Arthroplasty

Management of Osteoarthritis of Knee

High Tibial Osteotomy: Current Status in

Dr. Aditya Soral, Dr. Rajesh Malhotra

TODAY

OrthopaedicsJuly-September 2009 Vol. XI No.3

Editor | Dr. Rajesh Malhotra

Dr. Vijay Kumar, Dr. Rajesh Malhotra

ViscosupplementationViscosupplementation in Osteoarthritis of Knee

HTO

Dr. Amite Pankaj

UKA Virtual Reality in MedicineThe Uses and Benefits of Virtual Reality in Medicine

Dr. R Rambani

Index

89

EditorialAdvances in Imaging of Cartilage – “Visualising”the Glycosaminoglycans : Rajesh Malhotra : 92

ViscosupplementationViscosupplementation in Osteoarthritis of Knee:

Aditya Soral, Rajesh Malhotra : 94

HTOHigh Tibial Osteotomy: Current Status inManagement of Osteoarthritis of Knee:

Amite Pankaj : 99

UKAUnicompartmental Knee Arthroplasty:

Vijay Kumar, Rajesh Malhotra : 105

Virtual Reality in MedicineThe Uses and Benefits of Virtual Reality in Medicine:

R Rambani : 113

VOL XI No 3 : July-September 2009

�


Orthopaedic EquipmentKnow your Equipment: Wound Drain:

Dharmesh Khatri, Vijay Kumar, Rajesh Malhotra : 118

Complex TraumaMetadiaphyseal Fractures of the Distal Radius –Managed by Stacked Plating :M Shantharam Shetty, M Ajith Kumar, Jagadish Prabhu : 122

Pioneers in OrthopaedicsPioneers in Orthopaedics : Bhavuk Garg, Rajesh Malhotra : 124

Ortho QuizOrtho Quiz-20 : Bhavuk Garg, Rajesh Malhotra : 125

Answer and Discussion to Ortho Quiz-19 :

Bhavuk Garg, Rajesh Malhotra : 126

Managing Director : Venkatraman K

Editor : Rajesh Malhotra

Editorial Advisory Board: Abrar Ahmed, Ajoy K Sinha,Ashok N Johari, Bhavuk Garg, GS Kulkarni, HN Sinha,Jaswant Rai, Mayil Vahanan Natarajan, Mohd. Farooque, PKDave, S Bhan, S Venkat, SC Goel, SKS Marya, SM Tuli,Sushrut Babhulkar

Desk Editor : Garima Singhal

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Publisher's Information


Dr. Rajesh MalhotraProfessor

Deptt. of OrthopaedicsAll India Institute of

Medical SciencesNew Delhi

editorial �

Advances in Imaging ofCartilage – “Visualising” theGlycosaminoglycans

S ensitive and non invasive measures are important for understanding disease processes and

the development of therapeutics. Though not always perfect, the presently available

measures (for example DEXA for Osteoporosis) have a profound impact on our understand-

ing of the physiology and pathophysiology of the particular organ system and subsequent

development of preventive and therapeutic strategies. However, in the field of osteoarthritis, there

are hardly any assays that can be used in clinical research or practice to provide insight into early

cartilage degeneration. Accordingly, considerable effort has been made to develop biomarkers for

cartilage degeneration and regeneration which have been used in experimental settings to study

the effect of disease modifying agents on osteoarthritis.

There has been a body of work, done in Boston, Massachusetts, surrounding the development

of Magnetic Resonance Imaging (MRI) techniques for non invasively imaging the glycosaminoglycan

(GAG) concentration of articular cartilage. GAG makes up about 5% of cartilage volume by weight

(or 20% of solid volume) and is a constituent of the proteoglycan macromolecule. GAGs are repeating

disaccharides with carboxyl and sulfate moieties that are charged under physiological conditions.

These GAG chains are so densely packed that the concentration of negative charge can be as much

as 150mM to 300mM in normal articular cartilage. Because these charges are integral elements of

the GAG molecule, they are fixed to the solid matrix. Thus, in contrast to the mobile ions in the

extra cellular fluid, these molecules are referred to as fixed charge, and the concentration of this

fixed charge is called the fixed charge density (FCD). Nearly every method of measuring GAG is

a measure of electrical charge of the extra cellular matrix. These include radiotracer method, histologic

staining with cationic dyes, biochemical assays, and MRI-based methods. Abundant evidence exists

that diseased cartilage is lacking in GAG (and the associated charge) and that the mechanical

properties of cartilage are strongly influenced by the concentration of GAG or charge.

MRI is an ideally suited technology for measuring FCD in cartilage because it nondestructively

measures the concentration of an ion in tissue and because it provides spatial maps or images.

93VOL XI No 3 : July-September 2009

MRI methods for measuring FCD, sodium-MR and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC)

both involve visualising the distribution of a specific mobile ion [Na+ ] and Gd(DTPA)2, respectively.

Gd(DTPA)2- (Magnevist; Berlex, NJ) is a clinically approved MRI contrast agent. These MR-based methods

can provide a map or image reflecting GAG concentrations. This has been demonstrated in vitro using

MR measurements of the cation Na+ by sodium MR spectroscopy and imaging and of the divalent anion

Gd(DTPA)2- using proton MRI spectroscopy and imaging. Latter technique has comparatively high

resolution and sensitively with reasonable straightforward implementation on standard MRI instruments.

Sodium MRI on the other hand, provides less resolution and is not generally available on standard clinical

MRI instruments. That dGEMRIC measures FCD and GAG has been validated in vitro against several

standard methods. In vivo images of cartilage taken before total joint arthroplasty have been found to

be similar to the corresponding in vitro images and histology of the tissue harvested during surgery.

The advent of methodology to measure FCD (and hence indirectly GAG) non destructively on a spatially

localised basis enables a number of in vitro and in vivo applications of dGEMRIC that are providing new

insights into cartilage physiology, disease progression, and preventive or repair strategies. One can track

the distribution of GAG across the cartilage over time in culture during in vitro studies with high resolution

thereby enabling long-term studies of the evolution of degradation, development, or repair and of factors

that might be involved in these processes.

Several in vivo studies utilising dGEMRIC have already provided valuable clinical insights into human

joint physiology and disease. The dGEMRIC index (T1 measurements in in vivo studies of dGEMRIC)

of knee cartilage in healthy volunteers has been shown to correlate with the level of physical activity.

Much of our understanding of osteoarthritis is limited because of the lack of a sensitive measure of early

disease. The current gold standard is the plain radiograph, which has poor correlation to symptoms and

which is sensitive only in later stages of the disease (after tissue loss and bony changes have occurred).

In many instances, large variation in dGEMRIC was observed even when no joint space narrowing was

observed on radiographs, presumably identifying areas of biochemical degradation preceding the actual

loss of tissue.

In conclusion, MRI has the potential to provide information regarding the molecular state of cartilage in

both bench and clinical studies. The dGEMRIC technique, as a measure of GAG distribution, demonstrates

good correlations with known biochemical and biomechanical properties of the tissue. Furthermore, the

dGEMRIC index has demonstrated measurable and reproducible changes with physiologic and pathologic

processes. Indeed, these revolutionary studies, that would have been impossible a decade ago, have

brought us on to the leading edge of a paradigm shift, where rather than focusing on the late stage of

disease with palliative therapy, we can recognise early degenerative changes and intervene with appropriate

preventive and disease-reversing therapies.


Osteoarthritis (OA) of the knee joint is the singlemost important aetiological factor causing disabil-ity in adults. In an epidemiological study,1 out ofa total of 3,266 people the prevalence ofosteoarthritis of the knees was found to be 7.1%.The primary goals of treatment in this conditionare to minimise pain, maintain and improve jointmobility and to minimise functional impairment.2

The role of viscosupplementation in osteoarthritiscomes into play when the initial non operativetreatment (physical therapy, weight loss, bracingand pharmacologic agents) is rendered ineffectiveor is not tolerated.3 This review is aimed atdiscussing few issues associated withviscosupplementation.

WHAT IS VISCOSUPPLEMENTATION?

The term “Viscosupplementation” was introducedby Dr. Endre Balazs, referring to the concept ofsynovial fluid replacement with intra-articular in-jections of hyaluronic acid.4 Synovial fluid in ahealthy joint is the prime factor responsible for

acting as a shock absorber as well as a lubricant.These basic functions of the synovial fluid areimparted to it by the presence of hyaluronan.Hyaluronan are simple polysaccharides composedof repeating disaccharide units of n- acetyl galac-tosamine and glucuronic acid.4

SYNOVIAL FLUID AND ITS ALTERATION IN OA

Synovial fluid is an ultradialysate of blood plasmato which proteoglycan has been added by localsynthesis by the joint tissues.5 The molecularweight of hyaluronan in normal synovial fluid is inthe range of 6000-10,000 Kd.6,7 This hyaluronanwhich is produced by type A synoviocytes isresponsible for the rheologic properties of thesynovial fluid. Hyaluronan acts as a lubricantwhen movements are slow and as a shock ab-sorber when they are fast.8 In osteoarthritis, theconcentration and molecular weight of hyaluronanin synovial fluid is diminished due to dilution,fragmentation and production of low molecularweight hyaluronan by the cells.9 This realisationof facts led to the proposition that removal ofpathologic joint fluid and replacement with exog-enous hyaluronan and its derivatives can benefitthe patients, giving rise to the concept ofviscosupplementation.8

Viscosupplementation inOsteoarthritis of Knee

ADITYA SORAL

Junior Resident

RAJESH MALHOTRA

Professor

Deptt. of Orthopaedics

AIIMS, New Delhi

ABSTRACT

The role of viscosupplementation in osteoarthritis comes into play when the initial nonoperative treatment (physical therapy, weight loss, bracing and pharmacologicagents) is rendered ineffective or is not tolerated. In osteoarthritis, the concentrationand molecular weight of hyaluronan in synovial fluid is diminished due to dilution,fragmentation and production of low molecular weight hyaluronan by the cells.9 Thisrealisation of facts led to the proposition that removal of pathologic joint fluid andreplacement with exogenous hyaluronan and its derivatives can benefit the patients,giving rise to the concept of viscosupplementation.

VISCOSUPPLEMENTATION

Keywords: Viscosupplementation,Osteoarthritis of knee, Hyaluronan, Synovialfluid, Hylans

“The primary goals

of treatment of

osteoarthritis are

to minimise pain,

maintain and improve

joint mobility and to

minimise functional

impairment”


MECHANISMS OF ACTION

The actual mechanism of action of hyaluronan(HAs) is still a topic of research with more and morenew literature being added day by day. The ben-efits imparted by exogenous HAs are mainly di-vided into two broad categories: Rheological andBiological.

RHEOLOGICAL EFFECTS

Exogenously introduced HAs immediately restorethe viscoelastic properties of the synovial fluid.As discussed earlier, under low shear load the HAmolecules line up and act as a viscous lubricant.Under high shear load condition they act as anelastic liquid or shock absorber by absorbingenergy and buffering the force transmitted acrossthe joint.10 Studies have also postulated that theHAs have a direct antinociceptive action.11 Theyare thought to form a protective covering over thenociceptors, preventing pain mediators from stimu-lating the nociceptors. Other rheological actionsinclude decreased mechanical sensitivity of stretchactivated ion channels.12

BIOLOGICAL EFFECTS

The duration of clinical benefit surpasses the resi-dence time of exogenously introduced HAs by a fairmargin. To explain this enhanced effect, numerousbiological mechanisms have been postulated. HAsof molecular weight greater than 100Kd seem toexert an anti-inflammatory effect within synovialfluid by inhibiting many activities of inflammatorycells. These actions of HAs are mediated throughmembrane proteins like CD 44.13,14 HAs have beenshown to reduce the levels of arachidonic acid, PGand leukotrienes in the synovial fluid.15 HAs alsohave been shown to antagonize the activity of IL-1beta16 and TNF- alpha.17

Sato et al18 demonstrated that HAs reduce theamount of reactive oxygen species. HAs demon-strate an antioxidant action in a molecular weightand a dose dependant manner. Production ofendogenous HAs is also facilitated by exogenouslyadministered HAs. This action is thought to bemediated through CD 44 receptor. Exogenouslyadministered HAs to the arthritic cell cultures hasbeen shown to increase the number of type Asynoviocytes and to the production of HAs ofnear normal HAs.19,20

VISCOSUPPLEMENTATION PRODUCTS

In the initial days, rooster combs and humanumbilical cords were used for production of

hyaluronan. Currently rooster combs and bacte-rial cultures are being used.21 The hyaluronanproduced is divided into two parts: an inflamma-tory and a non-inflammatory fraction. The non-inflammatory fraction is used therapeutically. Thecommercial products available in the market areclassified according to the molecular weight, rang-ing from low molecular weight hyaluronan to highmolecular weight hylans.

Hylans are chemically cross linked hyaluronandeveloped to improve the efficacy ofviscosupplementation treatment. The proposedmechanisms behind the claimed increased effi-cacy include:� Increased retention time,� Improved rheological properties and� Improved resistance to free radical degrada-

tion.

Hylan GF 20 (Synvisc®) is a mixture of hylan A (90%per weight) and hylan B (10% per weight). HylanA is a soluble molecule of native hylan and hylanB is a gel composed of a continuous molecularnetwork; these molecules are cross linked by theirhydroxyl groups.

Though the cross linked hylans are considered tobe superior to the low molecular weight, it is stilla matter of controversy as discussed later.

CLINICAL EVIDENCE OF BENEFIT

The clinical evidence regarding the efficacy ofviscosupplementation ranges from highly effec-tive to completely ineffective, however most of theclinical studies suggest that by and large thistreatment option is safe and effective.

Cochrane collaboration review22 on the topic ofviscosupplementation is so far the most detailedsystematic review. In this review, forty trials com-pared HA with placebo. HA as class was found tobe superior to placebo when the analyses of theeffects were pooled. In 10 trials, HA was comparedto IA steroids. HA as a class was found to have amore prolonged efficacy. On comparison withNSAIDs, HAs were found to have similar efficacywith more local side effects but less systemic sideeffects. In the final conclusion authors foundviscosupplementation to be a safe and effectivetreatment option.

Kolarz et al,23 performed a multicentre open- labelobservation study evaluating the long term ben-

“The molecular weight

of hyaluronan in

normal synovial fluid

is in the range of 6000-

10,000 Kd. This

hyaluronan which is

produced by type A

synoviocytes is

responsible for the

rheologic properties of

the synovial fluid”

“Exogenously

introduced HAs

immediately restore

the viscoelastic

properties of the

synovial fluid. HAs are

thought to form a

protective covering

over the nociceptors,

preventing pain

mediators from

stimulating the

nociceptors”


efits of sodium hyaluronate administered onceweekly for 5 weeks. Significant improvement werenoted with pain on movement and rest measuredby visual analog scale and Likert scale, walkingtime, knee function and global assessment ofefficacy. These changes were seen starting oneweek after the injection. Of the 108 enrolled pa-tients, 59 (55%) improved enough so that they didnot require a second injection cycle during the 12month study.

In another study,24 long term efficacy and safetyof five weekly IA injections of sodium hyaluronate(MW 500-730 Kd) was evaluated in patients withmoderate to severe knee OA in whom the pain wasnot controlled by conventional measures. Totalknee replacement surgery was avoided or signifi-cantly delayed in 15 of 19 patients who had con-sidered surgery before the injections.

FACTORS AFFECTING OUTCOME

Conrozier et al,25 identified certain factors whichhad significant association with good outcomefollowing HAs supplementation. These factorsinclude single compartment disease, moderateeffusion, lateral patellar injection and meniscalcalcinosis.

A few other studies26,27 have correlated poor out-comes with the presence of moderate or severeradiological changes of OA and presence of se-vere patellofemoral arthritis.

SIDE EFFECTS AND COMPLICATIONS

Mild injection site pain and swelling are the mostcommon adverse events associated with theiruse.4 In a large clinical trial, a series of five weeklyIA injections of HA was compared with placebo ororal naproxen in 495 knee OA patients.28 On evalu-

Table 1: Studies comparing low molecular weight hyaluronan with high molecular weight hylans

Researchers Type of Comparative No. of Results Commentsstudy groups patients

Wobig M, et al.34 Double blind Hylan GF20 Total=70 Significantly better Adverse effect rate:randomised (Inj Synvisc) Hylan GF20=38 results in all Hylan GF20= 1.8%control trial Sodium LMW HA=32 primary outcome LMW HA= 0.9%

hyaluronate measures viz: But statistically(LMW) � Weight bearing pain insignificant

� Most painful knee movement� Overall assessment of treatment

seen in the Hylan GF 20 group

Karartay S, et al.35 Randomised Hylan GF 20 Total= 40 No difference between the two ICAM 1 and VCAM 1control trial (Synvisc) groups with respect to: are inflammatory

LMW HA � ICAM 1 and VCAM 1 level mediatorsin synovial fluid

� WOMAC pain score� Stiffness score� Physical function score

Gomis A, et al.36 Animal study Synvisc (Hylan NA Synvisc significantly reduced The effect depends upon(rats) GF20) (by an average of 50%) the the degree of

Hyalgan impulse discharge in both normal “elastoviscosity”(LMW HA) and inflamed joints 50 minutes after of the HA product.and Orthovisc injection, and this level of impulse Synvisc has the(Intermediate discharge continued until the maximumMW HA) end of the recording period elastoviscosity

(120-130 minutes after injection).

Reichenbach S, et al.37 Systematic Hylan (Synvisc) Metaanalysis � Lack of evidence of superior Use of intra-articularreview and Hyaluronic of 13 trials with effectiveness of Hylan Hylan is discouragedmetaanalysis acid total of 2085 � Increased risk of local side in the metaanalysis

patients effects with Hylan

“Factors associated

with good outcome

following HAs

supplementation

include single

compartment disease,

moderate effusion,

lateral patellar

injection and meniscal

calcinosis”


ation, there was a lesser incidence of GI complaintswith HA as compared to naproxen but the injectionsite pain was significantly higher in the HAs groupcompared to the saline control group.

Severe acute inflammatory reaction or pseudosepsis is associated with the use of chemicallymodified hyaluronan, hylan GF20.29 Clinically thisreaction presents as septic arthritis but the cultureis negative. Patients presenting with this condi-tion have shown development of antibodies tochicken protein and hylan, indicating an immuno-logical basis for the reaction.30 The treatmentincludes rest, ice, oral anti-inflammatory medica-tions, knee aspiration and corticosteroid injec-tions.

Other rare side effects reported include episodesof pseudogout, calcium pyrophosphate dihydratearthritis, chronic granulation inflammation andpseudotumour formation.31

ISSUES OF CONTENTION

Viscosupplementation has been more or less ac-cepted as a safe and effective form intervention ofosteoarthritis of the knee. However, there arecertain issues which are associated with its use.

CAN WE GIVE REPEATED CYCLES?

Scali32 reported the use of repeated cycles ofsodium hyaluronate in a study. In this 30 monthstudy of efficacy and tolerability of repeatedcourses of treatment with HA every 6 months in75 patients, it was found that there was a 31%decrease in mean spontaneous VAS pain duringthe five treatment cycles. In the study, no localor systemic inflammatory reactions were re-ported.

Waddell et al,33 conducted a prospective openlabel study to evaluate the efficacy of a repeatcourse of hylan GF20 in patients who had alreadybenefitted from an initial course. The average timeuntil the second course was 19.6 months. Hesupported repeated use of HAs.

WHICH ONE IS BETTER?

As discussed earlier, the commercially availableproducts of HA range from low molecular weighthyaluronan to high molecular weight cross linkedhylans. Although as already described theoreti-cally the cross linked hylans are considered supe-rior, the clinical studies are not that conforming(Table 1).

CONCLUSION

Keeping in mind the safety profile of the HAproducts and their efficacy, the hyaluronan prod-ucts can be considered for treatment in patientsnot responding to other non surgical interven-tions. The groups of patients who will benefit themost by their use include those with mild radio-logical features of OA on the x rays.

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“Mild injection site

pain and swelling are

the most common

adverse events

associated with

�their use”

“Severe acute

inflammatory reaction

or pseudo sepsis is

associated with the

use of chemically

modified hyaluronan,

hylan GF. Clinically this

reaction presents as

septic arthritis but the

culture is negative”


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Products on Synovial Fluid Levels of Intercellular

Adhesion Molecule-1 and Vascular Cell Adhesion

Molecule-1 in Knee Osteoarthritis. Annals of

Clinical and Laboratory Sciences. 2004;34:330-

35.

36. Gomis A, Pawlak M, Balazs EA, et al. Effects of

different molecular weight elastoviscous hyaluronan

solutions on articular nociceptive afferents. Arthri-

tis and Rheumatism 2004;50(1):314-26.

37. Reichenbach S, Blank S, Rutjes AWS, Shang A,

King EA, Dieppe PA, et al. Hylan versus Hy-

aluronic acid in osteoarthritis of the knee. A

systematic review and metaanalysis. Arthritis and

Rheumatism 2007;57(8):1410-1418.


INTRODUCTION

High tibial osteotomy is based on the principlethat osteoarthritis, as opposed to the inflamma-tory arthritis, is primarily a mechanical problem inwhich cartilage degeneration occurs through ab-normal stresses and overload. It is therefore notunreasonable to think that correction of themalalignment can stop or slow this pathologicprocess. High tibial osteotomy (HTO) has been inpractice for decades as a treatment modality forosteoarthritis of the knee but its popularity hasdecreased over the years; primarily as a result ofsuccess of arthroplasty, total knee replacementand unicondylar knee replacement. However, therehas been renewed interest in HTO in last twodecades as the role of correction of malalignmentof the knee has been recognised in the treatmentof ligamentous injuries of the knee and its possiblerole in delaying development of osteoarthritis.1-3

High Tibial Osteotomy: CurrentStatus in Management ofOsteoarthritis of Knee

AMITE PANKAJ

Consultant Joint Replacement

and Arthoscopy Surgeon

Fellow Sports Medicineand Shoulder Surgery,WOC, Perth, Australia

Deptt. of OrthopaedicsGTB Hospital, Delhi

ABSTRACT

There has been renewed interest in HTO in last two decades as the role of correctionof malalignment of the knee has been recognised in the treatment of ligamentousinjuries of the knee and its possible role in delaying development of osteoarthritis.New techniques for medial-opening-wedge osteotomy and specially designedfixation plates based on the locking-compression-plate (LCP) concept, providingsuperior initial stability, are now available. Appropriate selection of patients and theachievement and maintenance of an adequate operative correction are required fora successful outcome.

HTO

Recently, better guidelines have been formulatedfor the selection of candidates for osteotomy byThe International Society of Arthroscopy, KneeSurgery and Orthopaedic Sports Medicine(ISAKOS).4 New techniques for medial-opening-wedge osteotomy and specially designed fixationplates based on the locking-compression-plate(LCP) concept, providing superior initial stability,are now available.5, 6, 7 The most important mes-sage which has emerged from retrospective stud-ies is that the appropriate selection of patients andthe achievement and maintenance of an adequateoperative correction are required for a successfuloutcome.

This article discusses the current role of HTO inmanagement of osteoarthritis of knee, patient se-lection guidelines, various technique of HTO andtheir comparative analysis, and TKA followingHTO.

SELECTION OF PATIENTS

Patient selection is critical to the success of kneeosteotomy, which may be considered for patientswith a high-demand, active lifestyle whose life

Keywords: High tibial osteotomy,Osteo-arthritis of knee, Medial openingwedge osteotomy.

“High tibial osteotomy

is based on the

principle that

osteoarthritis is

primarily a mechanical

problem in which

cartilage degeneration

occurs through

abnormal stresses and

overload”


expectancy exceeds the expected survival of aknee prosthesis.7 Stability of the knee and a func-tional range of motion are generally required for asuccessful osteotomy, and inflammatory arthritisand knee stiffness are generally contraindications.9

Instability due to anterior cruciate ligament insuf-ficiency can be corrected with reconstruction ofthat ligament. The reconstruction can be com-bined with osteotomy, as staged or simultaneousprocedures, in order to unload an arthritic com-partment and restore stability of the knee.10

The main indication for HTO is the correction ofvarus malalignment in medial unicompartmentalosteoarthritis of the knee. The aim is to unload themedial compartment by slightly overcorrectinginto valgus, in order to reduce pain, slow thedegenerative process and delay joint replace-ment.

The place of osteotomy in the management ofosteoarthritis of the knee has been formulated byISAKOS recently and ideal patients, possiblepatients and patients not suited for surgery havebeen defined (Table 1).

In the initial assessment weight-bearing antero-posterior (AP) and lateral radiographs and axial

Fig.1: Tibial Bone Varus Angle (TBVA):

Angle between the mechanical axis

(Line perpendicular to tibial plateau) and

epiphyseal axis (Line perpendicular to

the epiphyseal scar).

Table 1: Ideal and possible patients for high tibial osteotomy and patients not suited for the procedure according

to the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine

Ideal Possible Not suitedIsolated medial joint line pain Flexion contracture < 15° Bi-compartmental

(medial and lateral) OA***

Age (years) 40 to 60 Previous infection Fixed flexion contracture > 25°BMI* < 30 Age 60 to 70 or < 40 Obese patients

High-demand activity but no running or ACL, PCL or PLC** Menisectomy in the compartment to bejumping Insufficiency loaded by the osteotomy

Malalignment < 15° Moderate patellofemoralarthritis

Metaphyseal varus, i.e. TBVA > 5° Wish to continue all sportsFull range of movementNormal lateral and patellofemoral componentsIKDC (A) B,C,D. Ahlback I to IV80

No cupulaNormal ligament balanceNon-smokerSome level of pain tolerance

*BMI: Body mass index, TBVA: Tibial bone varus angle; IKDC: International Knee Documentation Committee osteoarthritisclassification**ACL: Anterior cruciate ligament; PCL: Posterior cruciate ligament; PLC: Posterolateral corner.***OA: Osteoarthritis

“Patient selection is

critical to the success

of knee osteotomy,

which may be

considered for patients

with a high-demand,

active lifestyle whose

life expectancy

exceeds the expected

survival of a knee

prosthesis”


views of the patellofemoral joint are taken as wellas whole-leg standing radiographs in order toassess alignment. Abnormal ligamentous laxity isnoted on clinical examination and on optionalstress radiographs. The presence of a constitu-tional varus morphotype and previous meniscalprocedures is documented. Tibial Bone VarusAngle (TBVA) (Fig. 1) which is the angle betweenthe mechanical axis of the tibia and the epiphysealaxis of the proximal tibia is an important prognosticfactor in patients of osteoarthritis with varusmalalignment.11 In patients with TBVA more than5 degrees, the long-term results of HTO have beenreported to be superior as compared to patientswith a TBVA of less than 5 degrees where the roleof HTO may only be palliative.11,12 Bonnin andChambat concluded that if patients are selectedfor osteotomy based on the TBVA, a successfulresult can be obtained in > 90% at ten years’ follow-up.11

HOW MUCH CORRECTION?

Correction of deformity is critical to the success ofa knee osteotomy. The normal mechanical axis ofthe limb, defined as a line from the center of the hipjoint to the center of the ankle joint, should passthrough or just medial to the center of the kneejoint. Angular deformity of the limb can be meas-ured as the angle subtended at the knee by a line

through the center of the femoral head and thecentre of the knee, and extended to the floor, anda line from the centre of the knee to the centre ofthe ankle. An angle of 0° to 3° of varus is consid-ered normal. The angle of correction of an oste-otomy is determined by adding to the deformity ofthe limb an overcorrection of 2° to 4° to ensure ashift of the weight-bearing force to the uninvolvedcompartment.13 Too little correction leads to poorresults and a recurrence of the varus malalignment;too much leads to a valgus overload andosteoarthritis of the lateral compartment.14,15

The position of mechanical axis in relation to thewidth of the tibial plateau is a better guideline toassess the pre and post-operative correction thanthe angle between mechanical and anatomicalaxis. Most recent researchers have approved ofthe work of Fujisawa et al,14 who concluded that,for optimal results, the corrected axis should runthrough the lateral 30% to 40% of the tibial plateau.Based on this clinical work, it is recommended bymany that the post-operative mechanical axisshould run laterally through the tibial plateau, at62% of its entire width, measured from the medialside.16-17

HTO also affects the slope of tibial plateau andthat may have a bearing on translational force ontibia in sagittal plane (Fig 2).

There is an evidence that closing-wedge oste-otomy leads to a decrease in tibial slope while anopen-wedge osteotomy leads to increase in thetibial slop.18 Agneskirchner et al.19 found thatchanges in tibial slope have a strong effect on thekinematics of the knee. They have shown threemain effects of changes in slope after high tibialosteotomy. The first is, either anterior or posteriortibial translation. There is a linear relationshipbetween tibial slope and tibial translation duringunilateral weight-bearing: the greater the angle ofslope the greater the anterior translation in ACL-intact and ACL-deficient knees. Consequently,the lower the angle, the lower the anterior transla-tion of the tibia. The second effect is a change indistribution of the mechanical load on the articularsurface. The increased slope after open-wedgehigh tibial osteotomy results in anterior transla-tion of the tibial plateau, leading to an anterior shiftof the tibiofemoral contact area with decompres-sion of the posterior femoral condyle, whereas areduction of the tibial slope in closed-wedge hightibial osteotomy results in exaggerated loading

Fig. 2: Change in the tibial slope after

HTO. Note the normal posterior slope is

reduced after closing wedge osteotomy.

“The main indication

for HTO is the

correction of varus

malalignment

in medial

unicompartmental

osteoarthritis of the

knee. The aim is to

unload the medial

compartment by

slightly overcorrecting

into valgus, in order to

reduce pain, slow the

degenerative process

and delay joint

replacement”

“It is recommended by

many that the post-

operative mechanical

axis should run

laterally through the

tibial plateau, at 62%

of its entire width,

measured from the

medial side”


posteriorly. The third effect is on extension of theknee, which is reduced after open-wedge andincreased after closed-wedge high tibial oste-otomy. This effect should be consideredpreoperatively in patients with limited extension.Change in the tibial slope following HTO has alsoa bearing when these patients require total kneearthroplasty and this aspect has been discussedlater.

VARIOUS TECHNIQUES OF HTO

There have numerous technique and fixation op-tions described in literature for high tibial oste-otomy including lateral closing wedge, medialopening wedge, V-osteotomy, dome osteotomyand biplanar osteotomy amongst others. Mosttechniques of HTO are lateral-based closing-wedge procedures. All require either a fibularosteotomy or a release of the proximal tibiofibularjoint, require osteosynthesis on the lateral side ofthe tibia and cause shortening. Large correctionsmay cause marked shortening of the leg and a largeoffset of the proximal tibia, which may compromiselater placement of the tibial component of a TKR.Two saw cuts are needed, and only mal-alignmentin the frontal plane can be corrected. The exposurerequired on the lateral side includes release of theextensor musculature and risks damage to thecommon peroneal nerve. This is said to occur inbetween 3.3% and 11.9% of patients, and indeedelectromyography shows damage in up to 27% ofpatients.20

Medial opening-wedge techniques of HTO, avoidmuscle detachment, dissection of the peronealnerve, shortening of the leg and fibular osteotomy.Only one saw cut is required, and corrections inthe frontal plane can be combined with adjust-ments in the sagittal plane. However, these proce-dures have been less popular, mainly becauseimplants for internal fixation have, until recently,been unable to withstand the axial and torsionforces in the proximal tibia. Another cause offailure is that if the osteotomy cut is made abovethe tibial tuberosity, little room is left for proximalfixation. A modification of the opening-wedgetechnique has been proposed in the form of abiplanar osteotomy in which a transverse cut iscombined with a second ascending cut behind thetuberosity.21 With this technique more room is leftfor proximal fixation and a buttress is createdwhich provides stability in the sagittal and trans-verse planes.

Various methods of fixation have been used byvarious researchers to fix the osteotomy thatinclude POP cast, staples, K-wires, Puddu Plates,buttress plates and LCP amongst others. Basedon the principle that bone healing is induced bythe micromovement which occurs across asplinted zone, a variety of plates have beendeveloped over the last 20 years, including lock-ing compression plates (LCP), the point contactfixation system (PC-fix) and the less invasivestabilisation system (LISS). They all consist ofan angle-stable plate-screw interface of lockingbolts, which increase the stiffness of the con-struct and obviate the need for rigid compressionof the plate against bone. With the LCP a combi-nation screw hole was introduced which can beused both for conventional fixation with rigidcompression, and for splinting. Good clinicalresults using these plates have been reported intreating fractures. These principles have beenapplied to the fixation of osteotomies. Platefixators have been developed based on the LCPconcept for opening-and closing-wedge oste-otomies. For an opening-wedge osteotomy along, T-shaped fixator plate is available (Tomofix;Synthes GmbH; Solothurn, Switzerland).Agneskirchner et al.19 demonstrated that a rigidlong-plate fixator with locking bolts yielded thebest results under biomechanical studies.

The general principles of bone healing apply toclosing wedge osteotomies, which can be consid-ered as optimally controlled fractures treated ac-cording to the standard protocol of fracture treat-ment. With radiographs taken at distinct intervals,e.g. at six weeks, three, six and 12 months, progres-sion of bone healing can be monitored. Bonehealing in opening-wedge osteotomies differs,however, because of the distraction and the gapwhich is created. In HTO performed without fillingthe gap it has been found that on plain radiographshealing occurs from lateral to medial, starting at thelaterally-based hinge point. One year after opera-tion full consolidation can be found in approxi-mately 90% of patients on radiographs, MRI andCT scans.23 Many surgeons, however, prefer to fillthe gap with bone graft. This view is based onvarious arguments, such as a reduction in localblood loss, an increase in mechanical stability andan increase in bone healing.24-25 However, no pro-spective randomised trials have yet been pub-lished that compare the various filling materialswith no filling at all.

“Closing-wedge

osteotomy leads to a

decrease in tibial

slope while an open-

wedge osteotomy

leads to increase in

the tibial slop”

“Medial opening-

wedge techniques of

HTO, avoid muscle

detachment,

dissection of the

peroneal nerve,

shortening of the leg

and fibular osteotomy.

Only one saw cut is

required, and

corrections in the

frontal plane can be

combined with

adjustments in the

sagittal plane”


TKA AFTER FAILED HTO

Total knee arthroplasty after a failed proximal tibialclosing-wedge osteotomy can be more difficult toperform than a primary knee replacement becauseof a shift of the proximal tibial articular surface inrelation to the medullary canal, osseous insuffi-ciency of the lateral aspect of the proximal part ofthe tibia, and altered patellofemoral mechanicscaused by patella infera and contraction of thepatellar tendon. Certain technical factors shouldbe taken into consideration when planning a kneereplacement following a HTO. The optimal skinincision should be a midline longitudinal incision,regardless of the previous incision used. Withsoft-tissue scarring following a HTO the subpe-riosteal exposure of the tibia is often more difficult.Patella eversion may also be difficult particularlyin the presence of patella infera. A lateral retinacularrelease early in the procedure may facilitate expo-sure. In some cases with severe scarring andpatella tendon shortening, a quadriceps snip orquadriceps turndown may be necessary. The pre-dominant abnormality in the proximal tibia is theloss of lateral bone stock. This can often be dealtwith by a minimal lateral resection. Ligamentouslaxity may also be seen in these knees, particularlythose that are in significant valgus. Soft-tissuebalancing may require releases and/ or ligamentadvancement. If retained hardware cannot be re-moved without extensive operative dissection atthe time of the knee replacement then it may beadvisable for the hardware to be removed throughthe previous incision and the TKR performed afterthe wound has healed.

The clinical results of TKA after high tibial oste-otomy vary. Windsor et al.26 reported that theywere not as satisfactory as those after primaryTKA, with thirty-two of forty-five knees having agood or excellent result at a minimum of two years.Katz et al.27 compared the results of twenty-onetotal knee arthroplasties after high tibial oste-otomy with those of twenty-one primary total kneearthroplasties. Seventeen of the arthroplastiesdone after an osteotomy had a good or excellentresult, whereas all twenty-one of the primary totalknee arthroplasties had a good or excellent result.In contrast, Staheli et al.28 reported that thirty-oneof thirty-five patients treated with total knee ar-throplasty after an osteotomy of the proximal partof the tibia had a good or excellent result. Medinget al.29 evaluated the results of ninety-five con-secutive total knee replacements performed ineighty-two patients at an average of ten years and

four months after high tibial osteotomy. While thenumber of previous operative procedures and theseverity of preoperative flexion contracture wererelated to diminished postoperative motion, theprevious high tibial osteotomy had no adverseeffect on the eventual results of the posteriorcruciate ligament-retaining total knee arthroplastyperformed with cement fixation.

SUMMARY

High tibial osteotomy remains an important tool ina surgeon’s armamentarium in treatment ofosteoarthritis of knee in carefully selected groupof high-demand patients. Adequate angular cor-rection, stable fixation, appropriate post-opera-tive rehabilitation, patient motivation and realisticexpectations make the procedure rewarding andensure a good long-term survivorship.Unicondylar knee replacement, also a treatmentoption for isolated medial/lateral compartmentalosteoarthritis, should usually be reserved for pa-tients expected to lead a sedentary lifestyle. Me-dial opening wedge osteotomy fixed with LCP isgaining popularity as the technique of choice forHTO as it also a stable fixation, obviates the needfor bone grafting and allows accelerated post-operative rehabilitation programme. Lastly, totalknee replacement following failed HTO is a moretechnically demanding procedure and long-termresults have not been as good as for primary totalknee replacement.

REFERENCES1. Noyes FR, Barber SD, Simon R. High tibial

osteotomy and ligament reconstruction in varusangulated, anterior cruciate ligament-deficientknees: a two-to seven-year follow-up study. Am JSports Med 1993;21:2-12.

2. Cicuttini F, Wluka A, Hankin J, Wang Y. Longitu-dinal study of the relationship between kneeangle and tibiofemoral cartilage volume in sub-jects with knee osteoarthritis. Rheumatology (Ox-ford) 2004;43:321-4.

3. Cerejo R, Dunlop DD, Cahue S, et al. Theinfluence of alignment on risk of knee osteoarthritisprogression according to baseline stage ofdisease. Arthritis Rheum 2002;46:2632-6.

4. Rand JA, Neyret P. ISAKOS meeting on themanagement of osteoarthritis of the knee prior tototal knee arthroplasty. ISAKOS Congress, 2005.

5. Staubli AE, De Simon C, Babst R, Lobenhoffer P.TomoFix: a new LCP-concept for open wedgeosteotomy of the medial proximal tibia: earlyresults in 92 cases. Injury 2003;34(Suppl 2):55-62.

6. Sommer C, Gautier E, Muller M, Helfet DL,Wagner M. First clinical results of the LockingCompression Plate (LCP). Injury 2003;34(Suppl2):43-54.

7. Wagner M, Frenk A, Frigg R. New concepts forbone fracture treatment and the Locking Com-

“Total knee

arthroplasty after a

failed proximal tibial

closing-wedge

osteotomy can be

more difficult to

perform than a primary

knee replacement

because of a shift of

the proximal tibial

articular surface in

relation to the

medullary canal,

osseous insufficiency

of the lateral aspect of

the proximal part of

the tibia, and altered

patellofemoral

mechanics caused by

patella infera and

contraction of the

patellar tendon”

“Adequate angular

correction, stable

fixation, appropriate

post-operative

rehabilitation, patient

motivation and

realistic expectations

make the procedure

rewarding and ensure a

good long-term

survivorship”


pression Plate. Surg Technol Int 2004;12:271-7.8. Healy WL, Barber TC. The role of osteotomy in

the treatment of osteoarthritis of the knee. Am JKnee Surg 1990;3:97-109.

9. Grelsamer RP. Unicompartmental osteoarthrosisof the knee. J Bone Joint Surg Am. 1995;77:278-92.

10. Noyes FR, Barber SD, Simon R. High tibialosteotomy and ligament reconstruction in varusangulated, anterior cruciate ligament-deficientknees. A two-to seven-year follow-up study. Am JSports Med. 1993;21:2-12.

11. Bonnin M, Chambat P. Current status of valgusangle, tibial head closing wedge osteotomy inmedial gonarthrosis. Orthopade 2004;33:135-42 .

12. Jenny JY, Tavan A, Jenny G, Kehr P. Long-termsurvival rate of tibial osteotomies for valgusgonarthrosis. Rev Chir Orthop Reparatrice ApparMot 1998;84:350-7

13. Hutchison CR, Cho B, Wong N, Agnidis Z, GrossAE. Proximal valgus tibial osteotomy forosteoarthritis of the knee. Instr Course Lect.1999;48:131-4.

14. Fujisawa Y, Masuhara K, Shiomi S. The effect ofhigh tibial osteotomy on osteoarthritis of theknee: an arthroscopic study of 54 knee joints.Orthop Clin North Am 1979;10:585-608.

15. Hernigou P, Medevielle D, Debeyre J, GoutallierD. Proximal tibial osteotomy for osteoarthritis withvarus deformity: a ten to thirteen-year follow-upstudy. J Bone Joint Surg [Am] 1987;69-A:332-54.

16. Dugdale TW, Noyes FR, Styer D. Preoperativeplanning for high tibial osteotomy: the effect oflateral tibiofemoral separation and tibiofemorallength. Clin Orthop 1992;274:248-64.

17. Miniaci A, Ballmer FT, Ballmer PM, Jakob RP.Proximal tibial osteotomy: a new fixation device.Clin Orthop 1989;246:250-9.

18. El-Azab H, Halawa A, Anetzberger H, Imhoff AB,Hinteruimmer S. The effect of closed- and open-wedge high tibial osteotomy on tibial slope: aretrospective radiological review of 120 cases. JBone Joint Surg [Br] 2008;90-B:1193-7.

19. Agneskirchner JD, Hurschler C, Stukenborg-Colsman C, Imhoff AB, Lobenhoffer P. Effect ofhigh tibial flexion osteotomy on cartilage pressureand joint kinematics: a biomechanical study inhuman cadaveric knees. Arch Orthop TraumaSurg 2004;124:575-84.

20. Aydogdu S, Yercan H, Saylam C, Sur H. Peronealnerve dysfunction after high tibial osteotomy: ananatomical cadaver study. Acta Ortho Belg1996;62:156-60.

22. Lobenhoffer P, Agneskirchner JD. Improvementsin surgical technique of valgus high tibial oste-otomy. Knee Surg Sports Traumatol Arthrosc2003;11:132-8.

23. BrinkmanJM, Lobenhoffer P, Agneskirchner JD,Staubli AE, Wymenga AB, van Heerwaarden RJ.Osteotomies around the Knee: Patient Selection,Stability of Fixation and Bone Healing In HighTibial Osteotomies. Journal of Bone and JointSurgery - British Volume, Vol 90-B, Issue 12,1548-57.

24. Hernigou P, Ma W. Open wedge tibial osteotomywith acrylic bone cement as bone substitute.Knee 2001;8:103-10.

25. Koshino T, Murase T, Saito T. Medial opening-wedge high tibial osteotomy with use of poroushydroxyapatite to treat medial compartmentosteoarthritis of the knee. J Bone Joint Surg [Am]2003;85-A:78-85.

26. Windsor RE, Insall JN, Vince KG. Technicalconsiderations of total knee arthroplasty afterproximal tibial osteotomy. J Bone Joint Surg Am.1988; 70:547-55.

27. Katz MM, Hungerford DS, Krackow KA, LennoxDW. Results of total knee arthroplasty after failedproximal tibial osteotomy for osteoarthritis. J BoneJoint Surg Am. 1987;69:225-33.

28. Staheli JW, Cass JR, Morrey BF. Condylar totalknee arthroplasty after failed proximal tibial oste-otomy. J Bone Joint Surg Am. 1987;69:28-31.

29. Meding JB, Keating EM, Ritter MA, Faris PM. Totalknee arthroplasty after high tibial osteotomy. ClinOrthop. 2000;375:175-84.


INTRODUCTION

There has been a resurgence of interest inUnicompartmental knee arthroplasty (UKA) in therecent past. The advantages of UKA include thepreservation of normal knee kinematics, lowerperioperative morbidity, less blood loss, and ac-celerated patient rehabilitation and recovery.1 Fora selected subgroup of patients with isolatedadvanced degenerative arthritis involving prima-rily the medial or lateral compartment of the knee,UKA may be the best surgical treatment option. Inaddition, often there is greater patient satisfactionwith UKA because the knee feels more like anormal knee, possibly because of the preservationof both cruciate ligaments after UKA. In a com-parative study in patients who underwent TKA onone side and UKA on the contralateral side,Laurencin et al.1 demonstrated that more patientspreferred the UKA side because it felt like a normalknee and had better function. Moreover, in aprospective, randomised study of 102 kneestreated with either TKA or UKA, Newman et al2

showed that patients in the UKA group had less

Unicompartmental KneeArthroplasty

VIJAY KUMAR

Assistant Professor

RAJESH MALHOTRA

Professor


AIIMS, New Delhi

ABSTRACT

The unicompartmental knee arthroplasty has evolved significantly over the past threedecades. The advantages of unicompartmental knee arthroplasty are lower perioperativemorbidity and earlier recovery. A successful unicompartmental knee arthroplastyfunctions closer to a normal knee. Both fixed- and mobile-bearing implants haveexcellent clinical outcomes at >10 years, but with different modes of long-term failure.Proper execution of surgical technique remains critical to optimizing outcome.

UKA

Keywords: Unicompartmental kneearthroplasty, Fixed bearing, Mobile bearing,Oxford UKA

perioperative morbidity, regained knee motion morerapidly, and had a higher percentage of excellentoutcomes based on the Bristol knee score. Patil etal.3 studied the kinematics of stair climbing in adynamic cadaveric model and found that, withregard to tibial axial rotation and femoral rollback,UKA more closely resembles normal knee func-tion than does TKA.

Comparisons of the early outcomes of UKA tothose of osteotomy typically reveal faster recov-ery, more predictable pain relief, and fewer surgicalcomplications after UKA. Stukenborg-Colsman etal4 reported a randomised, prospective study of 62patients undergoing either UKA or HTO. Kaplan-Meier survival analysis 7 to 10 yearspostoperatively showed a survivorship of 77% forUKA and of 60% for HTO, with a higher rate ofintraoperative and postoperative complicationsin the HTO group.

PATHOGENESIS OF UNICOMPARTMENTAL

OSTEOARTHRITIS

Isolated medial compartment disease

The progressive loss of articular cartilage over themedial compartment leads to varus malalignmentof the limb, which then further overloads thearticular cartilage and causes additional loss ofarticular cartilage over time. When the ACL isintact, the area of maximal articular cartilage loss is

“There is greater

patient satisfaction

with UKA because the

knee feels more like a

normal knee, because

of the preservation of

both cruciate

ligaments after UKA”


the anteromedial portion of the tibia and therewould be preservation of full-thickness articularcartilage on the posteromedial portion of the tibia.On the femoral side, almost all of the articularcartilage loss is from the distal femur, with theposterior femoral cartilage relatively well preserved.In patients without an ACL, the knee kinematicsare altered substantially and the pattern of arthritisis markedly less predictable. In many, but not all,ACL-deficient patients, sufficient lateral compart-ment disease or patellofemoral compartment dis-ease will be present such that a UKA is notappropriate.

Isolated lateral compartment disease

Isolated advanced degenerative arthritis of thelateral compartment of the knee is less commonthan medial-sided disease. The patient with val-gus deformity and lateral compartment diseaseoften presents with concomitant anterior kneepain or patellofemoral radiographic findings thatmakes UKA less appealing. The more complexkinematics of the lateral compartment of the knee,which includes greater amounts of gliding androlling than the medial side makes the pattern ofdegenerative change less predictable than in pa-tients with isolated medial disease.18

INDICATIONS AND CONTRAINDICATIONS

Kozinn and Scott5 provided a framework of indica-tions and contraindications to identify surgicalcandidates for UKA. The indications are a diagno-sis of unicompartmental osteoarthritis or os-teonecrosis in either the medial or lateral compart-ment; age >60 years with a low demand for activity;weight <82 kg (181 lb); minimal pain at rest; rangeof motion (ROM) arc >90° with <5° flexion contrac-ture; and an angular deformity <15° that is pas-sively correctable to neutral.

The ideal candidate for UKA is able to clearlypinpoint the medial (or lateral) joint line as thesource of pain that prevents him or her fromcarrying out activities of daily living. Bert6 haslabelled this concept the “one-finger test.” Askedto locate his or her pain, the patient points to theinvolved compartment with one finger. This con-cept is in contradistinction to the patient whoperforms a knee grab when asked to localise his orher pain, indicating more global pain distribution.Those patients who have diffuse knee pain or whoclearly identify anterior knee pain as substantiallylimiting will be served better with TKA. Specificanterior knee pain symptoms when squatting or

standing from a seated position also would sug-gest TKA rather than UKA.

Specific contraindications to UKA are a diagnosisof inflammatory arthritis; patient age <60 years;high patient activity level; pain at rest which mayindicate an inflammatory component to the ar-thropathy); and patellofemoral pain or exposedbone in the patellofemoral joint or opposite com-partment. Asymptomatic chondromalacia in thepatellofemoral joint is not a contraindication. Va-rus or valgus deformity of >10 degrees is typicallyaccompanied by degenerative changes in the othercompartments of the knee that make UKA lesspredictable. Furthermore, varus/valgus deformityof >10 to 15 degrees often requires collateralligament release at the time of surgery, which is notadvisable during UKA.

Patellofemoral arthritis and UKA

Traditionally, the presence of patellofemoral ar-thritis with unicompartmental arthritis has beenconsidered a contraindication for UKA. However,Price et al7 proposed that evidence of degenera-tive change of the patellofemoral joint, eitherradiographically or by direct inspectionintraoperatively, may be ignored if the patientdoes not specifically have anterior knee pain.

ACL and UKA

The stability of the ACL must be assessedpreoperatively. A deficient ACL is a contraindica-tion to the use of a mobile-bearing UKA designbecause the risk of bearing dislocation is substan-tial. Increased failure rates have been demon-strated in mobile meniscal bearing prosthesesimplanted in functionally ACL-deficient kneesbecause of instability and a propensity for meniscalbearing dislocation.8

Some authors suggest that a deficient ACL in alow-demand patient who has not experienced giv-ing way episodes is not a contraindication to afixed-bearing UKA. When UKA is selected forthese low-demand ACL deficient patients, careshould be taken not to increase the posterior slopeof the tibial component. For active, high-demandpatients and for those who have experiencedsymptomatic giving way episodes, an isolatedUKA is contraindicated in the face of ACL defi-ciency.18

Using a robotic testing system, Suggs et al9 foundmarkedly greater anterior tibial translation in the

“A deficient ACL is

a contraindication

to the use of a

mobile-bearing UKA

design because the

risk of bearing

dislocation is

substantial”

“The ideal candidate

for UKA is able to

clearly pinpoint the

medial (or lateral) joint

line as the source of

pain that prevents him

or her from carrying

out activities of

daily living”


specimens with sectioned ACLs who had beenimplanted a medial fixed bearing UKA. The au-thors postulate that if the ACL is deficient in UKAsimplanted in vivo, then clinical instability mayensue, predisposing the lateral and patellofemoralcompartments to continued articular damage.Moreover, Argenson et al10 fluoroscopically stud-ied in vivo patients with medial fixed bearingUKAs. These authors demonstrated that patientswith apparent ACL-deficiency had posterior con-tact position between the femoral and tibial com-ponents in full extension, with subsequent para-doxical anterior femoral translation into flexion.The result may increase anterior sliding of thefemoral component, on the tibial polyethylene,possibly accelerating the risk of polyethylenewear.

However, Christensen11 reported equivalent re-sults in patients with a deficient ACL and thosewith an intact ACL and suggested that an intactACL is not a prerequisite for a well-functioning,durable UKA. Hernigou and Deschamps12 alsoreported favourable results in UKAs in ACL-deficient knees, provided that the tibial compo-nent had been implanted at a slope of <7º.

Lateral UKA is contraindicated in ACL-deficientknees as the lateral compartment has inherentlymore motion than does the medial compartmentand will be subjected to even greater translation inthe setting of ACL insufficiency. This can result inan increased propensity for sliding motion andabnormal contact positions, with a potentiallyhigher rate of failure.13

Radiographic Investigations

A full-length standing radiograph including thehip-knee-ankle on a 3-foot film is useful for evalu-ation of the mechanical axis and anatomic axis canand the presence or absence of extra-articularbone deformity On a standing anteroposterior(AP) view of the knee, the contralateral tibiofemoralcompartment is examined for evidence of joint

space narrowing or osteophyte formation. Stressviews of the knee in varus and valgus are also doneto confirm the integrity of the opposite compart-ment and determine if adequate correction of thevarus-valgus alignment can be obtained withoutcollateral ligament release. The lateral radiograph,are required for templating as well as assessing thepatellar osteophystes. Axial views of the patellaare used to grossly assess the patellofemoralarticulation.

In rare circumstances, MRI might be helpful indetermining the status of the contralateral com-partment or the ACL. MRI however is helpful inpatients with avascular necrosis for whom UKA iscontemplated. Patients with spontaneous os-teonecrosis typically have small areas of necroticbone confined to the subchondral region, andthese patients are often good candidates for UKA.Some patients with AVN secondary to steroid usehave large, geographic avascular bone lesionsthat could compromise the fixation of the femoralor tibial component after UKA. MRI can be helpfulin determining the depth and extent of that necroticchange. If it appears that after the predicted bonecuts, a substantial portion of the UKA implant willrest on necrotic bone, then TKA is a better choice.18

PRINCIPLES OF TECHNIQUE

General principles of implant design

First, implant design should permit stable, long-term fixation to host bone. Second, the sagittal andcoronal plane geometry between the femoral andtibial components should strike a balance be-tween optimising contact area and limiting con-straint. Limiting contact area can minimizepolyethylene contact stresses and wear;overconstraint can lead to accelerated loosen-ing.14,15 There are two types of UKA implants i.e.a fixed bearing tibial component or a tibial compo-nent with a mobile meniscal bearing.

Fixed-bearing tibial components can be either allpolyethylene or metal backed. The modularity of

Table 1: Advantages and disadvantages of unicompartmental knee arthroplasty

versus total knee arthroplasty

Advantages Disadvantages

� Preserves both cruciate ligaments � Strict patient selection

� Increased range of motion � Technically more demanding

� Preserves bone stock � Potential for disease progression

� More normal kinematics in unresurfaced compartments of knee

� More normal proprioception

“Implant design should

permit stable, long-

term fixation to host

bone. The sagittal and

coronal plane

geometry between the

femoral and tibial

components should

strike a balance

between optimising

contact area and

limiting constraint”


metal-backed components facilitates easier femo-ral component insertion during the cementingprocess and allows the possibility of isolatedpolyethylene exchange, when required. The dis-advantage of this design is that either a thinnerpolyethylene liner or a larger tibial cut is needed toaccommodate the metal backing. Many modernUKA systems allow for implantation of either allpolyethylene or metal-backed components; goodclinical results have been reported with both.16

An alternative implant design philosophy is atibial component with a mobile meniscal bearing.The most successful fixed-bearing designs incor-porate round-on-flat or slightly dished geometries,mobile-bearing UKA components such as theOxford (Biomet, Warsaw, IN) are fully congruent(i.e., constant radius) with an uncaptured straighttrack (Fig. 1). Other mobile-bearing designs, suchas the LCS (Low Contact Stress) component(DePuy, Warsaw, IN), capture the mobilepolyethylene-bearing in a dovetail radial track,theoretically reducing the risk of bearing disloca-tion. The purpose of both of these mobile-bearingdesigns is to optimise congruency of the femoraland tibial components throughout ROM, therebyminimising point tibial contact forces and stress atthe implant fixation interface.17

Limb alignment and component positioning

The appropriate postoperative limb alignmentshould remain slightly undercorrected after UKA.In a varus knee undergoing medial compartmentUKA, this means leaving the limb with a mechani-cal axis that passes through the medial compart-ment just medial to the tibial spines. For mostpatients the postoperative anatomic femorotibialaxis would thus measure 2 to 4 degrees of valgusas opposed to the normal 6 degrees of valgus. Therationale for slightly undercorrecting the mechani-cal axis is to avoid overloading the articular carti-lage in the opposite compartment. Markedlyundercorrecting the knee is also inappropriate asit would then place excessive load on the UKAbearing and lead to failure owing to polyethylenewear.18

The tibial component should be implanted per-pendicular to the long axis of the tibia in thecoronal plane to facilitate implant congruencethroughout the flexion/extension arc. In a three-dimensional finite element analysis of tibial com-ponent inclination in UKA, Sawatari et al19 dem-onstrated increased cancellous bone stresses

when the tibial component was placed in varus.With regard to the sagittal plane placement of thetibial component, Hernigou and Deschamps12 rec-ommend ensuring a tibial slope of <7º to protectthe ACL from degeneration and rupture, mitigat-ing against late anteroposterior instability of theknee.

The degree of posterior slope is most often 5degrees but can vary based on patient and implantselection factors. For patients with ACL-deficientknees, less slope may be preferable. When animplant is used that has substantial sagittal planeconformity, then matching the posterior slope tothe patient’s anatomy is appropriate. The tibialcomponent must not overhang medially where itcan irritate the medial collateral ligament.

The femoral component should be placed perpen-dicular to the tibial component in the coronalplane. The femoral component must not extendanteriorly beyond the edge of subchondral boneor it can impinge against the patella. In the medial-lateral direction, the femur should be centeredover the tibial component without impingementinto the notch and without overhang medially. Thefemoral component should be rotated at 90 de-grees of flexion such that the femur and tibia areparallel, thus ensuring that edge loading of thefemoral component will not occur.

In both full extension and at 90 degrees of flexion,the femoral and tibial components should be par-allel such that edge loading of the polyethylenedoes not occur. The knee should be balanced toincorporate 2 mm of laxity in both flexion andextension.

Surgical techniques

The techniques used to implant contemporaryUKA designs include noninstrumented, free-handpreparation through intramedullary, extramedul-

Fig. 1: Mobile bearing Oxford

unicondylar knee arthroplasty implant

“The appropriate

postoperative limb

alignment should

remain slightly

undercorrected

after UKA”

“The rationale

for slightly

undercorrecting the

mechanical axis is to

avoid overloading the

articular cartilage in

the opposite

compartment”


lary, and computer-assisted instrumentation sys-tems.

Contemporary UKA is often done through a so-called minimally invasive surgical approach (MIS)which involves an 8- to 12-cm skin incision and ashort medial arthrotomy that stops at the superiorpole of the patella. A short split into the vastusmedialis muscle can be made (mini midvastusapproach) or alternatively the subvastus intervalcan be exploited if more exposure is needed. Thepatella does not need to be dislocated for UKA,and leaving the patella reduced in the trochleahelps the surgeon avoid some component orien-tation errors. If UKA is done using a traditionalTKA approach with the patella everted and theknee flexed, the tibia tends to externally rotate andthe medial flexion space tends to gap open, andthat can lead to component orientation problems.

A portion of the retropatellar fat pad and theanterior horn of the medial meniscus can be ex-cised for visualisation early in the case. Inmidflexion the status of the ACL, the lateral com-partment, and the patellofemoral joint are noted.Any intercondylar osteophytes can be removedfrom the notch to prevent impingement on theACL, and patellar osteophytes can be debrided.The sequence of bone cuts is determined by theparticular instrumentation system chosen by thesurgeon. Typically, on the tibial side the emphasisis on minimal bone resection with at most 2 mm ofbone removed from the most worn portion of thetibia. This cut is generally made perpendicular tothe long axis of the tibia.

Most tibial instrumentation systems use a verticalfree-hand cut from anterior to posterior, and thisshould be done as close to the medial tibial spineas possible without damaging the ACL. The sur-geon should reference the tibial tubercle to avoidthe tendency to internally rotate that sagittal planecut. Typically, the largest tibial component thatdoes not overhang should be selected. On thefemoral side, most instrumentation systems resectthe same thickness of bone (both distally andposteriorly) that will be replaced by the femoralimplant. If an intramedullary cutting guide is used,the knee is brought to midflexion to facilitateaccess to the intramedullary canal. Care is taken toprotect the patellar ligament and skin during thispart of the procedure. The femoral component issized from anterior to posterior such that 1 mm ofsubchondral bone is left exposed at the anterioredge of the component. That sizing will eliminateimpingement of the femoral component with thepatella even if the patient goes on to developpatellofemoral arthritis years later.

With a trial insert in place, the knee should bebalanced with symmetric flexion and extensiongaps of 2 mm. The overall mechanical alignment ofthe leg should be assessed with a cautery cord orlong drop rod. If questions exist about componentposition or limb alignment, an intraoperative x-rayfilm or fluoroscopy can be used.

COMPLICATIONS

Complications after UKA include infection, bleed-ing, nerve injury, prosthetic loosening, wear, con-tinued pain, thromboembolic disease, and bearing

Fig. 2: Mobile bearing oxford unicondylar knee arthroplasty

2a. Preop 2b. Postop

“The largest tibial

component that does

not overhang should be

selected”


dislocation. Prosthetic loosening, wear, or failurethat requires revision surgery can be estimated tooccur at a rate of 1% to 1.5% per year over the firstdecade. Slightly higher rates of failure have beenobserved in patients younger than 65 years of agecompared with those older than 65 years accord-ing to the Swedish Joint Registry data and from thegroup in Oxford, England. Late onset of pain canoccur from progression of disease in theunresurfaced compartments of the knee, implantloosening, or from polyethylene wear with asso-ciated synovitis. Between 10 and 15 years afterUKA, symptomatic patellofemoral arthritis hasbeen reported 10% of UKA patients in some series.For mobile-bearing designs, dislocation of thetibial bearing can occur, and the reported preva-lence is 0.5% to 1.5%. Patients with a deficient ACLare at particular risk for bearing dislocation aftermobile-bearing UKA. Fracture of the medial tibialplateau has been reported after UKA and is asso-ciated with the use of multiple pins to fix tibialcutting jigs to the proximal medial tibia. Similarfractures can occur after excessively deep tibialresections as well.

The important causes of long-term failure of UKAsinclude wear, loosening, and adjacent compart-ment degeneration.20,21 Gioe et al20 found an over-all survivorship of several different fixed-bearingdesigns of 88.6% at 10 years. Mean time to revisionsurgery was 3.62 years (range, 5 months to 8.4years). Progression of arthritis in uninvolved com-partments was the most common cause for revi-sion (51%), followed by aseptic loosening,polyethylene wear or osteolysis, and unexplainedpain. In contradistinction, an outcome analysis of1,135 revised UKAs from the Swedish registryindicated that the primary reason for revision wascomponent loosening (43% of cases), followed byprogression of adjacent compartment arthrosis(26%) and other mechanical problems (15%).21

Patellofemoral and opposite compartment

degeneration

The patellofemoral joint may be subject to pro-gressive deterioration after either medial or lateralUKA. The two distinct entities responsible forpatellofemoral symptoms that affect clinical out-come are progressive osteoarthritis and compo-nent impingement on the patella.12 Incongruity onthe preoperative axial skyline radiograph is animportant predictor of the joint-space narrowingseen at final follow-up. Femoral component im-pingement on the patella is associated more fre-

quently with lateral UKA and anterior placementof the femoral component. It is important to avoidcomponent oversising and place the femoral com-ponent in congruity with the anterior femur in thesagittal plane to prevent patellar impingement.22

Intraoperatively, one can mark the sulcus termina-lis, or the leading edge of the weight-bearingportion of the femoral condyle, as a reference pointfor sizing the femoral component. It is importantnot to size or implant the component beyond thislandmark.

The overcorrection of joint alignment transfersincreased weight-bearing force to the oppositetibiofemoral compartment, thereby acceleratingdegeneration.23 To prevent overcorrection, theauthors Berger et al.22 recommend not performinga formal medial collateral ligament release andinserting a polyethylene insert that allows 2mm ofjoint laxity in full extension and flexion.

Component wear and loosening

The cause of wear in UKA is multifactorial. At themanufacturing level, wear has been correlatedwith the shelf age of the polyethylene tibial com-ponent sterilised by gamma irradiation in air. Col-lier et al24 found that, with revision as an end point,the 6-year survival in a series of 100 UKAs was96% when the shelf age of the insert was <1.7 yearsbut only 71% when the shelf age was >1.7 years.A comparative study by Emerson et al25 demon-strated that the long term primary mode of failurediffers between fixed and mobile bearing UKAsdepending on surgical technique. In 51 fixed-bearing UKAs, the primary reason for revisionwas tibial component failure (e.g., polyethylenewear, aseptic loosening, subsidence of the tibialcomponent). However, because of concern formobile-bearing instability, the 50 mobile-bearingimplants were implanted with a tendency to stuffthe involved compartment, with a resultantovercorrection of deformity. The primary reasonfor failure of the mobile-bearing design was pro-gressive arthritis of the lateral compartment. Priceet al7 further confirmed this observation in a seriesof 439 medial Oxford UKAs, in which the primarycause for revision was progression of arthritis inthe lateral compartment.

CLINICAL RESULTS: FIXED VERSUS MOBILE

BEARING

Several published studies indicate the potentiallong-term success of both fixed- and meniscal-bearing UKA implants. Berger et al22 recently

“The important causes

of long-term failure of

UKAs include wear,

loosening, and

adjacent compartment

degeneration”

“It is important to

avoid component

oversising and place

the femoral component

in congruity with the

anterior femur in the

sagittal plane to

prevent patellar

impingement”


reported results of a modular fixed-bearing, metal-backed tibial component. These authors reportedan overall survival of the implant of 96% at aminimum 10-year follow-up (average, 12 years). Atfinal follow-up, 92% of patients had an excellent orgood outcome. Similarly, excellent long-term re-sults have recently been published on the Oxfordmeniscal-bearing UKA. Price et al7 reported a 15-year survival of 93% in 439 knees, with 91% goodor excellent clinical results. Several studies di-rectly compare the clinical results of mobile- andfixed-bearing UKAs. In a retrospective review,Emerson et al25 noted a survivorship, based oncomponent loosening and revision, of 99% for theOxford meniscal-bearing design and of 93% for theRobert Brigham fixed-bearing design (Johnson &Johnson Orthopaedics, Raynham, MA). A pro-spective, randomised controlled study comparingmeniscal bearing and fixed-bearing UKAs wasdone by Confalonieri et al,26 in which the authorscompared the AMC mobile-bearing component(Alphanorm, Quiershied, Germany) with the Alle-gretto fixed-bearing component (Centerpulse, Baar,Switzerland). At a mean 5.7-year follow-up, therewas no statistically significant difference betweenthe groups in terms of clinical outcome scores orrevision rates. Lewold et al.21 compared the 699mobile-bearing Oxford UKAs of the patients in theSwedish registry data set with a matched cohort offixedbearing Marmor UKAs. The 6-year revisionrate of the Oxford group was more than twice thatof the Marmor group. The most common cause ofrevision in the mobile-bearing group was disloca-tion of the polyethylene, a complication unique tothis group, especially early in the learning curve.Overall comparative data between fixed- and mo-bile-bearing components remain mixed.17

Conversion of UKA to TKA

Levine et al27 reported that, in 31 failed UKAsrevised to TKA, clinical results were comparableto those of primary TKA at follow-up of similarlength. In most cases, the posterior cruciate liga-ment could be spared and bone defects correctedwith simple wedges or cancellous grafts. McAuleyet al28 similarly noted in a series of 39 consecutiveUKA revisions that all tibial bone defects weremanaged effectively with local autograft or wedgeaugmentation; no patient required allograft boneor structural grafting. Femoral bone grafting alsowas not required in any patient. With modernimplants and close vigilance in monitoring forprogressive wear and bone loss, UKA may notsignificantly impair the results of future revision.

Barrett and Scott29 suggested that if minimal boneis rejected at the initial procedure and implants areobserved closely for evidence of wear or lysis,primary TKA implants can be used at the time ofrevision with successful outcomes. If bone aug-mentation, intramedullary implant stems, or con-strained implants are required, the results deterio-rate.29

CONCLUSION

Unicompartmental knee Arthroplasty continuesto evolve, with satisfying clinical results beenreported over three decades. There are issues withthe intricacies of the surgical technique, fixationmethods, and optimal implant design. Adherenceto strict surgical indications and appropriate pa-tient selection, combined with meticulous surgicalexecution, are important factors in optimising out-come.

REFERENCES1. Laurencin CT, Zelicof SB, Scott RD,Ewald FC:

Unicompartmental versus total knee arthroplastyin the same patient: A comparative study. ClinOrthop Relat Res 1991;273:151-56.

2. Newman JH, Ackroyd CE, Shah NA.Unicompartmental or total knee replacement?Five-year results of a prospective, randomisedtrial of 102 osteoarthritic knees withunicompartmental arthritis. J Bone Joint Surg Br1998;80:862-65.

3. Patil S, Colwell CW Jr, Ezzet KA, D’Lima DD: Cannormal knee kinematics be restored withunicompartmental knee replacement? J BoneJoint Surg Am 2005;87:332-38.

4. Stukenborg-Colsman C, Wirth CJ, Lazovic D,Wefer A: High tibial osteotomy versusunicompartmental joint replacement inunicompartmental knee joint osteoarthritis: 7-10-year follow-up prospective randomised study.Knee 2001;8:187-94.

5. Kozinn SC, ScottR. Unicondylar knee arthroplasty.J Bone Joint Surg Am 1989;71:145-50.

6. Bert JM. Unicompartmental knee replacement.Orthop Clin North Am 2005;36:513-22.

7. Price AJ, Waite JC, Svard U. Longtermclinicalresults of the medial Oxford unicompartmentalknee arthroplasty. Clin Orthop Relat Res 2005;435:171-80.

8. Goodfellow JW, Kenshaw CJ, Benson MK,O’Connor JJ. The Oxford knee forunicompartmental osteoarthritis: The first 103cases. J Bone Joint Surg Br 1988;70:692-701.

9. Suggs JF, Li G, Park SE, Steffenmeier S, RubashHE, Freiberg AA: Function of the anterior cruciateligament after unicompartmental knee arthro-plasty: An in vitro robotic study. J Arthroplasty2004;19:224-29.

10. Argenson JN, Komistek RD, Aubaniac JM, DennisDA, Northcut EJ, Anderson DT, Agostini S. In vivodetermination of knee kinematics for subjectsimplanted with a unicompartmental arthroplasty. JArthroplasty 2002;17:1049-54.

11. Christensen NO. Unicompartmental prosthesis forgonarthrosis. A nineyear series of 575 knees from

“If minimal bone is

rejected at the initial

procedure and

implants are observed

closely for evidence of

wear or lysis, primary

TKA implants can be

used at the time of

revision with

successful outcomes”


a Swedish hospital. Clin Orthop Relat Res1991;273:165-69.

12. Hernigou P, Deschamps G: Posterior Slope of thetibial implant and the outcome of unicompartmentalknee arthroplasty. J Bone Joint Surg Am2004;86:506-11.

13. Engh GA, Ammeen D. Is an intact anteriorcruciate ligament needed in order to have a well-functioning unicondylar knee replacement? ClinOrthop Relat Res 2004;428:170-73.

14. Schai PA, Suh JT, Thornhill TS, Scott RD.Unicompartmental knee Arthroplasty in middle-aged patients: A 2- to 6-year follow-up evaluation.J Arthroplasty 1998;13:365-72.

15. Hodge WA, Chandler HP: Unicompartmental kneereplacement:Acomparison of constrained and un-constrained designs. J Bone Joint SurgAm1992;74:877-83.

16. Hyldahl HC, Regnér L, Carlsson L, Kärrholm J,Weidenhielm L. Does metal backing improvefixation of tibial component in unicondylar kneearthroplasty? Arandomizedradiostereometric analy-sis. J Arthroplasty 2001;16:174-79.

17. Todd Borus, ,Thomas Thornhill, :UnicompartmentalKnee Arthroplasty. Journal of the AmericanAcademy of Orthopaedic Surgeons 2008;16:9-18

18. Mark W Pagnano, Robert S. Rice:Unicompartmental Knee Arthroplasty. Adult Re-construction, 1st Edition, 2007;165-69.

19. Sawatari T, Tsumura H, Iesaka K, Furushiro YTorisu T. Threedimensional finite element analysisof unicompartmental knee arthroplasty: The influ-ence of tibial component inclination. J Orthop Res2005;23:549-54.

20. Gioe TJ, Killeen KK, Hoeffel DP, Bert JM, ComfortTK, Scheltema K, Mehle S, Grimm K: Analysis ofunicompartmental knee arthroplasty in a commu-nity-based implant registry. Clin Orthop Relat Res

2003;416:111-19.21. Lewold S, Robertsson O, Knutson K, Lidgren L:

Revision of unicompartmental knee arthroplasty:Outcome of 1,135 cases from the Swedish KneeArthroplasty study. Acta Orthop Scand1998;69:469-74.

22. Berger RA, Meneghini RM, Jacobs JJ,SheinkopMB, Dell Valle CJ, Rosenberg AG, Galante JO:Results of unicompartmental knee arthroplasty ata minimum of 10 years follow-up. J Bone JointSurg Am 2005;87:999-2006.

23. Squire MW, Callaghan JJ, Goetz DD, Sullivan PM,Johnston RC. Unicompartmental kneeplacement:Aminimum 15 year followup study. ClinOrthop Relat Res 1999;367:61-72.

24. Collier MB, Engh CA Jr, Engh GA. Shelf age ofthe polyethelene tibial component and outcomeof unicondylar knee arthroplasty. J Bone JointSurg Am 2004;86:763-69.

25. Emerson RH Jr, Hansborough T, Reitman RD,Rosenfeldt W, Higgins LL. Comparison of a mobilewith a fixedbearing unicompartmental knee im-plant. Clin Orthop Relat Res 2002;404:62-70.

26. Confalonieri N, Manzotti A, Pullen C. Comparisonof a mobile with a fixed bearing unicompartmentalknee prosthesis: A prospective randomized trialusing a dedicated outcome score. Knee2004;11:357-62.

27. Levine WN, Ozuna RM, Scott RD, Thornhill TS.Conversion of failed modern unicompartmentalArthroplasty to total knee arthroplasty. J Arthro-plasty 1996;11:797-801.

28. McAuley JP, Engh GA, Ammeen DJ. Revision offailed unicompartmental knee arthroplasty. ClinOrthop Relat Res 2001;392:279-82.

29. Barrett WP, Scott RD: Revision of failed unicondylarunicompartmental knee arthroplasty. J Bone JointSurg Am 1987;69:1328-35.


INTRODUCTION

Virtual reality (VR) is a technology which allows auser to interact with a computer-simulated envi-ronment. Most virtual reality environments areprimarily visual experiences, displayed either on acomputer screen or through special stereoscopicdisplays, but some simulations include additionalsensory information, such as touch, sound andsmell .1

In the past few years augmented reality systemshave moved from research laboratories intoeveryday use for assisting in medical proce-dures. Systems are being used for training,preoperative planning, preoperative and intra-operative data visualisation, and intra-opera-tive tool guidance.2 Augmented reality also re-ferred to as enhanced reality or hybrid reality isa display technique that offers guidance andassistance in the navigation and understandingof a real world environment by combining sup-plemental information with a view of the realworld. The supplemental information typicallyis composed of computer generated imagery(three-dimensional renderings of anatomic fea-tures or contour outlines of anatomy, for exam-ple), but can be as simple as arrows and texthighlighting a feature in the environment.1,3

The medical domain uses imagery from manydifferent sources including x-ray, fluoroscope,ultrasound, computed tomography (CT), and mag-netic resonance (MR) imaging. Traditional meth-ods used by surgeons to view these images in-clude two-dimensional films on light tables andgraphics on a computer monitor.4 A major draw-back with the traditional approaches is the lack ofa direct spatial relationship between the patientand these images. When images are used to locateanatomic structures during surgery, the surgeonmust view the structure in the two-dimensionalimages and then correlate the structure to thepatient. This often requires the surgeon to recon-struct and transform the images mentally into thesame orientation and position as the patient.

HISTORY

The virtual environment was first tried in 1920 withmechanical flight simulators (Fig. 1). In 1956, MortonHidlig made Sensorama, a motorcycle simulatorwith visual, sound, vibration and smell simulationbut was not a commercial success.1

The Medical use of virtual reality was realised in1980s when different experiments were conducted.From head mounted devices in 1980s to virtualretinal displays in late 1990s to the present day

The Uses and Benefits ofVirtual Reality in Medicine

VIRTUAL REALITY

IN MEDICINE

R RAMBANI

SpR Trauma and Orthopaedics

Leeds Teaching HospitalNHS Trust, Leeds, UK

ABSTRACT

Computer modelling and simulation have become increasingly important in manyscientific and technological disciplines owing to the wealth of computational power.The increasing use of computers in medicine has lead to better training opportunitiesfor all the training professionals. The ultimate goal is to allow the presentation of virtualobjects to all of the human senses in a way identical to their natural counterpart. Thiswill allow lesser risk to the patients and better training environment to simulate the realscenarios and virtual patients for budding doctors and surgeons.

“Virtual reality (VR) is

a technology which

allows a user to

interact with a

computer-simulated

environment”


experimentation on robotics surgery in medicine.The virtual reality system has evolved over aperiod of time to be used as an important surgicaltool.5

The enormous potential of virtual environment inorthopaedics for training was realised and differ-ent centres started developing tools for orthopae-dic training. Augmented reality also can be com-bined with arthroscopy to provide the surgeon amore global view of the joint, presenting the scopeimage and orientation in an easier to comprehendcontext. This can give the surgeon greater controlin the manipulation of soft tissues such as liga-ments. The arthroscopic system can be enhancedby instrumenting the tooling with strain gauges orsimilar sensors. The magnitudes and directions ofthe tooling forces can be displayed by the aug-mented reality system, allowing the surgeon toapply more directed force without damaging theanatomy. The first among few were the VirtualEnvironment Knee Arthroscopy Training System(VE-KATS) which was developed to train ortho-paedic trainees in knee arthroscopy.3

Initial research over the past 5-10 years in videotechnology, graphics, computer-aided design(CAD) and virtual reality has given an insight intosome of the requirements for a virtual-reality sur-gical simulator.6 Using CT or MRI scan images

would require substantially more computer power.The algorithms for object deformation and gravityare available and continue to evolve. Alternatedisplay technologies such as high-definition tel-evision (HDTV) and holography are still in theprototype stages and have not been explored fora virtual-reality environment. Finally, the humaninterface with a simulator must be as “natural” aspossible; sitting in front of a 2-D video screen witha keyboard would detract from even the mostrealistic images in a simulation.7

TYPES OF VIRTUAL REALITY SYSTEMS

Augment reality system is currently been used indifferent orthopaedic procedures as a mode oftraining and diagnosis of orthopaedic diseases.An augmented reality system consists of threebasic components: a display device, a positiontracking system, and software to correlate posi-tions and transform images. These three subsys-tems are tied together by a computer workstation.

Other system includes, Window on World Sys-tems, Video mapping (1st Person shooters), FishTank Virtual Reality (immersa desk), ImmersiveSystems, Telepresence, Mixed or AugmentedReality. These have been tested for use in differentorthopaedic procedures for teaching and surgicaltools.1

The virtual environment technologies and appli-cations that support this framework can be dis-cussed within the context of the provision ofmedical care, mainly for diagnosis, therapy andeducation and training. However, there is overlapin many of these areas, for education and trainingis increasingly being embedded into the actualdevices which are being used for diagnosis andtherapy.

BENEFITS AND USES

Virtual reality and augmented reality (VR-AR) arecapable of generating visual representations ofcomplex operations and procedures from sci-ence, education, and technology in virtual, three-dimensional rooms – thereby making the opera-tions more tangible and interpretable for theviewer.

In the past decade medical applications of virtualreality technology have been rapidly developing,and the technology has changed from a researchcuriosity to a commercially and clinically impor-tant area of medical informatics technology.

Fig. 1: Flight simulation model

“An augmented reality

system consists of

three basic

components: a display

device, a position

tracking system, and

software to correlate

positions and

transform images.

These three

subsystems are tied

together by a computer

workstation”


DIAGNOSTICS

Initially, algorithms for graphical rendering ofanatomy have been used to provide support forthree dimensional organ reconstructions from ra-diological cross sections. For the clinician thismethod of visualisation provided a more naturalview of a patient’s anatomy without losing the seethrough capability of the radiologist.

Virtual endoscopy techniques (such as virtualarthroscopy) based on the virtual reconstructionand visualisation of individual patient anatomyare rapidly developing. Owing to the potentialbenefits of patient comfort and cost effectivenessvirtual arthroscopic procedures could replace realarthroscopic investigations in the foreseeablefuture in some areas of diagnosis.4,8

PREOPERATIVE PLANNING

In many areas today the use of computer modelsto plan and optimise surgical interventionspreoperatively is part of daily clinical practice. Insome areas, such as complex pelvic and limbreconstruction surgery, treatment is not possiblewithout preoperative planning with the aid of acomputer. In other areas, such as craniofacialneurosurgery and open neurosurgery, the possi-bility of planning surgery on a computer screen,trying out different surgical approaches with real-istic prediction of the outcome (for example, post-operative appearance of the patient), and plan-ning individualised custom made implants havesubstantial impact on the success and safety ofthe intervention.9

EDUCATION AND TRAINING SYSTEMS

Education and training is one of the most promis-ing application areas for virtual reality technolo-gies. Computerised three dimensional atlases pre-senting different aspects of the anatomy,physiology, and pathology as a unified teachingatlas are about to revolutionise the teaching ofanatomy to medical students and the generalpublic.

Systems based on virtual reality offer a uniqueopportunity for the training of professional surgi-cal skills on a wide scale and in a repeatablemanner, in a way similar to the routine training ofpilots (Fig. 2, 3). Contrary to the preoperativeplanning systems, which require an extreme levelof accurate registration and alignment of tissue(data fusion), medical and surgical education andtraining rely more on high fidelity visualisationand realistic immersion into the virtual scene thanon the precise data fusion of the applied modelswith the specific anatomy of a patient.10

Virtual reality provides the first opportunity tocombine 3-D visual imagery with interactivity at alevel that would permit realistic simulation of com-plex anatomic dissection or performance of surgi-cal procedures. It can make learning surgicalanatomy easier by allowing the student to explorethe interrelations of various organ systems inperspectives not available through other stand-ard teaching techniques. Eventually it will bepossible to “dissect” a virtual cadaver, resulting ina very effective educational tool.10,11

Fig. 2: Haptic feedback model for training of fracture fixation

“Virtual endoscopy

techniques based on

the virtual

reconstruction and

visualisation of

individual patient

anatomy are rapidly

developing. Owing to

the potential benefits

of patient comfort and

cost effectiveness

virtual arthroscopic

procedures could

replace real

arthroscopic

investigations in the

foreseeable future in

some areas of

diagnosis”


The surgical simulator can be used in surgicalresidency training and research. A resident canpractice a surgical procedure repeatedly until per-fect before performing it on a patient. A researchercan attempt new surgical procedures repeatedlybefore the first attempts on an animal model.11

Teaching surgical skills becomes easier. Risks arefewer. Fewer animals are needed for research.

In the current conventional configuration (HMDand DataGlove), the simulator is a “stand-alone”teaching system. It is envisioned that in the future,the simulator (or the Virtual Limb) could be con-nected to a Green Telepresence Surgery System,which does not use a HMD and DataGlove. Thisis an ideal human interface, for the same surgicalworkstation which will be used to perform realoperative procedures through telepresence sur-gery could access a simulated virtual abdomenand practice surgical procedures on the computer-generated model.9,12 Also, a surgical simulatorcould be networked (like the military battle- train-ing simulator SIMNET), so multiple surgeonscould practice or do surgical research in the com-puter-generated virtual environment.11 These ad-vantages are appealing in this era of animal-rightssensitivity and of fear of exposure to blood-bornediseases such as AIDS and hepatitis.

The rapid adoption of minimally invasive surgicaltechniques is one of the major driving forces in thedevelopment of surgical trainers. The extreme

limitations placed on visual and manipulative free-dom, including the loss of tactile feedback and theunusual hand-eye coordination makes extensivespecialised training for such interventions neces-sary.13 Virtual reality is the technology of choicewith the greatest potential for future development,and a rapidly growing number of commercial unitsare becoming available.

IMAGE GUIDED SURGERY

Even the best preoperative planning is of limiteduse if its implementation in the operating room isnot guaranteed. Whereas traditionally theseplans are transformed mentally by the surgeonduring the intervention, computer assistanceand virtual reality technology can substantiallycontribute to the precise execution of preoperativeplans.

Image guided surgery is the typical applicationarea where virtual objects (data from thepreoperative image and the anatomical objectsextracted from them) and real objects (the patientand the surgical tools) must be merged into asingle unified scene, calling for augmented realitytechniques.9 The major technical issue to be solvedis the registration of the real and virtual objects–that is, to make the preoperative data coincide withthe actual patient anatomy–and the tracking of themovement of real objects such as the surgicalinstruments.

Fig. 3: Haptic feedback model for training of fracture fixation

“The surgical

simulator can be used

in surgical residency

training and research.

A resident can practice

a surgical procedure

repeatedly until

perfect before

performing it on a

patient”


Although still needing substantial research imageguided surgery is one of the major developmentareas today, with several systems in routine clini-cal practice, especially in orthopaedics and neuro-surgery.7

OTHER APPLICATION AREAS

Virtual reality offers promising solutions in manyother areas of medical care, where the immersioninto a virtual world can help the patient, the phy-sician, and the developer of the technology. Sev-eral systems have been developed and tested forphysical or mental rehabilitation and for support-ing mental health therapy by exposing the patientto appropriate experience or illusion. Finally, vir-tual reality based technology plays a major role intelemedicine, ranging from remote diagnosis tocomplex teleinterventions.5

CONCLUSION

Virtual reality technology aims at closing the gapbetween the capability of present technology toacquire images and properties and then to calcu-late the behaviour of virtual objects, and the abilityto observe and interact with them. The ultimategoal is to allow the presentation of virtual objectsto all of the human senses in a way identical to theirnatural counterpart. In some applications real andvirtual objects need to be integrated making itnecessary to present and manipulate them simul-taneously in a single scene, leading to the devel-opment of hybrid systems referred to as aug-mented reality systems.

REFERENCES1. Richard M. Satava, CDR Shaun B. Jones. Medical

Applications of Virtual Reality. Med Appl of VR-VR

Handbook, DARPA Publication: chapter 1999;55:1-

24.

2. Gallagher AG, Cates CU. Virtual reality training for

the operating room and cardiac catheterisation

laboratory. Lancet 2004;364(9444):1538-40.

3. Sherman KP, Ward JW, Wills DP, Sherman VJ,

Mohsen AM. Surgical trainee assessment using a

VE knee arthroscopy training system (VE-KATS):

experimental results. Stud Health Technol Inform

2001;81:465-70.

4. Eckhoff DG, Bach JM, Spitzer VM, Reinig KD,

Bagur MM, Baldini TH, et al. Three-dimensional

mechanics, kinematics, and morphology of the

knee viewed in virtual reality. J Bone Joint Surg

Am 2005;87(Suppl 2):71-80.

5. Wilson JR. Virtual environments applications and

applied ergonomics. Appl Ergon 1999;30(1):3-9.

6. Frey M, Riener R, Burgkart R, Proll T. Initial results

with the Munich knee simulator. Biomed Tech

(Berl) 2002;47(Suppl 1 Pt 2):704-7.

7. Benabid AL, Hoffmann D, Ashraf A, Koudsie A,

Esteve F, Le Bas JF. Robotics in neurosurgery:

current status and future prospects. Chirurgie

1998;123(1):25-31.

8. Robinson M, Eckhoff DG, Reinig KD, Bagur MM,

Bach JM. Variability of landmark identification in

total knee arthroplasty. Clin Orthop Relat Res

2006;442:57-62.

9. Voss G, Bisler A, Bockholt U, Muller-Wittig WK,

Schaffer A. ICAPS an integrative computer-

assisted planning system for pedicle screw inser-

tion. Stud Health Technol Inform 2001;81:561-3.

10. Heng PA, Cheng CY, Wong TT, Wu W, Xu Y, Xie

Y, et al. Virtual reality techniques. Application to

anatomic visualization and orthopaedics training.

Clin Orthop Relat Res 2006;442:5-12.

11. Tillander B, Ledin T, Nordqvist P, Skarman E,

Wahlstrom O. A virtual reality trauma simulator.

Med Teach 2004;26(2):189-91.

12. Kalawsky RS. VRUSE-a computerised diagnostic

tool: for usability evaluation of virtual/synthetic

environment systems. Appl Ergon 1999;30(1):11-

25.

13. Stanton D, Foreman N, Wilson PN. Uses of virtual

reality in clinical training: developing the spatial

skills of children with mobility impairments. Stud

Health Technol Inform 1998;58:219-32.

“Virtual reality offers

promising solutions in

many other areas of

medical care, where

the immersion into a

virtual world can help

the patient, the

physician, and the

developer of the

technology”


There are those who ardently advocate it, -there are those who in great part reject it,-and there are those who, Laodicean-like arelukewarm concerning it, and finally somewho, without convictions, are either for oragainst it, use it or dispense with it, as chanceor whim, not logic may determine.1

Joseph Price, 1888

Hippocrates’s “hollow pencils” to treat empymaare the earliest recorded use of drains in history.2

This was followed by use of conical metal tubes byAurelius Celsus and leaden tubes by ClaudiusGalen in management of ascitis. In modern era,

lucid descriptions of the use of drains were madeby Ambrose Pare (1510-1590), Lister, Neuber,Theodore Bilroth and many others2. Though theuse of drains was also common in orthopaedicsurgeries, it was popularised by Waugh andStinchfield. 3

TYPES OF DRAINAGEOpen systemWound secretion drained into the wound dress-ing via a rubber or latex drain e.g., penrose drainsMikulicz drain.

Mikulicz drain was developed by Johann VonMikulicz in 1886.4 They were widely used beforethe era of antibiotics for drainage in cases of intra-abdominal sepsis. The Mikulicz drain consists ofa circular laparotomy gauze 50-70 cm in diameter,according to the size of the wound cavity to be

Know your Equipment:Wound Drain

Keywords: Wound drain, Fluid aspiration,Surgical drainage

DHARMESH KHATRI

Senior Resident

VIJAY KUMAR

Assistant Professor

RAJESH MALHOTRA

Professor


AIIMS, New Delhi

ABSTRACT

The use of drains in orthopedic surgeries was popularised by Waugh and Stinchfield.Surgical drainage is indicated for therapeutic and prophylactic purposes. Thetherapeutic use of drains is better understood and less controversial than their useprophylactically. Usually drains with diameter of 14-16 charriere are used. The rate ofproduction of secretion is not affected by the size of the drain. Also, tube wall shouldbe sufficiently thick so that it does not collapse and become ineffective by suctionpressure. At the time of insertion, the complete system including the drain, connectingtubing and receptacle has to be assembled in the operating room maintaining thesterility of the equipment. The time of removal depends upon the daily production ofthe drainage. It also depends upon the indication of the drain. The VAC (vacuum-assisted closure) system is a non-invasive therapy based on the application ofnegative pressure by controlled suction to the wound surface. This method has beenproved to be effective in promoting granulation tissue proliferation. The vacuum-assisted therapy system is a valuable and effective tool in the management of patientswith difficult wound and several studies have reported promising results.

ORTHOPAEDIC EQUIPMENT

“Hippocrates’s

“hollow pencils” to

treat empyma are the

earliest recorded use

of drains in history”


treated. A 2-0 Nylon thread can be fixed to thebottom of the drainage sac, which serves to with-draw it when the drain is removed. The inside of thedrainage sac is packed with several layers of gauze(varying in number according to the size of thecavity), and a drainage tube can be inserted forfluid aspiration and irrigation.

Semi-open systemWound secretion flow into an attached drainagebag.

Closed systemThe drainage tube is tightly connected to the bagand a unidirectional valve prevents reflux of secre-tion.

METHOD OF DRAINAGEPassive systemHere capillary force or gravity is used to drainbody cavities. In a closed system this is done bygravity drainage or through a flow within thedrainage tubing in to water filled receptacle knownas underwater drainage. An example is Robinsondrainage system5 which consists of asilicone rubber tube drain 1 meter in length and20 charriere in diameter (though now it is availablein various lengths and diameters). It has amultiperforated end. Tube is attached to a 350 mlplastic bag with drain-off outlet which is hookedon to the bedside. (One charrière = 1/3 millimeter.Symbol, Fr. Thus a 3-charrière catheter would havea diameter of 1 millimeter). Silicone rubber tubewas used to overcome premature occlusion of thelumen or walking off of the area where in the tubeis placed.

Active systemDrainage is done with use of suction force byconnecting drain to a suction pump or externalvacuum system e.g. Redon drainage system, slitdrainage, Jackson-Pratt drainage.� Redon drainage system: Made from PVC. The

length of the drain is between 30 and 50 cm,and diameter between 6-18 charriere. At itsend which will be inserted into the wound aremultiple lateral perforations extending overthe distance of 8 to 15 cm. Different recepta-cles are available for collection of drainage,however the 400 ml capacity with a vacuum of-800 mbar is preferred. However, the holes ofRedon tubes may get blocked by invaginatedloose tissues or blood clots and the drain maybecome ineffective.

� Slit drainage: The end of the tubing is splitcrosswise resulting in four flexible,

15 cm long, quarter round tongues. It does nothave perforations. Slits prevent the frequentlyoccurring blocking of the tubing.

� Jackson-Pratt drainage: Made from Silastic.Vacuum is obtained by compressing manuallya 100 cm3 reservoir upto desired level.

ADVANTAGES OF DRAINAGE6

� Avoidance of haematoma.� Decrease of dead space and approximation of

tissue layers.� Prevention of infection.� Early detection of infection and early detec-

tion of complications such as postoperativehaemorrhage.

� Aspiration of pus and necrotic material.� Accelerated wound healing through vacuum

sealing in the presence of tissue voids.� Perioperative use of a cell saver possible.

DISADVANTAGES OF DRAINAGE7,8

� Potential conduit for the entry of bacteria.� Being a prosthetic material, it can compromise

the host defense mechanism and act as sup-port for developing infection.

� Suction drainage can increase postoperativeblood loss by decreasing the tamponade ef-fect.

� Premature blockage of the suction tubes.� Breakage of drain tube or drain getting caught

in deep sutures leading to reoperation.� Pain and discomfort at the time of removal of

drain.� Risk of formation of fistulae and joint effusion.

INDICATIONSSurgical drainage is indicated for therapeutic andprophylactic purposes. The therapeutic use ofdrains is better understood and less controversialthan their use prophylactically.Indications for therapeutic drainage:� Large haematomas or collection of fluids.� Collection of purulent material and necrotic

debris.� In vacuum sealing of wounds.� As suction-irrigation drainage in osteitis, joint

infection or osteomyelitis.

Indications for prophylactic drainage� Large separation of tissue layers- decollement.� Large dead space after surgery.� Defects in cancellous bone such as after har-

vesting cancellous bone grafts.� Bleeding coagulopathy.� After synovectomy and arthrolysis.

“The therapeutic use

of drains is better

understood and

less controversial

than their use

prophylactically”


However, prophylactic use of drain after electivesurgery in orthopaedics and traumatology is con-troversial. There are no randomised control trialsestablishing the routine prophylactic use of drain-age after surgery.

DIAMETER OF TUBINGSmall-bore drains have high chances of gettingclogged and hence large-bore drains should beused. Usually drains with diameter of 14-16 charriereare used. The rate of production of secretion is notaffected by the size of the drain. Also, tube wallshould be sufficiently thick so that it does notcollapse and become ineffective by suction pres-sure.

TECHNICAL CONSIDERATIONAll parts of the drainage system should be packedunder sterile conditions. At the time of insertion,the complete system including the drain, connect-ing tubing and receptacle has to be assembled inthe operating room maintaining the sterility of theequipment. Exit the drain from inside out over atrocar with pointed tip, 1-2 cm away from the skinincision. If several drains are to be used, then thedeeper inserted drain should lie further away fromthe skin incision, and more superficially inserteddrain should lie closer to the skin incision. Drainscan also be marked with a thread or an adhesivestrip for localization to a particular site. Avoidkinking of the drains and ensure that drain is notinadvertently tied while closing the wound. En-sure free mobility of the drain before dressing. Alldrains should be fixed preferably with apolyfilament thread. Do not obstruct the lumen ofthe tube while knotting the thread. Keep the recep-tacle below the level of the wound.

REMOVAL OF DRAINThe time of removal depends upon the daily pro-duction of the drainage. It also depends upon theindication of the drain. Drains inserted after sur-gery for prophylactic use should be removed after24 hours. Studies7 have shown thatpostoperatively 50 % of collection is drained withinfirst 2 hours and during the first 24 hours 85 % oftotal production is aspirated. There is no advan-tage to prolong the suction since this does notdecrease the incidence of haematoma formationand wound complications. Also there is increasedrisk of infection by prolonging the drainage espe-cially if the drain is intraarticular. For infections,the drain should be kept at least for 48- 72 hoursor till the time no more fluid is aspirated. The tip ofthe drain should be sent for microbiological exami-nation.

WOUND DRAINS AND INFECTIONDrains have been implicated in several clinicalstudies8,9 as a contributing factor to the develop-ment of infection. Various mechanisms that areproposed are:� Drains provide route by which bacteria can

gain access to the tissues.� Drains act as foreign bodies and damage tis-

sue defenses.

Magee et al10 in their experimental study on guineapigs found that the presence of drains in softtissue wounds in experimental animals damagedhost defenses. The bacterial counts of the drainedwounds were considerably greater than those ofundrained wounds. Bacteria can migrate from theskin around the drain into the depths of the wound.When sump drains are employed air-borne bacte-ria can be drawn into the wound through the airvents. Use of bacterial filter in the air vent canavoid this problem.

CLAMPING OF DRAINSThere are various studies that have shown thatclamping of drain for certain period postoperativelydecreases the blood loss without affecting thewound healing. Roy et al11 have shown in theirprospective randomised study in hundred pa-tients that delaying release of the drains by onehour reduces postoperative blood loss and trans-fusion requirement following total knee arthro-plasty. Brueggemann et al12 also showed in theirstudy that transfusion requirements are reducedif the drains are intermittently clamped after sur-gery.

VACUUM-ASSISTED CLOSUREThe VAC (vacuum-assisted closure) system is anon-invasive therapy based on the application ofnegative pressure by controlled suction to thewound surface. This method, first described byFleischmann et al13 in 1995 and then by Argentaand Morykwas14 in 1997, has been proved to beeffective in promoting granulation tissue prolif-eration. The negative pressure leads to arteriolardilatation and decreases fluid excess, which re-sults in improved microcirculation, enhanced epi-thelial proliferation and fibroblast migration lead-ing to granulation tissue proliferation.15 Vacuumcondition also reduces bacterial colonisation. Thevacuum device usually consists of a sponge thatis applied directly to the wound, connected to adrainage tube and covered by a transparent adhe-sive plastic film. The system is linked to a machinethat produces negative pressure at 50-125 mm/Hg,resulting in a decrease in the local interstitial

“If several drains are

to be used, then the

deeper inserted drain

should lie further away

from the skin incision,

and more superficially

inserted drain should

lie closer to the

skin incision”


pressure in a controlled manner. Fluids are col-lected in a disposable receptacle. Sponge shouldbe changed every second day initially, as long asfurther cleaning or debridement is necessary, andthen every fourth or fifth day until the wound hashealed or is ready for skin grafting. Superficial skinreactions to adhesive drape and pressure necrosisof skin around drain if precaution is not taken whileapplying the drape are some of the complicationsseen with vacuum sealing. The vacuum-assistedtherapy system is a valuable and effective tool inthe management of patients with difficult woundand several studies have reported promising re-sults.

REINFUSION DRAINReinfusion drain is one of the strategies of autolo-gous blood transfusion. It is a closed suctiondrainage system that allows blood drained fromthe wound post operatively to be collected into atransfusion bag. The collected blood can then bere-infused intra-venously through a filter directlyinto the patient. These systems effectively filterlipid particles and leukocytes from salvaged bloodpreventing possible adverse reactions of reinfusionsuch as fat embolism syndrome, febrile reactions,and pulmonary dysfunction. Studies have dem-onstrated the safety and efficacy of these systemsin reducing the need for allogeneic transfusionand associated adverse reactions, including vari-ous types of infections.16,17

CURRENT LITERATURE REVIEW ON THE USEOF DRAINThough the use of drains for evacuating purulentmaterial or for use in contaminated surgical fieldsis firmly established, its use in clean surgicalwounds is controversial. Various randomised con-trol trials and prospective studies18-22 involvinggeneral orthopaedic surgeries and hip and kneearthroplasty have shown that there is no differ-ence in the outcome between drained andnondrained surgical wounds. In a metaanalysis ofthirty-six studies comparing the use of closedsuction drainage systems with no drainage sys-tems for all types of elective and emergency ortho-paedic surgery, Parker et al23 concluded that therewas no statistically significant difference in theincidence of wound infection, haematoma, dehis-cence or re-operations between those allocated todrains and the un-drained wounds. However, bloodtransfusion was required more frequently in thosewho received drains whereas the need for rein-forcement of wound dressings and the occurrenceof bruising were more common in the group with-out drains. Holt et al24 believe that simple wound

drain effectively minimises the undesirable accu-mulation of blood in the surrounding soft tissues.Further studies with adequate sample size arerequired to clarify the uncertainty about the use ofsuction drains after clean surgical wounds.

REFERENCES1. Price J. Drainage in abdominal surgery. Tr Am Ass Obst

Gynec 1888;1:84.2. Moss JP. Historical and current perspective on surgical

drainage. Surg Gynecol Obstet 1981;152:517-27.3. Waugh T, Stinchfield F. Suction drainage of orthopedic

wounds. J Bone Joint Surg Am 1961;43-A:939-46.4. Gibson CL. The rubber dam Mikulicz tampon. Ann Surg

1921;73:470-4725. Robinson JO, Brown AA. A new closed drainage system.

Br J Surg 1980;67:299-300.6. Wirbel R, Mutschler W. Postoperative wound drainage in

surgery of the locomotor system. Orthopedics and Trauma-tology 2001;9:290-5.

7. Willemen D, Paul J, Crook DW. Closed suction drainagefollowing knee arthroplasty–effectiveness and risk. ClinOrthop 1991;264:232-4.

8. Jepsen OB, Larsen SO, Thomsen VF. Post-operative woundsepsis in general surgery. An assessment of factorsinfluencing the frequency of wound sepsis. Acta Chir ScandSuppl 1969;396: 80.

9. Lidwell OM. Sepsis in surgical wounds. Multiple regressionanalysis applied to records of post-operative hospitalsepsis. J Hyg (Camb) 1961;59: 259.

10. Magee C, Rodeheaver GT, Golden GT, Fox J, Edgerton MT,Edlich RF. Potentiation of wound infection by surgical drains.Am J Surgery 1976;131:547-9.

11. Roy N, Smith M, Anwar M, Elsworth C. Delayed release ofdrain in total knee replacement reduces blood loss. Aprospective randomised study. Acta Orthop Belg2006;72(1):34-8.

12. Brueggemann PM, Tucker JK, Wilson P. Intermittent clamp-ing of suction drains in total hip replacement reducespostoperative blood loss: a randomized, controlled trial. JArthroplasty 1999;14(4):470-2.

13. Fleischmann W, Becker U, Bischoff M, Hoekstra H. Vacuumsealing: indication, technique, and results. Euro J OrthopSurg Traumatol 1995;5:37-40.

14. Argenta LC, Morykwas MJ. Vacuum-assisted closure: a newmethod for wound control and treatment: clinical experience.Ann Plast Surg 1997;38(6):563-76.

15. Armstrong DG, Lavery LA. Negative pressure woundtherapy after partial diabetic foot amputation: a multicentre,randomized controlled trial. Lancet 2005;366:9498,1704-10.

16. Cheng SC, Hung TS, Tse PY. Investigation of the use ofdrained blood reinfusion after total knee arthroplasty: aprospective randomised controlled study. J Orthop Surg(Hong Kong) 2005;13(2):120-4.

17. Jones HW, Savage L, White C, Goddard R, Lumley H, KashifF, et al. Postoperative autologous blood salvage drains—arethey useful in primary uncemented hip and knee arthro-plasty? A prospective study of 186 cases. Acta Orthop Belg2004;70(5):466-73.

18. Acus RW, Clark JM, Gradisar IA, Kovacik MW. The use ofpostoperative suction drainage in total hip arthroplasty.Orthopedics 1992;15:1325-8.

19. Beer KJ, Lombardi AV, Maliory TH, Vaughn BK. The efficacyof suction drains after routine total joint arthroplasty. J BoneJoint Surg Am 1991;73A:584-7.

20. Browett JP, Gibbs AN, Copeland SA, Deliss U. The use ofsuction drainage in the operation of meniscectomy. J BoneJoint Surg Br 1978;60B:516-19.

21. Cobb JP. Why use drains? J Bone Joint Surg Br1990;72B:993-95.

22. Cruse PJE, Foord R. A five-year prospective study of 23,649surgical wounds. Arch Surg 1973;107:206-10.

23. Parker MJ, Livingstone V, Clifton R, McKee A. Closedsuction surgical wound drainage after orthopaedic surgery.Cochrane Database of Systematic Reviews2007(3):CD001825.

24. Holt BT, Parks NL, Engh GA, Lawrence JM. Comparison ofclosed-suction drainage and no drainage after primary totalknee arthroplasty. Orthopedics 1997;20(12):1121-4.

“Blood transfusion

was required more

frequently in those

who received drains

whereas the need for

reinforcement of

wound dressings and

the occurrence of

bruising were more

common in the group

without drains”


INTRODUCTION

Although the combination of a metaphyseal anddiaphyseal radius fracture is uncommon, it is usu-ally caused by high energy. The current genera-tion of volar, fixed-angle plates for the radius arenow available in lengths that can adequately ad-dress most, if not all, fractures of this type. How-ever, situations can and do arise in which thesespecial implants are not available or not applica-ble. Authors suggest an alternate method of man-aging this combination of injuries. By using alimited contact-dynamic compression plate (LC-DCP) stacked on a T-shaped plate, both the meta-physeal and diaphyseal fractures can be ad-equately addressed.

CASE REPORT

A 42- year-old male carpenter, was involved in amotorcycle accident, injuring his dominant rightforearm and wrist. He immediately developed se-vere pain in the forearm and wrist. There was noopen wound, his compartments were soft, and thedistal neurovascular exam was normal. Radio-graphs revealed a comminuted fracture of the

radial shaft at the junction of the middle and distalthirds, with a fracture line extending into the radio-carpal joint, accompanied by an articular stepoff(AO type C2.3) (Fig. 1). There was no obviousevidence of an associated carpal injury.

Metadiaphyseal Fractures ofthe Distal Radius – Managedby Stacked Plating

COMPLEX TRAUMA

M SHANTHARAM SHETTY*

M AJITH KUMAR*

*Senior Consultant

Orthopaedic Surgeon

JAGADISH PRABHU

Senior Resident

Deptt. of Orthopaedics,Tejasvini Hospital andSSIOT, Kadri, Mangalore

Keywords: Stacked plating, Metadiaphysealfractures, Radius

ABSTRACT

Combined injuries of the distal radius and shaft are rare, are usually caused by highenergy and pose a surgical dilemma. Surgical tactics and implants that are routinelyused either for isolated fractures of the distal radius or for fractures of the radial shaft,are often not applicable for this combined injury. We describe a technique of dual-stacked plating for these metadiaphyseal fractures.

Fig. 1: Preoperative radiographic picture

showing metadiaphyseal fractures of the

distal radius (L) AO type C2.3

“Although the

combination of a

metaphyseal and

diaphyseal radius

fracture is uncommon,

it is usually caused by

high energy”


(Fig. 3 A, B). He had no complaints and hadreturned to his previous occupation.

DISCUSSION

Double plating of tibial and femoral fractures hasbeen reported in the literature.1-3 As we mentionedsuch fractures can be managed by using currentgeneration of volar, fixed-angle plates for the ra-dius which are available in different lengths, thatcan adequately address most, if not all, fracturesof this type.

LC-DCPs have a linear design and cannot be usedto adequately fix periarticular fractures by them-selves. These plates are ideal for fixation of dia-physeal fractures in the forearm and are associ-ated with excellent outcomes. By combining thesetwo plates and stacking them, it was possible toachieve stable, independent, yet combined fixa-tion of both these fractures. The application of anadditional plate does increase operative time byabout 30 minutes. However, in our opinion, theadditional fixation and operative time are to bestrongly considered to optimise fixation and toimprove strength of the construct.

It is essential that both plates accept screws of thesame size for adequate fixation to be achieved.There is certainly some concern about increasingthe volume of the forearm by stacking plates andabout the effect this may have on performing atension-free wound closure. However, in our casewe did not have such problem. There is alsoconcern regarding forearm rotation by increasingthe effective thickness of the radius.

Our intention is not to suggest that this is the onlyway to stabilise these complex injuries. Currently,we use special plates that are specifically de-signed for fixation of these complex metadiaphysealfractures. However, such implants may not beavailable (Fig. 4) in emergent situations such as anopen fracture or the accidental propagation of adiaphyseal fracture into the articular surface.

Therefore, we feel that dual-stacked plating is auseful technique to adequately address this com-plex but uncommon combination of fractures andthat this technique can be applied successfully.

REFERENCE1. Ruoff AC III, Biddulph EC. Dual plating of selected

femoral fractures. J Trauma 1972;12:233-41.2. Jergensen F. Double plating of tibial fractures.

Clin Orthop 1974;105:240-52.3. Christodoulou A, Ploumis A, Terzidis I, et al.

Fixation of distal tibial fractures with intra-articularextension using double overlapping plates. Ortho-paedics 2004;27:1155-8.

Fig. 2: Post-op radiographic picture

showing fixation of fracture with stacked

plating technique

Figure 3 A, B: Clinical picture demonstrating the range of wrist motion

A B

“LC-DCPs have a linear

design and cannot be

used to adequately fix

periarticular fractures

by themselves”

100

mm

120

mm

140

mm

Fig. 4: Special AO plates

designed for fixation of

complex metadiaphyseal

fractures

Patient underwent open reduction and internalfixation. The radial shaft fracture was noted toshow comminution with free, well vascularisedbony fragments. The articular component wasinitially neutralised using interfragmentary screwcompression, and the distal radius fracture wasfixed with a T plate using 3.5 mm screws. The platewas noted to provide adequate fixation in themetaphysis but was inadequate in length to se-curely fix the shaft fracture. To augment fixationproximally, a 3.5 mm DCP was stacked on the Tplate. The LC-DCP was fixed to the metaphysealfragment with screws that traversed both plates(Fig. 2). He was splinted in a long-arm posteriorsplint for a few days for comfort and then startedin an early range-of-motion program.

RESULT

By 12 weeks, radiographic union was evident. Athis final follow-up at 1 year, the patient had 80degree pronation, 80 degree supination, 80 degreewrist extension, and 70 degree wrist flexion


Pioneers in OrthopaedicsPIONEERS IN ORTHOPAEDICS

BHAVUK GARG

Sr. Research Associate

RAJESH MALHOTRA

Professor


AIIMS, New Delhi

Astley Cooper was born at the village of Brookein Norfolk on 23 August 1768. His father,Dr. Samuel Cooper, was a clergyman of the Churchof England; his mother was the author of severalnovels. At the age of sixteen he was sent toLondon and placed under Henry Cline (1750-1827), surgeon to St. Thomas’ Hospital. From thefirst he devoted himself to the study of anatomy,and had the privilege of attending the lectures ofJohn Hunter. In 1789 he was appointeddemonstrator of anatomy at St. Thomas’s Hospital,where in 1791 he became joint lecturer with Clinein anatomy and surgery, and in 1800 he wasappointed surgeon to Guy’s Hospital on the deathof his uncle, William Cooper.

In 1802 he received the Copley Medal for twopapers read before the Royal Society of Londonon the destruction of the tympanic membrane; andin 1805 he was elected a Fellow of that society. Inthe same year he took an active part in the formationof the Medical and Chirurgical Society of London,and in 1804 he brought out the first and in 1807 thesecond, part of his great work on hernia, whichadded so largely to his reputation that in 1813 hisannual professional income rose to 21,000 poundssterling. In the same year he was appointedprofessor of comparative anatomy to the RoyalCollege of Surgeons and was very popular as alecturer.

In 1817 he performed his famous operation of tyingthe abdominal aorta for an eurysm; and in 1820 heremoved an infected sebaceous cyst from thehead of King George IV. About six monthsafterwards received a baronetcy, which, as he hadno son, was to descend to his nephew and adoptedson, Astley Cooper. He was subsequentlyappointed sergeant surgeon to King George IV,King William IV and Queen Victoria. He served aspresident of the Royal College of Surgeons in 1827and again in 1836, and he was elected a vice-president of the Royal Society in 1830. He died on12 February 1841 in London.

Sir Astley’s greatest contribution has probably

been in the field ofvascular surgery, parti-cularly on cerebralcirculation. He was thefirst to demonstrateexperimentally theeffects of bilateralligation of the carotidarteries in dogs and topropose treatment ofaneurysms by ligation ofthe vessel. In 1805 hepublished in the first volume of Medico-ChirurgicalTransactions his attempt to tie the common carotidartery for treating an aneurysm in a patient. In 1808he tried the same with the external iliac artery fora femoral aneurysm and in 1817 he ligated the aortafor an iliac aneurysm.

Cooper was an indefatigable and original anato-mist and described several new anatomical struc-tures, many of which were named after him:� Cooper’s fascia, a covering of the spermatic

cord.� Cooper’s pubic ligament, the superior pubic

ligament.� Cooper’s stripes, a fibrous structure in the

ulnar ligaments.� Cooper’s ligaments, the suspensory ligaments

of the breasts.He also described a number of new diseases,which likewise became eponymous:� Cooper’s testis (neuralgia of the testicles)� Cooper’s disease (benign cysts of the breast)� Cooper’s hernia (retroperitoneal hernia)� Cooper’s neuralgia (neuralgia of the breast)He made several other valuable contributions tothe development of surgery detailed in the follow-ing books:� Treatise on dislocations and fractures of the

joints (1822)� Lectures in the principals and practices of

surgery (1824-1827)� Illustrations of the disease of the breast (1829)� Anatomy of the thymus gland (1832)

“He was subsequently

appointed sergeantsurgeon to King George

IV, King William IV and

Queen Victoria”

Sir Astley Cooper(1768-1841)


ORTHO QUIZ-20

ORTHO QUIZ

Question: Discuss the most probable diagnosis.

BHAVUK GARG


RAJESH MALHOTRA

Professor


AIIMS, New Delhi

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CASE HISTORY

A 20 year old lady presented with history of recent trauma to her left ankle. On examination she hasswelling around ankle as well as tenderness, most marked on anterior aspect. AP and mortise view ofthe ankle are shown below.

Fig. 1 Fig. 2


Answer and Discussion to

Ortho Quiz 19

ORTHO QUIZ

BHAVUK GARG


RAJESH MALHOTRA

Professor


AIIMS, New Delhi

Answer to Ortho Quiz 2009 No. 19

Carpal Coalition

Carpal coalition is a rather common, asymptomaticcondition which may occur in association with acongenital syndrome but more commonly is anisolated finding. The syndromes in which carpalcoalition has been described includearthrogryposis, Ellis-van Creveld syndrome, Holt-Oram syndrome, Turner’s syndrome, among oth-ers. In addition, many carpal coalitions are familial.The most common site of coalition is between thelunate and triquetrum. Less common fusion anoma-lies include trapezium-trapezoid, capitate-hamate,and hamate-pisiform. The coalition may not beeasily identifiable owing to the fact that many areincomplete. The majority, however, will demon-strate osseous fusions.

The incidence in the white population is about0.095% but it can be 100 times higher in blacks, andtwo times higher in females than in males. It is oftenbilateral.

AETIOLOGY

Carpal coalition is secondary to a developmentalabnormality. It is believed to be due to a delay inthe natural programmed cell death leading to jointcavitation. Failure of differentiation of the indi-vidual carpal bones results in congenital fusions.However, the term “fusion” should be avoided

Since we have not received any correct entry thereare no winners this time

because the process that has occurred is a failureof segmentation of the cartilaginous precursors ofthe two bones rather than the joining of twopreviously distinct structures.

Fracture or pseudarthrosis formation is unlikelywithout any history of trauma or local symptoms.Furthermore, the absence of any joint space dem-onstrated by arthrography should eliminate non-union, pseudarthrosis, or arthritis as a cause.Similarly, the continuity of articular cartilage acrossthe proximal aspect of the lunate and triquetrumsupports the theory of absent joint formation.

During normal development, the interzone be-tween rudimentary centers of chondrification formsthree distinct layers: a central loose layer repre-senting the future synovium and intracapsularstructures, and two denser zones representing thefuture articular cartilages. If formation of the cen-tral layer does not occur, absence of a normal jointwould be the expected result. Garn et al suggestthat the start of programmed cellular death thatleads to joint cavitation and cartilage separationmay be delayed, thus preventing separation fromproceeding to completion. If normal separationoccurs only along a small portion of the joint, acleft within the bony mass is created.

“The most common

site of coalition is

between the lunate andtriquetrum”


CLINICAL AND RADIOLOGICAL FEATURES

Carpal coalition usually presents without anyobvious clinical symptoms and may occasionallybe associated with any skeletal or functional handdeficiency. The evaluation of this rare entity isvery easy with conventional radiographs as wellas with MRI axial and coronal T1- weighted im-ages.

The appearance of the coalition is variable; thebony mass usually has uninterrupted corticalmargins although a partial cleft is often present ateither the proximal or distal portion of the coalitionsite. Occasionally, there is only narrowing of theapparent space between the two bones withoutactual bony fusion.

Coalition of the carpal bones is not alwaysradiologically complete. The lunate-triquetral coa-litions are divided into four categories accordingto the degree of fusion and the associated anoma-lies. The same classification could be applied toany other carpal coalition:

Type I: An incomplete fusion resembling a pseu-darthrosisType II: Proximal osseous bridge with distalnotchType III: Complete fusionType IV: Fusion with other associated carpalanomalies

TREATMENT

Usually this condition is asymptomatic and re-quires no treatment except reassurance. Completesurgical fusion can be done in recalcitrant cases,if conservative treatment fails.

REFERENCES

1. Resnick C. Incomplete carpal coalition. AJR1986;147:301-4.

2. Resnick D. Diagnosis of bone and joint disorders.W. B. Saunders, Philadelphia; 1988:3560-3561.

3. Simmons BP, McKenzie WD. Symptomatic carpalcoalition. J Hand Surg 1985;10-A:190-93

4. Verdan C. Anomalies of muscles and tendons inhand and wrist. Rev Chir Orthop 1981:67:221-30.

5. Cockshott WP. Carpal fusions. AJR 1963;89:1260-71.

“The evaluation of this

rare entity is very

easy with conventionalradiographs as well as

with MRI axial and

coronal T1- weightedimages”

“Usually this conditionis asymptomatic and

requires no treatment

except reassurance”

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