BONE, JOINT HAND INFECTIONS

Nur Adzyan Ruhaizad1001335975

• Describe the epidemiology of the bone and joint infection.• Describe and differentiate the clinical features of the bone and joint infection. • Make a diagnosis and a list of differential diagnoses by analysis of clinical

findings in history and physical examination of the patient with bone and joint infection.

• Select appropriate investigation and interpret to confirm the diagnosis, to evaluate the pathological stages of bone and joint infection.

• Plan the provisional management for the bone and joint infection.• Discuss the definitive managements and treatment options depend on the

clinic-pathological stages of bone and joint infections.• Discuss the complications and prevention of bone and joint infection.• Discuss the role of physiotherapy and occupational therapy for rehabilitation.

OST

EOM

YELI

TIS

ACUTE

ACUTE HAEMATOGENOUS

POST TRAUMATIC

CHRONIC

ACUTE HAEMATOGENOUS OSTEOMYELITIS

• Mainly a disease of children• Adults are affected usually because their

resistance is lowered• Causal organism in both adults and children is

usually staphyloccocus aureus (>70%)• Less often one are other Gram-positive cocci :

Group A beta-haemolytic streptococcus (Streptococcus pyogenes) which is found in chronic skin infections

Group B streptococcus (especially in new-born babies) Alpha haemolytic diplococcus S. pneumoniae.

Children

• infection usually starts in the vascular metaphysis of a long bone, most often in the proximal tibia or in the distal or proximal ends of the femur.

• In infants, in whom there are still anastomoses between metaphyseal and epiphyseal blood vessels, infection can also reach the epiphysis.

Adults

• haematogenous infection accounts for only about 20% of cases of osteomyelitis, mostly affecting the vertebrae.

• Staphylococcus aureus is the commonest organism but Pseudomonas aeruginosa often appears in patients using IVDU.

• Adults with diabetes, who are prone to soft-tissue infections of the foot, may develop contiguous bone infection involving a variety of organisms

CLINICAL FEATURES IN CHILDREN

• Severe pain, malaise and fever• In neglected cases, toxaemia may be marked. • The parents will have noticed that he or she

refuses to use one limb or to allow it to be handled or even touched.

• There may be a recent history of infection: a septic toe, a boil, a sore throat or a discharge from the ear.

• Typically the child looks ill and feverish; the pulse rate is likely to be over 100 and the temperature is raised.

• The limb is held still and there is acute tenderness near one of the larger joints (e.g. above or below the knee, in the popliteal fossa or in the groin).

• Even the gentlest manipulation is painful and joint movement is restricted (‘pseudoparalysis’).

• Local redness, swelling, warmth and oedema are later signs and signify that pus has escaped from the interior of the bone.

• Lymphadenopathy is common but non-specific.

• It is important to remember that all these features may be attenuated if antibiotics have been administered.

CLINICAL FEATURES IN ADULTS• The commonest site for haematogenous infection is the thoracolumbar spine.

• There may be a history of some urological procedure followed by a mild fever and backache.

• Local tenderness is not very marked

• May take weeks before x-ray signs appear; when they do appear the diagnosis may still need to be confirmed by fine-needle aspiration and bacteriological culture.

• Other bones are occasionally involved, especially if there is a background of diabetes, malnutrition, drug addiction, leukaemia, immunosuppressive therapy or debility.

• In the very elderly, and in those with immune deficiency, systemic features are mild and the diagnosis is easily missed.

LAB INVESTIGATIONSaspirate pus or fluid from

the metaphyseal subperiosteal abscess, the

extraosseous soft tissues or an adjacent joint.

Even if no pus is found, a smear of the aspirate is

examined immediately for cells and organisms

A sample is also sent for detailed microbiological

examination and tests for sensitivity to antibiotics.

Tissue aspiration will give a positive result in over 60% of

cases; blood cultures are positive in less than half the

cases of proven infection

CRP values are usually elevated within 12–24 hours

after onset of symptoms,

ESR within 24–48 hours after the onset of symptoms.

FBC: The white blood cell (WBC) count rises and the

haemoglobin concentration may be diminished.

IMAGING INVESTIGATION

PLAIN X-RAY• During the first week after the onset of symptoms

the plain x-ray shows no abnormality of the bone.

• By the second week there may be a faint extra-cortical outline due to periosteal new bone formation; this is the classic x-ray sign of early pyogenic osteomyelitis, but treatment should not be delayed while waiting for it to appear.

ULTRASONOGRAPHY • May detect a subperiosteal collection of fluid in the early stages of

osteomyelitis, but it cannot distinguish between a haematoma and pus.

RADIONUCLIDE SCANNING• May show increased uptake, by the bone in the metaphysis. This is

positive before the changes appear on an X-ray. • This is a highly sensitive investigation, even in the very early stages, but it

has relatively low specificity and other inflammatory lesions can show similar changes.

MAGNETIC RESONANCE IMAGING • Helpful in cases of doubtful diagnosis, and particularly in suspected

infection of the axial skeleton. • It is also the best method of demonstrating bone marrow inflammation. It

is extremely sensitive, even in the early phase of bone infection, and can therefore assist in differentiating between soft-tissue infection and osteomyelitis.

• However, specificity is too low to exclude other local inflammatory lesions.

DIFFERENTIAL DIAGNOSIS

• Cellulitis• Acute suppurative arthritis• Streptococcal necrotizing myositis• Acute rheumatic arthritis• Acute septic arthritis• Sickle cell crisis• Gaucher’s disease

TREATMENTPRINCIPLE OF TREATMENT

1) to provide analgesia and general supportive measures2) to rest the affected part3) to identify the infecting organism and administer effective antibiotic treatment

or chemotherapy4) to release pus as soon as it is detected5) to stabilize the bone if it has fractured6) to eradicate avascular and necrotic tissue7) to restore continuity if there is a gap in the bone8) to maintain soft-tissue and skin cover.

Acute infections, if treated early with effective antibiotics, can usually be cured. Once there is pus and bone necrosis, operative drainage will be needed.

TREATMENT

• Early, adequate treatment of acute osteomyelitis is the key to success.

• The child is admitted and investigated.

• Treatment depends upon the duration of illness after which the child is brought. Cases can be arbitrarily divided into two groups:– Brought within 48hours of onset of symptoms– Brought after 48hours of onset of symptoms

Brought within 48hours of onset• It is supposed that pus has not yet formed and the inflammatory

process can be halted by systemic antibiotics.

• REST : The limb is put to rest in a splint or by traction. • ANTIBIOTIC:

– started after taking blood for C&S– choice depends on age of child and choice of doctors. – <4 months old, ceftriaxone + vancomycin – the antibiotic is changed to a specific one depending upon C&S report.

• GENERAL : The child is adequately rehydrated with intravenous fluids.

• The response to the above treatment is evaluated by frequent assessment of the patient.

• A four-hourly temperature chart and pulse record is maintained.

• It is a good idea to outline the area of local tenderness precisely with the help of the back of a match-stick over regular intervals.

• If the patient responds favourably, fever will start declining and local inflammatory signs will diminish.

• As the child improves, the limb can be put to use.

• After 2 weeks, antibiotics can be administered by the oral route for 6 weeks.

• If the patient does not respond favourably within 48 hours of starting the treatment, surgical intervention is required.

Brought after 48 hours of onset

• It is taken for granted that there is already a collection

of pus within or outside the bone. • The detection of pus is often difficult by clinical

examination because it may lie deep to the periosteum.

• An USG examination of affected part may help in early detection of deep collection of pus.

• Surgical exploration and drainage is the mainstay of treatment at this stage.

• A drill hole is made in the bone in the region of the metaphysis. If pus wells up from the drill hole, the hole is enlarged until free drainage is obtained.

• A swab is taken for culture and sensitivity. • The wound is closed over a sterile suction drain. • Rest, antibiotics and hydration are continued post-operatively. • Gradually, the inflammation is controlled and the limb is put

to use. • Antibiotics are continued for 6 weeks.

COMPLICATIONS

• Epiphyseal damage and altered bone growth

• Suppurative arthritis

• Metastatic infection

• Pathological fracture

• Chronic osteomyelitis

POST TRAUMATIC OSTEOMYELITIS

• This is the most common cause of osteomyelitis in adults.

• Open fractures are always contaminated and are therefore prone to infection.

• Tissue injury, vascular damage, oedema, haematoma, dead bone fragments and an open pathway to the atmosphere must invite bacterial invasion even if the wound is not contaminated with particulate dirt.

• Staphylococcus aureus is the usual pathogen, but other organisms such as E. coli, Proteus mirabilis and Pseudomonas aeruginosa are sometimes involved.

• Occasionally, anaerobic organisms (clostridia, anaerobic streptococci or Bacteroides) appear in contaminated wounds.

CLINICAL FEATURES

• Feverish and develops pain and swelling over the fracture site

• Wound is inflamed• May be a seropurulent discharge

INVESTIGATIONS

Blood test : Increased CRP levels, leucocytosis, ESR

X-ray : may be more difficult than usual to interpret because of bone fragmentation

MRI : helpful in differentiating between bone and soft tissue infection. Less reliable in distinguishing longstanding infection and bone destruction due to trauma

Wound swab : Cultured for organisms

TREATMENT

• The essence of treatment is prophylaxis : – through cleansing and debridement of open

fractures– Provision by drainage by leaving the wound open– Immobilization of the fracture and antibiotics

• Regular wound dressing and repeated excision of all dead and infected tissue.

• Traditionally it was recommended that stable implants (fixation plates and medullary nails) should be left in place until the fracture had united, and this advice is still respected in recognition of the adage that even worse than an infected fracture is an infected unstable fracture.

• External fixation techniques have meant that almost all fractures can, if necessary, be securely fixed by that method, with the added advantage that the wound remains accessible for dressings and superficial debridement.

• If these measures fail, the management is essentially that of chronic osteomyelitis.

CHRONIC OSTEOMYELITIS

CHRONIC OSTEOMYELITIS• Used to be the dreaded sequel to acute haematogenous osteomyelitis;

nowadays it more frequently follows an open fracture or operation.

• The usual organisms (and with time there is always a mixed infection) are :– Staphylococcus aureus– Escherichia coli – Streptococcus pyogenes – Proteus mirabilis – Pseudomonas aeruginosa

• In the presence of foreign implants Staphylococcus epidermidis, which is normally non-pathogenic, is the commonest of all

PREDISPOSING FACTORS• Acute haematogenous osteomyelitis, if left untreated , and provided the

patient does not succumb to septicaemia – will subside into a chronic bone infection

• The host defences are inevitably compromised by the presence of scar formation, dead and dying bone around the focus of infection, poor penetration of new blood vessels and non-collapsing cavities in which microbes can thrive.

• These processes are evident in patients who have been inadequately treated (perhaps ‘too little too late’)

• The commonest of all predisposing factors is local trauma, such as an open fracture or a prolonged bone operation, especially if this involves the use of a foreign implant.

PATHOLOGY• When the infection persists, the host bone responds by generating

more and more sub-periosteal new bone.

• This results in a thickening of the bone.

• The subperiosteal bone is deposited in a very irregular fashion so that the osteomyelitic bone has an irregular surface.

• The continuous discharge of pus results in the formation of a sinus. • With time, the wall of the sinus gets fibrosed and the sinus becomes

fixed to the bone.

• Sequestrum is a piece of dead bone, surrounded by infected granulation tissue trying to 'eat' the sequestrum away. – It appears pale, and has a smooth inner and rough outer surface,

because the latter is being constantly eroded by the surrounding granulation tissue.

• Involucrum is the dense sclerotic bone overlying a sequestrum. – There may be some holes in the involucrum for pus to drain out. – These holes are called cloacae– The bony cavities are lined by infected granulation tissue.

CLINICAL FEATURES

• Pain, pyrexia, redness and tenderness(a ‘flare’)

• Discharging sinus

• In longstanding cases the tissues are thickened and often puckered or folded inwards where a scar or sinus adheres to the underlying bone.

• There may be a seropurulent discharge and excoriation of the surrounding skin.

• In post-traumatic osteomyelitis the bone may be deformed or ununited.

INVESTIGATIONSRadiological examination

The following are some of the salient radiological features seen in chronic osteomyelitis:

– Thickening and irregularity of the cortices. – Patchy sclerosis– Bone cavity: This is seen as an area of rarefaction surrounded by sclerosis. – Sequestrum: This appears denser than the surrounding normal bone

because the decalcification which occurs in normal bone does not occur here. The granulation tissue surrounding the sequestrum gives rise to a radiolucent zone around it. A sequestrum may be visible in soft-tissues.

– Involucrum and cloacae may be visible.

Sinogram• May help to localize the site of infection• Radioopaque dye is inserted into sinus and Xray taken.

CT scan and MRI• Show the extent of bone destruction and reactive oedema, hidden

abscesses and sequestra

Blood• ESR, CSR, and WBC levels may be increased ; not diagnostic• Helpful in assessing the progress of bone infection

Pus Culture• Organisms cultured from discharging sinuses• useful for control of the acute stage, or may help in selecting the pre-

operative antibiotics as and when operation is performed.

STAGING• Helps in risk-benefit assessment and has some predictive

value concerning the outcome of treatment.

• The least serious, and most likely to benefit, are patients classified as Stage 1 or 2, Type A, i.e. those with localized infection and free of compromising disorders.

• Type B patients are somewhat compromised by a few local or systemic factors, but if the infection is localized and the bone still in continuity and stable (Stage 1–3) they have a reasonable chance of recovery.

• Type C patients are so severely compromised that the prognosis is considered to be poor.

• If the lesion is also classified as Stage 4 (e.g. intractable diffuse infection in an un-united fracture), operative treatment may be contraindicated and the best option may be long-term palliative treatment. Occasionally one may have to advise amputation.

TREATMENT1. Antibiotics• To suppress the infection and prevent its spread to healthy

bone• To control acute flares• Antibiotics are administered for 4–6 weeks (starting from the

beginning of treatment or the last debridement) before considering operative treatment.

2. Local treatments• Sinus need dressing to protect the clothing• Acute abscess may need urgent incision and drainage

3. Operation indicated if :• Chronic haematogenous infections• Post traumatic infections• Postoperative infection• Presence of foreign implants

OPERATIVE PROCEDURES

a) Sequestrectomy: • This means the removal of sequestrum. • If it lies within the medullary cavity, a window

is made in the overlying involucrum and the sequestrum removed.

• One must wait for adequate involucrum formation before performing sequestrectomy.

b) Saucerization: • A bone-cavity is a 'non-collapsing cavity' so that

there is always some pent-up pus inside it. • This is responsible for the persistence of an

infection. In saucerization, the cavity is converted into a 'saucer' by removing its wall.

• This allows free drainage of the infected material.

c) Curettage: • The wall of the cavity, lined by infected granulation tissue, is curetted until

the underlying normal-looking bone is seen. • The cavity is sometimes obliterated by filling with gentamycin impregnated

beads or local muscle flap.

d) Excision of an infected bone: • In a case where the affected bone can be excised en-bloc without

compromising the functions of the limb, it is a good method e.g., osteomyelitis of a part of the fibula.

• With the availability of Ilizarov's technique, an aggressive approach, i.e., excising the infected bone segment and building up the gap by transporting a segment of the bone from adjacent part has shown good results

e) Amputation: • It may, very rarely, be preferred in a case with a long-standing

discharging sinus, especially if sinus undergoes malignant changes.• In most cases, a combination of these procedures is required. • After surgery the wound is closed over a continuous suction

irrigation system • This system has an inlet tube going to the medullary cavity, and

an outlet tube bringing the irrigation fluid out. • A slow-suction is applied to the outlet tube. • The irrigation fluid consists of antibiotics and a detergent. • The medullary canal is irrigated in this way for 4 to 7 days.

COMPLICATIONS• 1. An acute exacerbation or 'flare up' of the infection • 2. Growth abnormalities:

– Shortening, when the growth plate is damaged. – Lengthening because of the increased vascularity of the growth

plate due to the nearby osteomyelitis.– Deformities may appear if a part of the growth plate is damaged

and the remaining keeps growing.• 3. A pathological fracture• 4. Joint-stiffness • 5. Sinus-tract malignancy • 6. Amyloidosis