BONE AND JOINT INFECTION

Dr.Syed Alam Zeb

AETIOLOGY

Staphylococcus aureus is overall the most common.

• Beta haemolytic streptococci and anaerobes may cause acute infection.

• E-coli and B. streptococci are more common in children.

• Aerobic gram negative rods may cause infection in the elderly.

PATHOGENESIS OF BONE AND JOINT INFECTION

• Healthy bone is resistant to infection.

• Open fractures provide an ideal focus for infection.

• Organisms can lie latent in dead bone(sequestrum).

• Involucrum is healthy new bone formed in a shell around dead and infected bone.

ACUTE SEPTIC ARTHRITIS

• The history is short with the patient generally very unwell.

• Young children do not move the involved limb.

• In older patients the joint is extremely painful to move.

• The affected limb is hot and red.• Night and rest pain are characteristic.

ACUTE OSTEOMYELITIS

• Present like acute arthritis.

• There is fever, loss of function and localized pain.

• In young children the presentation may simply be refusal to weight bear or use a limb.

• The affected part is hot, tender and red.

CHRONIC OSTEOMMYELITIS

• Usually follow an episode of acute infection or an open fracture.

• Pain at rest especially night pain.

• Swelling, ulcer or sinus may be present.

• Bony tenderness is common.

• Systemic features are minimum.

DIABETIC FOOT OSTEOMYELITIS

• Neuropathy, vasculopathy and high blood sugar leads to ulcer formation.

• Bones become secondarily involved.• Chronic non-healing infection result in soft

tissue and bony loss.• Control of diabetes, improving the

nutritional status and regular debridements are required.

Investigations for acute osteomyelitis and septic arthritis

• WBC count and CRP are high, ESR may be very high.

• Changes on plain x-rays are not visible for some time.

• US can pick pus.

• Isotope scans are sensitive but not specific.

Investigations for acute osteomyelitis and septic arthritis

• CT may show bone erosions.

• MRI is very helpful.

• Culture and sensitivity is invaluable.

• Histology of infected bony tissue sometimes required.

MANAGEMENT

Osteomyelitis

• In acute osteomyelitis put the patient on iv antibiotics and pain killers.

• Early diagnosis reduces the risk of infection becomes chronic.

• Surgery required to remove infected tissues and to obtain material for culture.

Chronic Osteomyelitis

• When acute infection is not treated properly it can lead to destruction of bone.

• The combination of dead bone with pus formation and discharging sinuses on the skin is called Chronic osteomyelitis.

• Treatment is debridement of the dead bone and soft tissues and regular cleaning.

Septic Arthritis

• Joints should be aspirated before treatment is started.

• Antibiotics started empirically then changed according to the culture results.

• Treatment should last several weeks starting with iv antibiotics.

• If infection recurs the joint may need to be opened and any loculi washed out.

Chronic arthritis

• All dead and foreign tissues must be excised

• Secure implants may be left but all suspect soft tissues must be excised.

• Antibiotic- impregnated beads or spacer may be put in to the joint space.

• Blood levels of antibiotic needs regular checking.