OR3.1 | Bone and Joint Infection Assessment — Summary & Reflection

KEY TAKEAWAYS

Bone and joint infections span a clinical spectrum from rapidly destructive emergencies (acute osteomyelitis, septic arthritis) to indolent chronic diseases (Brodie's abscess, chronic osteomyelitis, skeletal TB). The metaphysis is the preferential site of haematogenous seeding due to sluggish capillary flow and absent phagocytic lining. Key pathological landmarks — sequestrum (dead avascular bone), involucrum (reactive periosteal new bone), Brodie's abscess (walled-off subacute abscess with surrounding sclerosis), cold abscess (hallmark of TB) — each have diagnostic and management implications. Plain radiograph changes lag behind clinical disease by 7-10 days; MRI is the early gold standard. Management of septic arthritis is a surgical emergency (urgent arthrotomy). Chronic osteomyelitis requires sequestrectomy and saucerisation because antibiotics cannot reach avascular dead bone. The key clinical discriminator between pyogenic and TB infection is tempo: pyogenic is acute with high fever and elevated CRP/WBC; TB is indolent with constitutional symptoms, cold abscess, and a subacute radiological picture.

REFLECT

Consider a 35-year-old farmer who presents to your district hospital with a 6-month history of gradually worsening right thigh pain, a draining sinus on the anterolateral thigh, and moderate weight loss. His X-ray shows a dense bony fragment (sequestrum) within a cavity, surrounded by a thick bony shell (involucrum). Blood tests show ESR 90 mm/h, CRP 45 mg/L, WBC 11,000/μL, and Mantoux test is strongly positive. How would you approach this case — and at which point would you request surgical consultation versus starting anti-TB therapy? What investigations would you order to differentiate pyogenic chronic osteomyelitis from TB osteomyelitis, and how would that differentiation change your management plan?