Septic Arthritis
A joint-destroying emergency in which bacteria seed the synovium and, unrestrained by a poor local immune barrier, trigger a bacterial-and-host enzymatic assault that can destroy cartilage within days.
First principles
The synovium is a poor defence against bacteria once seeded
Bacteria reach a joint by haematogenous spread (the commonest route, especially in native joints), by direct inoculation (trauma, injection, surgery) or by spread from adjacent osteomyelitis. The synovium has a rich blood supply but no basement membrane, so once organisms arrive they pass easily into the joint space, and the enclosed, avascular cartilage that follows offers little protection and poor access for host defences or antibiotics. This anatomical vulnerability is why septic arthritis, once established, escalates rapidly rather than smouldering.
Educational content pending clinical review. Not medical advice.