Ankylosis of the distal interphalangeal joint in a horse after septic arthritis and septic navicular bursitis.

A 6-month-old 300-kg Quarter Horse filly was treated for septic arthritis of the distal interphalangeal joint and septic navicular bursitis that developed as a result of a deep puncture to the foot. Initial treatment consisted of establishing ventral drainage for the navicular bursa, lavage of the distal interphalangeal joint, and administration of broad-spectrum antimicrobial drugs and non-steroidal anti-inflammatory drugs. Because of continuing sepsis in the distal interphalangeal joint, subsequent treatment included packing the defect in the bottom of the foot with cancellous bone in an attempt to prevent ascending contamination of the joint, placing the limb in a short limb cast, and inserting a Penrose drain into the joint for passive drainage of septic exudate. The goal of treatment was to encourage ankylosis of the distal interphalangeal joint. Because of the filly's persistent lameness and laxity of the lateral collateral ligament in the contralateral carpus, the palmar nerves of the affected foot were injected with a long-acting local anesthetic at the level of the proximal sesamoid bones to encourage weight-bearing. Ankylosis of the distal interphalangeal joint was complete 9 months after the puncture, but a grade-2 lameness remained and the horse had a varus deformity resulting from ligamentous laxity of the lateral collateral ligament in the contralateral carpus.