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

The research paper revolves around the treatment of a young horse suffering from joint infections (septic arthritis and septic navicular bursitis) following foot injury, where the aim of the treatment was joint fusion (ankylosis) to manage persistent sepsis in the joint.

Background of the Case

• The case involved a 300-kg, 6-month old horse of the Quarter breed, affected with septic arthritis of the distal interphalangeal joint and septic navicular bursitis. These conditions had developed as a result of a deep puncture wound in the filly’s foot.

Initial Treatment

• Early intervention included establishing ventral drainage for the infected navicular bursa, thoroughly cleaning (lavage) of the distal interphalangeal joint, administration of broad-spectrum antimicrobials to manage the sepsis, and non-steroidal anti-inflammatory drugs (NSAIDs) to control inflammation and pain.

Subsequent Treatment due to Continuing Sepsis

• Additional treatment was necessitated by the persistence of the infection. This included packing the foot defect with cancellous bone to prevent the upward spread of the infection, immobilizing the limb in a compact cast, and placing a Penrose drain in the joint for passive drainage of accumulated, infected fluid (septic exudate).
• The ultimate target of the treatment was to encourage the joint to become stiff and immobile (ankylosis) to manage the continuing sepsis effectively.
• To promote weight-bearing despite persistent lameness and looseness of the lateral collateral ligament in the filly’s other paster’s joint (contralateral carpus), the palmar nerves of the affected foot were injected with a long-working local anesthetic at the level of the proximal sesamoid bones.

Outcomes

• After nine months since the puncture, complete ankylosis of the distal interphalangeal joint was achieved. Unfortunately, the horse still exhibited a grade-2 lameness and had a varus deformity. This resulted from ligamentous laxity of the lateral collateral ligament in the contralateral carpus, an issue not directly associated with the initial injury but that nevertheless affected the horse’s mobility and condition.