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Septic arthritis of the DIP joint is a common sequela to chronic infectious processes involving the hoof and/or interdigital space. Examination findings include a swollen coronary band with a draining tract occurring at the dorsal aspect of the extensor process, diffuse swelling of the pastern area, and partial or complete non‐weight‐bearing lameness. Radiographs will reveal osteomyelitis of the coffin joint and increased joint space, with osteolysis of the second and third phalanx (Figure 16.14).

Figure 16.14 Sepsis of the DIP joint with sequestrum formation.

To block the hoof and provide postsurgical analgesia, perform regional limb perfusion using a long‐acting local anesthetic, such as mepivacaine or bupivacaine. The following surgical approach to the DIP joint is preferred over the abaxial approach because it allows better exposure of the joint [5]. Closely trim the sole and heel area and disinfect with surgical scrub and alcohol. A full‐thickness incision is made through the heel and continuing through the deep flexor tendon to expose the intra‐articular area between the navicular bone and the proximal extent of the caudal portion of the coffin bone. It is recommended that the navicular bone be removed. A half‐inch drill is used to facilitate curettage of the joint surface, drilling from the heel incision toward the extensor process and following the surface of the joint [6]. Further debridement of the joint is necessary using a large bone curette. Curettage is complete when you can't remove any more necrotic bone. Use a squeeze bulb to lavage the surgical site with a broad‐spectrum antibiotic or antiseptic saline solution. Place a wooden block on the healthy claw, pack the joint with medical‐grade honey, and bandage the hoof [7] (Figure 16.15).

Figure 16.15 Dressing change post DIP joint currretage. Notice the gauze packing ingress at location of the extensor process of the third phalanx and eggress at the heel bulb.

Parenteral antibiotics are administered daily, and bandage changes and joint lavage are performed every other day up to four times. Beads of bone cement mixed with an antibiotic can be placed in the joint space to facilitate healing, but they should not be placed until there is a healthy granulation bed and no more purulent discharge. When the surgical wound has closed with granulation tissue, the limb is casted above the fetlock for five to six weeks. After the cast and hoof block are removed, the animal should have a recuperative period. The patient should show at least 80% improvement in lameness over the initial presentation after the convalescent period; some lameness is to be expected.