Accessory carpal bone fracture repair by means of computer-assisted orthopaedic surgery in a Warmblood stallion

A 10-year-old, 595 kg Irish Warmblood stallion used for showjumping was presented with a marked right forelimb lameness at walk. The horse sustained a dorsal plane fracture of the accessory carpal bone (ACB) when falling with both carpi in flexion. The fracture was repaired by means of computer-assisted orthopaedic surgery (CAOS) using two cortex screws placed in lag fashion. In a second CAOS procedure, a dorsoproximal fragment of the ACB was removed after further proximal displacement had become apparent. Both surgical procedures were facilitated by the application of a fibreglass cast to immobilise the carpus in extension and to allow for the placement of the patient tracker distant from the surgical site. One year after surgery, the horse had returned to full athletic activity. Neither the antebrachiocarpal joint nor the carpal sheath were distended. Control radiographs and standing cone beam computed tomography showed complete osseous union of the fracture and osteophyte formation on the caudal aspect of the radius and the proximal border of the ACB.