Three cases of accessorioulnar arthrodesis to address accessory carpal bone subluxation or fracture

ACCESSORIOULNAR (AU) arthrodesis (AU-AD) has been reported in dogs only once in the literature, to address accessory carpal bone (ACB) subluxation (Lenehan and Tarvin 1989). It is an infrequently performed procedure in British veterinary clinics. A request for such cases was made directly to 121 British veterinary surgeons accepting orthopaedic referrals and also published in Veterinary Record (Bush 2010); this generated five cases, although only three had sufficient clinical notes and radiographs to allow inclusion in the present report. A detailed knowledge of carpal anatomy (Mikic and others 1992, Guilliard 2001) is crucial for the evaluation of carpal injuries and for surgical reconstruction. Due to the lack of published reports detailing feline carpal ligamentous anatomy, an assumption is made that the ligamentous structures of the ACB in cats are analogous to those of the dog (Voss and others 2003, Calvo and others 2009) (Fig 1). Fig 1 Schematic diagram of the lateral aspect of the carpus in the dog, showing the principal ligaments of the accessory carpal bone. The accessorioradial ligament originates from the radius and inserts on the medial proximobasilar aspect of the accessory carpal bone (ACB). The accessorioulnar ligament originates from the ulna and inserts on the lateral proximobasilar aspect of the ACB. The accessorioulnar carpal ligament (AU-CL) originates from the lateral distobasilar aspect of the ACB and inserts on the lateral aspect of the ulnar carpal bone (UCB). The accessorioquartile ligament lies medial to this with a small insertion on the UCB but its main insertion on the fourth numbered carpal bone. On the apical (palmar) aspect of the ACB, the flexor carpi ulnaris inserts proximally. The accessoriometacarpal ligaments IV and V (AMCL IV/V) originate from the distoapical border of the ACB and insert at the heads of metacarpals IV and V, respectively. The palmar retinaculum …