Cast immobilization for treatment of dorsally subluxated proximal interphalangeal joint in a Thoroughbred mare

Subluxation of the proximal interphalangeal joint (PIPJ or pastern joint) is an uncommon condition that occurs in the forelimb or hindlimb. Thoroughbred racehorses rarely show dorsal pastern subluxation (Thoroughbred ringbone) secondarily to an injury to the soft tissues supporting the fetlock. A 4-year-old Thoroughbred mare was presented with signs of lameness, swelling of the dorsal aspect of the pastern region of the right forearm and audible clicking sound when weight was placed on the limb. The condition seemed to have been developed as a consequence of extreme overexertion 4 days before referral. Radiographic examination of a non-weight bearing limb showed dorsal subluxation of the pastern joint. Under general anesthesia the affected limb was immobilized by cast after reduction of the luxated bone into the PIPJ. The affected limb was kept immobilized for four weeks. Then the cast was removed and the animal was given rest for two months. Consequently, weight bearing on the affected limb was improved and no signs of lameness were observed after six months.