AVULSION FRACTURE OF THE ORIGIN OF THE EXTENSOR DIGITORUM LONGUS MUSCLE IN A FOAL

A 9-week-old Thoroughbred x Holsteiner colt was referred for evaluatio n and treatment of lameness of the right hind limb. Radiography of the stifle revealed multiple bony fragments within the lateral portion of the femorotibial joint and a radiolucency of the distolateral portion of the femur in the area of the extensor fossa, which were consistent with avulsion of the origin of the extensor digitorum longus muscle. Arthroscopy of the lateral portion of the femorotibial joint revealed exposed subchondral bone in the area of the extensor fossa, and the or igin of the extensor digitorum longus muscle was determined to be avul sed. The joint was lavaged, and fibrin and fragments of cartilage and bone were removed from the joint. Six months after surgery, the horse appeared normal during trotting and cantering.