A long digital extensor tendon avulsion is reported in a 15-month-old intact male Great Dane with aright pelvic limb lameness of 2-week duration. The orthopedic, radiographic, computed tomographic, arthroscopic,surgical and histological findings are described. Surgical excision of the avulsed bone fragmentand re-attachment of the tendon to the lateral joint capsule of the stifle joint was successful and the dogwas free of lameness 6 and 12 months after therapy.