Ulnar fracture and dislocation of the proximal radial epiphysis (Monteggia lesion) in the dog and cat: a review of 28 cases.

Ulnar fracture with dislocation of the proximal epiphysis of the radius (Monteggia lesion) was diagnosed in 16 dogs and 12 cats. The lesions were classified into 4 types on the basis of direction of the dislocation of the radial head and angulation of the ulnar fracture. Cranial dislocation of the radial head, with cranial angulation of the ulnar fracture (type 1 lesion) was the most common. Radial head chip fractures were frequently associated with the lesions. In 25 cases, open reduction and internal fixation were required. The most common postoperative complications were restricted range of motion in the elbow, osteoarthritis, and recurrent dislocation of the radial head. Follow-up evaluations in 16 cases revealed good to excellent results in 10 animals and fair to poor results in 6 animals.