Proximal focal humeral deficiency in a large breed dog.

A 26-week-old female Boerboel was referred for evaluation of progressive left thoracic limb lameness. Computed tomography and radiographic evaluation revealed radiolucency of the caudal region of the proximal humeral metaphysis, absence of the humeral head, and gross distortion of the glenoid. Given the severe glenohumeral deformation, arthrodesis of the left shoulder was performed using orthogonal locking bone plates, lag screw fixation, and bone grafting. Despite late implant failure, arthrodesis was successful in this case, and satisfactory limb function was restored. To the author's knowledge, this is the first report of a case of a focal developmental deficiency of the proximal humerus reported in a dog.