Shoulder injury A mature Shetland pony presented with lameness on the left forelimb. Pain was noted on extension/flexion of the shoulder joint. Lateral radiographs were made of both shoulders. Two views of the left shoulder Radiographic changes Changes are typical for chronic secondary joint disease
- Periarticular osteophyte formation from the caudal aspect of the glenoid cavity
- New bone production on the cranial aspect of the glenoid cavity
- Possibility of chronic fracture involving the cranial part of the glenoid or injury to the lesser tubercle
- Malshapen humeral head
- Periarticular osteophyte formation from the caudal aspect of the humeral head
Comparison of the left and right shoulders permits identification of the new bone production on the left Radiographic diagnosis
- Secondary joint disease can be the result of a variety of injuries
- The more chronic the changes, the more difficult to select a definitive etiology
- The changes in this Shetland are limited to one shoulder tending to lessen the possibility of a developmental lesion such as osteochondrosis
- The suggestion of injury to the tubercle and cranial part of the glenoid suggest direct trauma
- The change in shape of the humeral head suggests chronic injury with instability of the shoulder leading to modeling
Comments
- Radiographic studies of the shoulder are limited to lateral and oblique views
- Caudocranial views made with the patient in dorsal recumbency area difficult and are usually of limited value in diagnosis
- The absence of destructive changes tends to rule out osteomyelitis or infectious arthritis
- Evaluation of the width of the joint space is usually of little value in the horse • Evaluation of the subchondral bone is usually difficult in the shoulder
- The mature appearance of the new bone suggests
