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02/05/2025
I recently relocated to Saint Francis Veterinary Center where I am hoping to start a specialty surgery service. This case is one of my favorite cases I did at Saint Francis last fall.
Dexter, a very handsome 9 year old Hound X, was presented for evaluation of a chronic progressive RIGHT forelimb lameness and suspected RIGHT supraglenoid tubercle avulsion.
Dexter has been cared for by his owner since puppyhood; when I met him, he had been lame on his RIGHT forelimb intermittently for a few years. The lameness became acutely worse about a month prior to presentation. Dexter’s owner administered Aspirin, but no improvement occurred. Dexter was seen by a general practitioner at Saint Francis. Examination revealed a severe RIGHT forelimb lameness. Blood work was unremarkable aside from hemoconcentration.
Radiographs revealed a large, triangular, smoothly marginated osseous body immediately adjacent to the RIGHT supraglenoid tubercle. It was separated from the tubercle itself by a thin, well-defined lucent cleft. The tubercle was also mildly sclerotic and remodeled. There was minimal osteophyte formation along the caudal aspect of the RIGHT glenoid and humeral head. The RIGHT elbow was radiographically normal. No abnormalities were observed in the included portions of the LEFT thoracic limb. The radiologist concluded that the lesion most likely represented a chronic nondisplaced avulsion fracture of the biceps origin. He noted stress views could be obtained for additional information. Gabapentin and Trazodone were prescribed; Aspirin was discontinued.
Referral was recommended; Dexter was seen at a local specialty hospital and CT was recommended as a first step. Dexter was presented for an alternative opinion.
When I met Dexter, he had Grade II-IV/IV RIGHT forelimb lameness. Pain was noted on palpation of the elbow, shoulder, and biceps. I explained that radiographs seemed consistent with chronic supraglenoid tubercle avulsion. I discussed options for CT scan and fragment removal/biceps tenodesis IF indicated OR fragment removal/biceps tenodesis alone. Owners elected fragment removal/tenodesis alone. I explained that forgoing CT scan may lead to failure to diagnose concurrent lesions, but most of the comorbidities we could uncover would likely not be life limiting and may not significantly affect prognosis.
When Dexter was presented for his procedure, examination was unchanged. Dexter was anesthetized; radiographs revealed slight movement of the supraglenoid fragment during range of motion. A lateral approach to the medial aspect of the proximal humerus was performed. The biceps tendon was identified and released. A bicipital tenodesis was performed using a 24 mm 3.5 mm screw and washer. The supraglenoid fragment was identified. It was moveable but did not easily free up for removal. The fragment was removed with the aid of an osteotome. Fragments were saved for biopsy, however, we are not particularly suspicious of neoplasia. The site was copiously lavaged and closed routinely. Nocita was injected during closure. Dexter did well under anesthesia and recovered without complication. A carpal flexion bandage was placed post-operatively.
The carpal flexion bandage was removed just before 1 week post-operatively; when Dexter was seen for a recheck 2 weeks after surgery, he was grade II/IV lame on his RIGHT forelimb but offloading at rest. At 8 weeks post-operatively, he was no longer lame during motion, but still offloading at rest a bit. Muscle atrophy persisted. Dexter has been seen multiple times since his recovery and his muscle asymmetry seems to have normalized and his offloading has resolved.
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For most surgeons, general practice veterinarians, and dog owners chronic forelimb lameness is a source of frustration.
Forelimb lamenesses are often hard to diagnose. Forelimb lamenesses can occur secondary to diseases of the nerves (cervical disc compression, nerve root tumors), diseases of the bones (bone tumors, fractures), diseases of the joints (OCD of shoulder, elbow dysplasia, should instabilities, luxations, IMPAs), and diseases of the ligaments/tendons/muscles (supraspinatus and biceps tendinopathies, collateral ligament issues). Arthritis contributes but never occurs as a sole disease except in the case of immune mediated disease. While every dog who has a significant forelimb lameness would benefit from being evaluated by a surgeon, examinations don’t always perfectly localize the lameness and the lameness is often multifactorial.
Most forelimb lamenesses require advanced imaging to diagnose. While fractures, bone tumors, arthritis, and shoulder OCD can be seen on radiographs, radiographs are less than 30% accurate at identifying elbow dysplasia. CT is recommended for this. Disease of the nerves require CT or MRI to identify. Diseases of muscles, tendons, and ligaments require CT or musculoskeletal ultrasound by a board certified radiologist.
Many causes of forelimb lamenesses are diseases we manage rather than cure; this contributes to forelimb lameness related frustration. In Dexter’s case, we didn’t need a CT to diagnose the avulsion, but we may not have identified all lesions that contributed to the lameness by forgoing the CT scan.
Supraglenoid tubercle avulsions are most commonly seen in skeletally immature large breed dogs as the supraglenoid tubercle arises from a separate ossification center and it is the origin of the biceps brachii muscle. IF the biceps has a substantial pull on the supraglenoid tubercle before it’s strongly connected to the rest of the scapula, it’s easy for avulsion to occur.
The lameness associated with an acute supraglenoid tubercle avulsion is dramatic, but is quickly resolves. Many patients with this injury are not identified until the lameness is chronic and secondary to degenerative joint disease and a nonunion articular fracture.
For acute supraglenoid tubercle avulsions, primary repair via open reduction internal fixation is recommended. A lag screw is typically used to reattach the fragment. Prognosis is excellent. A pin and tension band can also be placed, but the approach to do this is more challenging and typically requires osteotomy of the greater tubercle and careful avoidance of the suprascapular nerve. An off weight bearing bandage or Velpeau sling is recommended for 2 weeks post-operatively.
For chronic supraglenoid tubercle avulsions like Dexter’s, fragment removal and biceps tenodesis or tenotomy is the recommended treatment. Prognosis for recovery is good to excellent.
The included images include lateral views of Dexter’s shoulders preoperatively and post tenodesis orthogonal view radiographs.
