Subscapularis avulsion of the lesser tuberosity in adolescents.

BACKGROUND

Lesser tuberosity avulsion fractures in adolescents occur infrequently. Perhaps because of their rarity, many cases are missed on initial physical exam, imaging studies, and even diagnostic arthroscopy, leading to delay in diagnosis. Without operative intervention, these injuries may cause significant morbidity, whereas operative fixation has predictably good results. We review 6 cases and compare them to a review of the previous published cases.

METHODS

All cases of isolated lesser tuberosity avulsions in skeletally immature patients treated by the senior author (MTB) at a pediatric referral center were included. The mean follow-up was over 4 years (range, 2 to 7 y). Operative treatment consisted of a diagnostic arthroscopy to evaluate for concomitant pathology, followed by an open reattachment of the tuberosity through an incision in line with the anterior axillary fold. A lasso technique using suture anchors and sutures to loop over and hold down the fragment is our preferred method as it decreases the risk of fracture seen with fixation using screws or sutures through drill holes in the tuberosity.

RESULTS

Even with a frequent delay in diagnosis, all patients had a predictably good outcome with an average American Shoulder and Elbow Surgeons score of 97 (range, 88 to 100) and a Western Ontario Shoulder Instability Index of 94 (range, 84 to 100). The patient history, symptoms, and physical exam findings were consistent across the published cases. The prototypical patient is a male, age 13, who sustains an abduction and extension injury during sports. Anterior shoulder pain, positive belly press, and lift-off signs are frequent findings.

CONCLUSIONS

A high index of suspicion is needed to recognize this uncommon injury. History, physical exam for subscapularis function, and magnetic resonance imaging should be diagnostic. Operative treatment with a suture anchor lasso technique leads to predictably good results.

LEVEL OF EVIDENCE

Level IV therapeutic study.