Scapula fractures after reverse total shoulder arthroplasty: classification and treatment.

BACKGROUND: Reverse total shoulder arthroplasty (RTSA) implants have been developed to treat patients with deficient rotator cuffs. The nature of this procedure's complications and how these complications should be managed continues to evolve. Fractures of the scapula after RTSA have been described, but the incidence and best methods of treatment are unclear. QUESTIONS/PURPOSES: We therefore (1) determined the incidence and (2) developed a classification system intended to suggest the best choice of treatment. PATIENTS AND METHODS: We reviewed the records of 400 patients treated with RTSA over 4.5 years and identified all patients with scapula fractures. We identified three discrete patterns: avulsion fractures of the anterior acromion (Type I); fractures of the acromion posterior to the acromioclavicular joint (Type II); and fractures of the scapular spine (Type III).
RESULTS: Twenty-two patients (5.5%) had fractures. Eight (2.0%) had Type I fractures on the first followup radiographs; these patients were treated nonoperatively with resolution of symptoms. Ten (2.5%) had Type II fractures a mean of 10.8 months after RTSA; seven of the 10 were treated surgically with improvement in their clinical symptoms. Four (1%) had Type III fractures at a mean of 10.3 months; all four fractures were treated with surgical fixation with healing.
CONCLUSIONS: Scapula fracture is a relatively common complication of RTSA. Our observations suggest Type I fractures can be observed with a likelihood of symptom relief. For Type II fractures, we recommend acromioclavicular joint resection if stable but open reduction internal fixation if unstable. We believe Type III fractures are best treated with open reduction internal fixation. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.