Acromial stress fractures: correlation with acromioclavicular osteoarthritis and acromiohumeral distance.

Fractures around the acromion are a known complication of reverse total shoulder arthroplasty. The literature provides limited data on the risk factors associated with this complication as well as the ultimate outcomes after nonoperative treatment. The goal of this study was to report clinical outcomes in patients with acromial fractures after nonoperatively treated reverse total shoulder arthroplasty. The authors performed a retrospective review of 125 patients undergoing reverse total shoulder arthroplasty that included several acromial stress fractures in the postoperative period. They prospectively compared radiographic data, including acromiohumeral distance, the presence of acromioclavicular joint arthritis, clinical measures of motion, visual analog scale (VAS) pain score, American Shoulder and Elbow Surgeons (ASES) score, and Single Assessment Numeric Evaluation (SANE) score, in 2 groups based on the presence or absence of fracture in the postoperative period. Fourteen patients (11.2%) had an acromial fracture after reverse total shoulder arthroplasty at an average of 5.1 months postoperatively. Patients who had fractures had worse postoperative forward elevation before fracture (116.6 vs 143.5; P=.02) and greater pain relief after reverse shoulder replacement, before fracture (P=.04). No significant difference was found between groups when the degree of arm lengthening was compared (27.6 vs 26.2 mm), and no difference was found in the prevalence of degenerative acromioclavicular joint changes identified preoperatively (66.4% vs 77.3%). After conservative management, most patients who had an acromial fracture returned to a functional level that was comparable to that achieved before fracture.