Unconstrained shoulder arthroplasty for treatment of proximal humeral nonunions

Unconstrained shoulder arthroplasty is one of several methods for treatment of proximal humeral fracture nonunions. The goal of this study was to define the results and complications of this procedure.

From 1976 to 2007, sixty-seven patients underwent unconstrained shoulder arthroplasty for proximal humeral nonunion and were followed for more than two years. There were forty-nine women and eighteen men with a mean age of sixty-four years and a mean duration of follow-up of nine years (range, two to thirty years). The fracture type according to the Neer classification was two-part in thirty-six patients, three-part in sixteen, and four-part in fifteen. Hemiarthroplasty was performed in fifty-four patients and total shoulder arthroplasty was done in the remaining thirteen.

There were thirty-three excellent or satisfactory results according to the modified Neer rating. Tuberosity healing about the prosthesis occurred in thirty-five shoulders. The mean pain score improved from 8.3 preoperatively to 4.1 at the time of follow-up (p < 0.001). The average active shoulder elevation and external rotation improved from 46° and 26° to 104° and 50° (p < 0.001). Shoulders with anatomic or nearly anatomic healing of the tuberosities had greater active elevation at the time of final follow-up (p = 0.02). There were fourteen complications in twelve patients, with twelve reoperations including five revisions. Kaplan-Meier survivorship with revision as the end point was 97% (95% confidence interval [CI]: 94.3, 100) at one year and 93% (95% CI: 88.0, 99.2) at five, ten, and twenty years.

Shoulder arthroplasty decreases pain and improves function in patients with a proximal humeral nonunion. However, the overall results are satisfactory in less than half of the patients. Tuberosity healing is inconsistent and influences the functional outcome.