Shoulder arthroplasty for locked posterior dislocation of the shoulder.

Currently, there are no published series with mid- to long-term results on patients undergoing shoulder arthroplasty for locked posterior dislocation of the shoulder. We reviewed the results of patients who underwent shoulder arthroplasty for locked posterior dislocation of the shoulder to determine the results, the risk factors for an unsatisfactory outcome, and the rates of failure. Twelve shoulder arthroplasties were performed at our institution, between January 1, 1980, and December 31, 1997, in 12 patients who had a locked posterior dislocation of the shoulder. All 12 patients were followed up for a minimum of 5 years (mean, 9.0 years) or until the time of revision surgery. There was significant pain relief (P <.001) as well as improvement in external rotation from -13 degrees to 28 degrees (P =.001). On the basis of a modified Neer result rating system, there was 1 excellent, 6 satisfactory, and 5 unsatisfactory results. Three patients underwent revision surgery for posterior instability (two) and component loosening (one). Recurrent instability occurred in two patients in the early postoperative period. There were no cases of recurrent instability greater than 1 year from the time of surgery. The data from this study suggest that shoulder arthroplasty for locked posterior dislocation provides pain relief and improved motion. Among those with recurrent posterior instability, it usually appears in the early postoperative period.