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Shoulder arthroplasty in patients with a prior anterior shoulder dislocation. Results of a multicenter study.

BACKGROUND
Prior reports of shoulder arthroplasty performed for dislocation-induced arthropathy have included only patients who had had a prior stabilizing procedure. The purpose of this study was to report the results of shoulder arthroplasty in all patients with a prior anterior shoulder dislocation, including both those previously treated operatively and those previously treated nonoperatively.


METHODS
Fifty-five shoulders undergoing arthroplasty for arthritis following a prior anterior shoulder dislocation were evaluated. Twenty-seven of the shoulders had undergone a prior anterior stabilization procedure. The measures used to evaluate the shoulders included the Constant score, adjusted Constant score, active mobility, subjective satisfaction, radiographic result, and complications.


RESULTS
The shoulders were evaluated at a mean of 45.0 months. The Constant score improved from a mean of 30.8 points preoperatively to a mean of 65.8 points at the time of follow-up. The adjusted Constant score improved from a mean of 38.2% to a mean of 79.8%. Active forward flexion improved from a mean of 82.1 degrees to a mean of 138.9 degrees. Active external rotation improved from a mean of 4.0 degrees to a mean of 38.6 degrees. Fifty patients rated the result as good or excellent. Negative prognosticators included an older age at the time of the initial dislocation and a rotator cuff tear. No significant differences in demographic factors, pre-arthroplasty function, post-arthroplasty function, pre-arthroplasty radiographic findings, post-arthroplasty radiographic findings, complication rate, or reoperation rate were noted between the patients treated with a prior operation for the anterior instability and those treated nonoperatively.


CONCLUSIONS
This investigation documented the good results obtainable with shoulder arthroplasty for the treatment of arthritis following anterior shoulder instability. In addition, our findings suggest that capsulorrhaphy-induced arthropathy may be indistinguishable from arthritis following nonoperatively treated anterior shoulder instability.