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° to a mean of 138.9°. Active external rotation improved from a mean of 4.0° to a mean of 38.6°. 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

Shoulder arthroplasty in patients with a fixed anterior shoulder dislocation is fraught with difficulties and complications. Although arthroplasty reliably relieved shoulder pain in this population, limited functional results should be expected.

The purpose of this investigation was to determine whether induced micromovement could improve the consolidation of diaphyseal elongation by callus distraction. Two series of paired rabbit hindlimbs were studied. The surgical procedure, waiting period, and elongation period were identical. One hindlimb was then left under neutralization conditions, but the other limb was stimulated by axial micromovements. Reproducible tibial osteotomy and lengthening of the two tibiae were confirmed radiographically. The mineralized callus was quantified by dual-beam x-ray absorptiometry. The anteroposterior and lateral diameters of the callus were measured. A semiquantitative histologic study allowed the ratio between fibrous or cartilaginous callus or both and mineralized callus to be determined. Bones were axially compressed to failure. Callus volume, callus mineral content, callus mineral density, and mechanical forces required to failure were significantly superior on the stimulated side compared with the neutralized side, so micromovements applied after the end of elongation were beneficial for bone healing. Mechanical forces required to failure were significantly correlated to callus volume and callus mineral density.