Histologic evaluation of the glenohumeral joint capsule after radiofrequency capsular shrinkage for atraumatic instability.

We evaluated histologically 10 biopsy specimens taken preoperatively from the anterior-inferior glenohumeral ligament from patients with atraumatic instability who had undergone radiofrequency capsular shrinkage, 10 taken immediately postoperatively, and 13 taken before revision. The synovial and subsynovial layers returned to normal histology in biopsy specimens taken from 6 months onwards. Collagen bundles in the fibrous layer continued to have a reparative histology during the period of the study (up to 37 months). The type of radiofrequency probe used (monopolar or bipolar) had no effect on the histologic healing process (P > 0.5, chi2 test). A histologic score was introduced, and this was found to have an excellent intraobserver agreement (weighted kappa, 0.840) and a moderate interobserver agreement (weighted kappa, 0.698).