The effect of radiofrequency thermal capsulorrhaphy on glenohumeral translation, rotation, and volume

The purpose of this study is to evaluate the effects of radiofrequency (RF) thermal capsulorrhaphy on the kinematic properties of the glenohumeral joint as determined by changes in resistance to multidirectional translational forces, alteration in the range of internal and external rotation, and changes in glenohumeral joint volume. Nonablative RF thermal energy was used to contract the glenohumeral joint capsule in 6 cadaveric shoulders. Measurements of translation were made after application of a 30-N load in anterior, posterior, and inferior directions. The maximum arc of internal and external rotation after application of a 1–N-m moment was also determined for vented specimens before and after thermal capsulorrhaphy. The percent reduction in glenohumeral capsular volume was measured by use of a saline solution injection-aspiration technique. Capsular shrinkage resulted in reductions in anterior, posterior, and inferior translation. The largest percent reductions in anterior translation were seen in external rotation at 45° (48%, P < .05) and 90° (41%, P < .05) abduction. For inferior translation, the largest percent reductions were seen in internal rotation at 45° (40%, P < .05) and 90° (45%, P < .05) abduction. Reductions in posterior translation were noted in internal rotation at 45° (27%, P < .05) and 90° (26%, P < .05) abduction. Other changes in translation were observed but were not statistically significant. The maximum arc of humeral rotation was reduced by a mean of 14° at 45° abduction and 9° at 90° abduction. The mean percent reduction in capsular volume for all shoulders was 37% (range, 8%-50%). This could not be correlated with percent reductions in translation and rotation. This study demonstrated the significant effect of RF thermal capsulorrhaphy in reducing glenohumeral multidirectional translation and volume with only a small loss of rotation in cadaveric shoulders.