The Effect of Thermal Heating on the Length and Histologic Properties of the Glenohumeral Joint Capsule

The purpose of this study was to evaluate the effect of temperature on shrinkage and the histologic properties of gienohumeral joint capsular tissue. Six fresh-frozen cadaveric shoulders were used for this study. Seven joint capsule specimens were taken from different re gions from each glenohumeral joint and assigned to one of seven treatment groups (37°, 55°, 60°, 65°, 70°, 75°, 80°C) using a randomized block design. Speci mens were placed in a tissue bath heated to one of the designated temperatures for 10 minutes. Specimens treated with temperatures at or above 65°C experi enced significant shrinkage compared with those treated with a 37°C bath. The posttreatment lengths in the 70°, 75°, and 80°C groups were significantly less than the pretreatment lengths. Histologic analysis re vealed significant thermal alteration characterized by hyalinization of collagen in the 65°, 70°, 75°, and 80°C groups. This study demonstrated that temperatures at or above 65°C caused significant shrinkage of gleno humeral joint capsular tissue. These results are con sistent with histologic findings, which revealed signifi cant thermal changes of collagen in the 65°, 70°, 75°, and 80°C groups. To verify the validity of laser appli cation for shrinkage of joint capsule, studies designed to compare these findings with the effects of laser energy must be performed.