THE EFFECT OF THERMAL HEATING ON THE LENGTH AND HISTOLOGIC PROPERTIESOF THE GLENOHUMERAL JOINT CAPSULE

The purpose of this study was to evaluate the effect of temperature on shrinkage and the histologic properties of glenohumeral joint capsula r tissue. Six fresh-frozen cadaveric shoulders were used for this stud y. Seven joint capsule specimens were taken from different regions fro m each glenohumeral joint and assigned to one of seven treatment group s (37 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degr ees, 80 degrees C) using a randomized block design. Specimens were pla ced in a tissue bath heated to one of the designated temperatures for 10 minutes. Specimens treated with temperatures at or above 65 degrees C experienced significant shrinkage compared with those treated with a 37 degrees C bath. The posttreatment lengths in the 70 degrees, 75 d egrees, and 80 degrees C groups were significantly less than the pretr eatment lengths. Histologic analysis revealed significant thermal alte ration characterized by hyalinization of collagen in the 65 degrees, 7 0 degrees, 75 degrees, and 80 degrees C groups. This study demonstrate d that temperatures at or above 65 degrees C caused significant shrink age of glenohumeral joint capsular tissue. These results are consisten t with histologic findings, which revealed significant thermal changes of collagen in the 65 degrees, 70 degrees, 75 degrees, and 80 degrees C groups. To verify the validity of laser application for shrinkage o f joint capsule, studies designed to compare these findings with the e ffects of laser energy must be performed.