Thermal effects of shoulder electrothermal arthroscopic capsulorrhaphy monitored by differential scanning calorimetry—A preliminary study

The shoulder is the most frequently dislocated joint of the human body. The instability of the joint can be caused by ligamentous capsular redundancy. When non-operative management fails for this patient, quality of life is significantly impaired and surgical treatment is required to tighten the ligaments and the joint capsule. Radiofrequency (RF) energy of electrothermal arthroscopic capsulorrhaphy (ETC) represents a relatively non-invasive method to stabilize joints with excessive laxity by thermally shrinking redundant joint capsular tissue. Due to the thermal treatment of joint capsular tissue collagen fibers the capsule shrinks, so the stability of the joint rises. RF energy induces shrinkage, but also significant decline in the structural properties of the collagenous capsular tissue, which is thought to abate the final results of the treatment. The indication of the ETC treatment, the optimal device settings and shrinkage rate are still not clarified. Differential scanning calorimetric (DSC) examination is a validly efficient method for the demonstration of structural changes in biological systems. The purpose of this study was to establish the feasibility of DSC in the field of monitoring the structural alteration of the ETC treated collagenous capsular tissue. We used cadaver tissue samples to establish the thermograms of the thermal treated and the intact capsular joint tissue. Our preliminary findings show that the untreated tissue has a much cooperated transition with about T1/2 of 1.5 °C. In case of treated sample this was about 8 °C of course with two superimposed transitions. The lower melting transition stands for the heat-treated part of collagen. This proves, that in the heat-treated part, the collagen transformed into a random coil conformation with less thermal stability and suggest that DSC can be a viable method by monitoring the structural effects of ETC.