Thermal modification of joint capsular tissue has gained great popularity in the orthopedic community as a treatment method for joint instability since this new operative technique was introduced in 1994. Heating joint capsular tissue to approximately 60 to 80°C by laser or radiofrequency (RF) energy produces significant dimensional alterations (shrinkage and thickening) of the tissue treated, resulting in postoperative stabilization of the joint. Initial clinical trials in patients with shoulder instability indicated that the majority of the patients were able to return to high-level athletic performance following thermal modification of joint capsular tissue. A series of in vitro experimental studies demonstrated that the joint capsular tissue could be shortened by up to 45% through the application of laser or RF energy, although significant loss of the tissue’s mechanical properties and thermal damage of the tissue were observed with higher energy applications. In vivo experimental studies demonstrated initial deleterious effects of thermal energy application, followed by an active reparative response by cellular fibrous tissue with concomitant improvement of mechanical properties. Other studies using a different animal model showed that despite significant immediate postoperative tissue shrinkage, the tissue stretches over time if the tissue is subjected to physiological loading. Based on these scientific studies, it is proposed that thermal modification of joint capsular tissue relies not only on the initial effect (shrinkage), but to a great extent, the tissue’s biological response (repair of the thermally modified tissue with new thicker tissue) to achieve postoperative joint stability. Currently, arthroscopic thermal modification of shoulder joint capsular tissue is performed clinically at many hospitals, with generally good to excellent outcomes to date. Development and improvement of thermal energy delivery devices are actively being investigated for various clinical applications. Recently, the treatment of other joint disorders such as patellar instability have been examined. In addition, the potential for thermal modification of other musculoskeletal tissues such as cartilage is being explored. Thermal modification of musculoskeletal tissues have the potential to enhance joint stability and may become a prominent modality in the treatment of joint disorders. However, it should be emphasized that thermal treatment does cause initial deleterious effects on the tissue’s properties, and that long term results have yet to be evaluated. Carefully controlled clinical and scientific studies should further clarify the advantages and disadvantages of this technique.

Date Published: 24 January 2000
PDF: 27 pages
Proc. SPIE 10297, Matching the Energy Source to the Clinical Need: A Critical Review, 1029703 (24 January 2000); doi: 10.1117/12.375222

Published in SPIE Proceedings Vol. 10297:
Matching the Energy Source to the Clinical Need: A Critical Review
Thomas P. Ryan, Editor(s)