Penetration of cryotherapy in treatment after shoulder arthroscopy

Fifteen patients undergoing shoulder arthroscopy had indwelling temperature probes placed in the glenohumeral and subacromial spaces. All shoulders underwent diagnostic arthroscopy and debridement of the subacromial space. Cryotherapy was delivered to the shoulder via a Cryo/Cuff (AirCast, Summit, NJ) and temperatures were monitored for 90 minutes. Ten shoulders received cryotherapy and 5 were used as controls. Before cryotherapy, temperature averaged 34 degrees C in the glenohumeral joint and 31 degrees C in the subacromial space. No significant difference was seen between the temperatures recorded in the cold therapy and control groups for either the glenohumeral or subacromial space. In all cases, the subacromial space averaged 1 degree cooler than the glenohumeral joint at the conclusions of arthroscopy. These slowly equalized to an average of 35 degrees postoperatively. The present study shows that surface-applied cryotherapy does not penetrate either the glenohumeral joint or the subacromial space. Attention must be turned elsewhere to delineate how cryotherapy works.