The effect of continuous cryotherapy on glenohumeral joint and subacromial space temperatures in the postoperative shoulder.

PURPOSE The objective of this investigation was to determine the effect of continuous cryotherapy on glenohumeral joint and subacromial space temperatures in the postoperative shoulder. TYPE OF STUDY Prospective, randomized, and controlled clinical trial. METHODS Twenty patients (10 cryotherapy, 10 controls) with a full-thickness rotator cuff repair were monitored with temperature sensors in the glenohumeral joint and subacromial space of the shoulder for 23 postoperative hours. Statistical analysis (P <.05) was performed using the Mann-Whitney rank-sum test. RESULTS In comparing the cryotherapy and control groups, analysis of the glenohumeral joint and subacromial space temperatures revealed a statistical significance at 4, 8, and 23, and 4, 8, 16, and 20 postoperative hours, respectively. In addition, a trend toward a temperature-rising phase occurs from 4 to 12 hours and is followed by a trend toward a thermostatic phase from 12 to 23 hours during which temperatures remain relatively constant. The subacromial space was consistently cooler than the glenohumeral joint by an interval between 0.07 degrees C to 0.50 degrees C except at 23 hours postoperative where the glenohumeral joint was 0.05 degrees C cooler. CONCLUSIONS Continuous cryotherapy causes a statistically significant reduction of both glenohumeral joint and subacromial space temperatures in the shoulder at variable times during the first 23 postoperative hours. Previous investigations have shown that minor elevations in intra-articular temperature can stimulate proteolytic enzyme activity, which has detrimental effects on articular cartilage. Previous research has also shown that cryotherapy is an effective nonpharmacological method of pain control. Yet the literature has assumed that the effects of cryotherapy are part of the basic analgesia mechanism because of a reduction in joint temperature. Our results affirm that reductions in glenohumeral joint and subacromial space temperatures in the postoperative shoulder do occur, leading to potential benefits of continuous cryotherapy as an effective mode of pain control in the postoperative care of patients.