Cryotherapy: an effective modality for decreasing intraarticular temperature after knee arthroscopy. (Abstracts of Current Literature).

Martin SS, Spindler KP, Tarter JW, et al (Vanderbilt Sports Medicine Center and the Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tenn), Am J Sports Med. 2001;29:288-291.

The purpose of this study was to determine if significant decreases in knee intra-articular temperature occurred after application of cryotherapy (using a Cryo-Cuff [Models 11 A-C]) following arthroscopy for meniscal tears, osteoarthritis, loose bodies, plica, or chondromalacia.

The authors divided the subjects into a treatment group (n=12) and a control group (n=5). The same surgeon performed all procedures on an outpatient basis. Before the operation, all patients had their thigh circumferences measured 10 cm above the superior patellar pole. Following arthroscopy, an intraarticular thermocouple probe was inserted into the lateral gutter of the knees of all subjects. Moreover, 2 additional cutaneous probes were placed on the lateral and suprapatellar skin of knees. While the patient was still in the operating room, the Cryo-Cuff was placed on the knees that received surgery, but the device was not filled with ice water. While the patient was in the recovery room, oral temperatures and baseline recordings were obtained from the 3 thermocouple probes. Temperatures were recorded continuously every minute for 2 hours.

Patients in the treatment group received cryotherapy in the recovery room continuously for 2 hours immediately after arthroscopy. Cryotherapy treatment was delayed for 1 hour in the patients in the control group. These patients received treatment continuously for 1 hour thereafter. All patients were confined to bed to decrease extraneous lower limb movement. After the 2-hour observation period, the intra-articular and skin probes were removed.

Statistical analysis showed no differences in age, sex, height, weight, thigh circumference, length of time to complete the arthroscopy, surgery type, or oral temperature between the control and treatment groups. Within the treatment group, mean intra-articular temperatures decreased significantly over the first hour by 2.2 [degrees] C (95% confidence interval [CI]=-3.6 [degrees] C, -0.72 [degrees] C), and again over the second hour by 0.79 [degrees] C (95% CI=-1.8 [degrees] C, 0.18 [degrees] C); the total mean decrease in temperature over the 2 hours was 3.0 [degrees] C (95% CI=-5.0 [degrees] C, -0.94 [degrees] C). Conversely, mean intra-articular temperatures in the control group increased during the first 60 minutes by 5.0 [degrees] C (95% CI=2.4 [degrees] C, 7.5 [degrees] C). However, a significant decline in mean intra-articular temperatures was seen during the second hour after cryotherapy was started. The mean drop in temperature was 4.0 [degrees] C (95% CI=-8.3 [degrees] C, 0.26 [degrees] C), indicating that starting cryotherapy treatments 60 minutes after arthroscopy still produced a significant drop in intra-articular temperatures.

The authors reported that the effects of cryotherapy on intra-articular temperature have not been evaluated previous to this study. They stated that the results of this study confirm that the intra-articular environment, including the synovium, is cooled in response to cryotherapy and, therefore, must be included as a mechanism of action of cooling in response to trauma (eg, reduction in pain and swelling). They, however, questioned the role of compression in decreasing synovial temperature, which was not addressed in this study design.

James L Karnes, PT, PhD
D'Youville College
Buffalo, NY