Cryotherapy: An effective modality for decreasing intraarticular temperature after knee arthroscopy

Cryotherapy is a modality commonly used after arthroscopic procedures. We d ivided 17 patients into two groups after routine knee arthroscopy: 12 patie nts were immediately treated with ice and 5 control patients were treated w ithout; ice for the first hour. In all patients, thermocouple probes were p laced intraarticularly into the lateral gutter of the knee. Ice was placed on the operative knees of the treatment group for 2 hours. The control grou p had no intervention for the Ist hour and then had ice applied for the 2nd hour. Temperatures were continually recorded every minute for 2 hours. The temperature in the treatment group declined significantly, by 2.2 degreesC (95% confidence interval [-3.6 degreesC, - 0.12 degreesC]) over the 1st ho ur and by 0.79 degreesC (95% CI [-1.8 degreesC, 0.18 degreesC]) over the 2n d hour (P = 0.008). The temperature in the control group increased signific antly, by 5.0 degreesC (95% CI [2.4 degreesC, 7.5 degreesC]) over the 1st h our (P = 0.006). After ice was applied, the temperature fell significantly, by 4.0 degreesC (95% CI [-8.3 degreesC, 0.26 degreesC]) P = 0.06). The dif ference between the temperature decrease in the treatment group and the inc rease in the control group at 60 minutes was 7.1 degreesC. This is the firs t rigorously con ducted study in human patients that documents a statistica lly significant decline in intraarticular knee temperature with the applica tion of ice and compression to the skin. The mechanism by which cryotherapy acts must therefore include the cooling effect on the intraarticular envir onment and synovium.