Cryotherapy Influences Joint Laxity and Position Sense of the Healthy Knee Joint

Objective: To investigate the influences of cryotherapy on the anteroposterior (AP) laxity and the joint position sense of the knee.

Design: Experimental.

Setting: University hospital in Japan.

Participants: Twenty healthy volunteers (10 men, 10 women; age range, 21-28y) were analyzed.

Interventions: Not applicable.

Main Outcome Measures: A cooling pad was applied to the knee for 15 minutes under the circulating medium at 4 degrees C. The subject's skin temperature over the anteromedial aspect of the knee was measured during the 15 minutes of cooling and again 15 minutes later. The accuracy of the knee joint position sense was evaluated before and after cooling by using a modified Skinner's method. AP displacement and anterior terminal stiffness (ATS) of the knee were obtained with a KT-2000 trade mark knee arthrometer.

Results: Total (AP) laxity and anterior knee laxity decreased by 1.0 and 1.2mm after 15 minutes of cooling (P=.003, P=.017), respectively. ATS and inaccuracy of position sense increased by 21N/mm and 1.7 degrees (P<.001, P=.003), respectively. All parameters had normalized at 15 minutes postcooling.

Conclusion: Cooling for 15 minutes makes the knee joint stiffer and lessens the sensitivity of the position sense. These findings may be significant and should be taken into account for therapeutic programs that involve exercise immediately after a period of cooling.