Hot and cold whirlpool treatments and knee joint laxity.

OBJECTIVE To examine the influence of clinical applications of heat and cold on arthrometric laxity measurements of the knee. DESIGN AND SETTING The knee joint was submersed 4 inches above the patella in hot and cold whirlpools containing water of 40 degrees C and 15 degrees C for 20 minutes. A control was also performed to provide a neutral temperature comparison group. SUBJECTS Eight males and 7 females with no history of knee injury. MEASUREMENTS The knee was maintained at 20 degrees flexion and tibial rotation at either 15 degrees of internal rotation, 15 degrees of external rotation, or a neutral measurement with a modified KT-1000 knee arthrometer equipped with an LCCB-50 strain gauge that allowed for the digital display of the applied distraction forces. Order of testing was counterbalanced. Subjects underwent each condition once, with each trial on separate days. Two 2-factor repeated measure analyses of variance were performed to test effects of temperature on knee laxity for the dependent measure (laxity at 89N and at maximal displacement forces). RESULTS There was no thermal effect on displacement at 89N nor at maximal distraction (p > .05). A difference was found with respect to test position, with external rotation showing a greater displacement than internal rotation (p < .05). CONCLUSIONS There was no evidence that hot or cold whirlpool treatments alter knee laxity as assessed with the KT-1000. Rotation of the tibia does affect the magnitude of displacement of the knee. Further research is needed to determine if these findings can be applied to ACL-deficient or ACL-reconstructed knees.