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.