Does thermotherapy improve the joint extensibility of an immobilized joint? An experimental rat study

Abstract

[Purpose] To examine the extensibility following thermotherapy of immobilized joints. [Subjects] Twelve female Wistar rats (8 weeks old) were used in this study. [Methods] The right ankle joint was immobilized in full plantar flexion using a cast for a week. The rats were divided into a thermotherapy group and a control group. The rats in the thermotherapy group were immersed in a hot bath (42°C). For both groups, the resistance force up to the joint’s end-range was measured. [Results] The median of the thermotherapy group was 2.8 N, and the median of the control group was 3.0 N. There was no significant difference between the groups. [Conclusion] The extensibility of the immobilized joints was not improved by thermotherapy. Increased collagen extensibility is not enough to increase joint extensibility.