2004 Volume 31 Issue 1 Pages 36-42
The objective of study was to determine the restriction of soft tissue and articulation of rat ankle joint mobility following immobilization. Fifty male Wistar rats were divided randomly into experimental (n=25) and control (n=25) groups. In the experimental group, bilateral ankles of each rat were immobilized in full plantar flexion with a plaster cast; immobilization of the ankle joint was maintained for 1, 2, 4, 8 and 12 weeks. After each immobilization period, rats were anesthetized with pentobarbital sodium; subsequently, ROM on dorsiflexion of ankle joints was measured. Similarly, ROM on dorsiflexion of ankle joints was measured following skin incision and myotomy of transarticular triceps muscle of calf. The proportion of the ROM increase after skin incision was approximately 10% for each immobilization period; in contrast, following myotomy, ROM increase was 80.5% at 1 week, 63.8% at 2 weeks, 54.7% at 4 weeks, 35.5% at 8 weeks and 25.4% at 12 weeks after immobilization. The present investigation suggests that the limitation of ROM of joints at 1 month following immobilization may be derived from soft tissular (skin and muscle) changes and arthrogenic limitation may increase at 2-3 months after immobilization.
