Comparison of muscular and articular factors in the progression of contractures after spinal cord injury in rats

Abstract

Study design: Experimental, controlled trial. Objectives: To identify the relationship between the muscular and articular factors in the progression of contractures after spinal cord injury (SCI). Setting: Hiroshima University, Hiroshima, Japan. Methods: In total, 48 female Wistar rats were used. The 24 experimental rats that underwent a spinal cord transection and the other 24 control rats that underwent a sham-operation were assessed at 2, 4, 8, 12, 16, or 24 weeks postsurgery. Knee joint motion was measured for flexion and extension. Myotomy of the transarticular muscles was then performed and range of motion was measured again. The degree of contractures was assessed by goniometry measuring the femorotibial angle before and after the myotomies. Results: The spinal cord-injured rats demonstrated flaccid paralysis during the first few days postsurgery and thereafter spastic paralysis. Intra- and inter-rater reliabilities for all measurements were >0.814. Knee flexion contractures developed in the all experimental rats, and progressed for the first 12 weeks and plateaued thereafter. Both the muscular (48±5%) and articular (52±5%) factors contributed almost equally to the overall progression of the contracture. Conclusion: The present findings may shed light on the underlying pathophysiology of contractures and should help guide research towards finding the elucidation of contracture development after SCI. © 2006 International Spinal Cord Society All rights reserved.