The effect of excessive tibial torsion on the capacity of muscles to extend the hip and knee during single-limb stance
- 作者：Jennifer Hicks ; Allison Arnold ; Frank Anderson ; Michael Schwartz ; Scott Delp
- 关键词：Crouch gait ; Tibial torsion ; Cerebral palsy ; Dynamics ; Induced acceleration
- 刊名：Gait and Posture
- 出版年：2007
- 期刊代码：106_09666362
- 类别：med
- 出版时间：October 2007
- 卷：26
- 期：4
- 页码：546-552
- 文件大小：566 K
摘要
Excessive tibial torsion, a rotational deformity about the long axis of the tibia, is common in patients with cerebral palsy who walk with a crouch gait. Previous research suggests that this deformity may contribute to crouch gait by reducing the capacity of soleus to extend the knee; however, the effects of excess external torsion on the capacity of other muscles to extend the stance limb during walking are unknown. A computer model of the musculoskeletal system was developed to simulate a range of tibial torsion deformities. A dynamic analysis was then performed to determine the effect of these deformities on the capacity of lower limb muscles to extend the hip and knee at body positions corresponding to the single-limb stance phase of a normal gait cycle. Analysis of the model confirmed that excessive external torsion reduces the extension capacity of soleus. In addition, our analysis revealed that several important muscles crossing the hip and knee are also adversely affected by excessive tibial torsion. With a tibial torsion deformity of 30°, the capacities of soleus, posterior gluteus medius, and gluteus maximus to extend both the hip and knee were all reduced by over 10%. Since a tibial torsion deformity reduces the capacity of muscles to extend the hip and knee, it may be a significant contributor to crouch gait, especially when greater than 30° from normal, and thus should be considered by clinicians when making treatment decisions.