Hicks Jennifer, Arnold Allison, Anderson Frank, Schwartz Michael, Delp Scott
Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
Gait Posture. 2007 Oct;26(4):546-52. doi: 10.1016/j.gaitpost.2006.12.003. Epub 2007 Jan 16.
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 degrees , 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 degrees from normal, and thus should be considered by clinicians when making treatment decisions.
胫骨过度扭转，即围绕胫骨长轴的旋转畸形，在以蹲伏步态行走的脑瘫患者中很常见。先前的研究表明，这种畸形可能通过降低比目鱼肌伸展膝关节的能力而导致蹲伏步态；然而，过度的外旋对行走过程中其他肌肉伸展支撑腿的能力的影响尚不清楚。开发了一个肌肉骨骼系统的计算机模型来模拟一系列胫骨扭转畸形。然后进行动态分析，以确定这些畸形对下肢肌肉在与正常步态周期单腿支撑相相对应的身体位置伸展髋部和膝部能力的影响。模型分析证实，过度的外旋会降低比目鱼肌的伸展能力。此外，我们的分析表明，跨越髋部和膝部的一些重要肌肉也会受到胫骨过度扭转的不利影响。当胫骨扭转畸形为30度时，比目鱼肌、臀中肌后部和臀大肌伸展髋部和膝部的能力均降低了10%以上。由于胫骨扭转畸形会降低肌肉伸展髋部和膝部的能力，它可能是蹲伏步态的一个重要促成因素，尤其是当与正常情况相差超过30度时，因此临床医生在做出治疗决策时应予以考虑。
