Dillon Michael P, Barker Timothy M
Centre for Rehabilitation Science and Engineering, School of Mechanical, Manufacturing, and Medical Engineering, Queensland University of Technology, Brisbane, Queensland, Australia.
Foot Ankle Int. 2006 Feb;27(2):110-6. doi: 10.1177/107110070602700207.
Partial foot amputation may be preferred to more proximal amputation because of the perceived improvement in function associated with preserving foot length and the ankle joint complex, thus enabling normal gait and push-off. Clinically, partial foot amputees display significant wasting of the triceps surae musculature, strongly indicative of disuse. This investigation aimed to examine the belief that preserving residual foot length should be the primary operative objective necessary to maintain normal foot and ankle function.
The gait patterns of eight partial foot amputees and a cohort of matched non-amputee control subjects were analyzed using a peak three-dimensional (3D) motion analysis system incorporating an AMTI force platform (Advanced Mechanical Technology Inc., Waterton, MA). Amputee subjects used their own prostheses for the evaluation.
Amputations disarticulating the metatarsophalangeal (MTP) joint had little impact on the normal pattern of ankle power generation. However, amputation proximal to the MTP joint level resulted in virtually negligible power generation across the ankle, regardless of residual foot length. Subjects compensated for the lack of ankle power generation by adopting strategies in which the hip became the primary source of power to advance the body forward.
The primary reason for a partial foot amputation is to preserve the normal function of the foot and ankle complex associated with push-off. As such, surgery should strive to preserve the metatarsal heads to allow amputees to use the ankle's contribution to walking. Given that amputation proximal to the metatarsal heads compromised the normal propulsive function of the foot and ankle, surgery should not strive to preserve residual foot length to maintain function but should instead aim to achieve good distal tissue coverage and healing, particularly given that the hip joint(s), not the ankle, become the primary source of power for walking.
部分足部截肢可能比更近端的截肢更受青睐，因为人们认为保留足长和踝关节复合体可改善功能，从而实现正常步态和蹬离动作。临床上，部分足部截肢者的小腿三头肌明显萎缩，强烈提示废用。本研究旨在检验这样一种观点，即保留残余足长应是维持足踝正常功能的首要手术目标。
使用配备AMTI力平台（先进机械技术公司，马萨诸塞州沃特敦）的三维（3D）峰值运动分析系统，分析8名部分足部截肢者和一组匹配的非截肢对照受试者的步态模式。截肢受试者使用自己的假肢进行评估。
切断跖趾（MTP）关节的截肢对踝关节正常的发力模式影响很小。然而，在MTP关节水平近端进行截肢，无论残余足长如何，踝关节的发力几乎可以忽略不计。受试者通过采用将髋关节作为推动身体前进的主要动力来源的策略来弥补踝关节发力的不足。
部分足部截肢的主要原因是保留与蹬离相关的足踝复合体的正常功能。因此，手术应努力保留跖骨头，以使截肢者能够利用踝关节对行走的作用。鉴于跖骨头近端截肢会损害足踝的正常推进功能，手术不应为维持功能而努力保留残余足长，而应旨在实现良好的远端组织覆盖和愈合，特别是考虑到髋关节而非踝关节成为行走的主要动力来源。
