Valderrabano Victor, Hintermann Beat, Nigg Benno M, Stefanyshyn Darren, Stergiou Pro
University of Basel, Clinic of Orthopaedic Surgery, Kantonsspital, Basel, Switzerland.
Foot Ankle Int. 2003 Dec;24(12):888-96. doi: 10.1177/107110070302401203.
The purpose of this in vitro study was to determine the biomechanical characteristics of the ankle based on the movement transfer between foot and leg before and after ankle arthrodesis, and after implantation of three currently used total ankle prostheses.
A 6-df device with an axial load of 200 N and a four-camera high-speed video system were used for the measurement of the range of motion in six fresh-frozen cadaveric leg specimens. While the foot was moved through the range of dorsiflexion/plantarflexion, the resulting foot eversion/inversion and tibial rotation were recorded. Analogously, the resulting foot eversion/inversion from tibial rotation and, vice versa, the resulting tibial rotation from foot eversion/inversion were determined. The same measurements were performed for the normal ankle, the fused ankle, and after total ankle replacement by the AGILITY, HINTEGRA, and S.T.A.R. prostheses.
While in dorsiflexion/plantarflexion of the foot, ankle joint fusion increased the movement transfer to tibial rotation by a 2.4 factor and to eversion/inversion by a 18.5 factor, whereas, this movement transfer did not change for all prostheses conditions. The movement transfer between foot eversion and tibial rotation was found to decrease for all ankle prostheses, but more in the AGILITY and S.T.A.R. prosthesis than in the HINTEGRA.
The three tested ankle joint prostheses changed the movement transferred within the ankle joint complex less than ankle fusion did, especially for dorsiflexion/plantarflexion movement of the foot. The closer the design was to the normal anatomy of the ankle, the closer the transfer of movement was shown to be replicated with respect to normal joint. It is suggested that success of total ankle arthroplasty depends on how successfully designs can mimic the movement transfer of the normal ankle, while dissipating the rotational forces and maintaining the stability of the joint.
本体外研究的目的是基于踝关节融合术前、后以及植入三种目前使用的全踝关节假体后足与小腿之间的运动传递，来确定踝关节的生物力学特征。
使用一台轴向载荷为200 N的6自由度装置和一个四摄像头高速视频系统，对六个新鲜冷冻尸体小腿标本的运动范围进行测量。当足部在背屈/跖屈范围内移动时，记录由此产生的足外翻/内翻以及胫骨旋转情况。类似地，确定由胫骨旋转引起的足外翻/内翻，反之，由足外翻/内翻引起的胫骨旋转。对正常踝关节、融合踝关节以及使用AGILITY、HINTEGRA和S.T.A.R.假体进行全踝关节置换后进行相同的测量。
在足部背屈/跖屈时，踝关节融合使向胫骨旋转的运动传递增加了2.4倍，向外翻/内翻的运动传递增加了18.5倍，而在所有假体情况下，这种运动传递没有变化。发现所有踝关节假体的足外翻与胫骨旋转之间的运动传递均减少，但AGILITY和S.T.A.R.假体比HINTEGRA假体减少得更多。
三种测试的踝关节假体对踝关节复合体内部运动传递的改变小于踝关节融合，特别是对于足部的背屈/跖屈运动。设计越接近踝关节的正常解剖结构，运动传递就越接近正常关节的情况。提示全踝关节置换术的成功与否取决于设计能否成功模拟正常踝关节的运动传递，同时消散旋转力并维持关节稳定性。
