Dullaert Koen, Hagen Jennifer E, Simons Paul, Gras Florian, Gueorguiev Boyko, Richards R Geoff, Klos Kajetan
AO Research Institute Davos, Davos, Switzerland.
Catholic Clinic Mainz, Department of Foot and Ankle Surgery, Mainz, Germany.
Foot Ankle Surg. 2017 Dec;23(4):250-254. doi: 10.1016/j.fas.2016.07.003. Epub 2016 Jul 20.
Collapse of the medial longitudinal arch and subluxation of the subtalar joint are common occurrences in adult flatfoot deformity. Controversy exists about the role of the tibialis posterior (TP) tendon as first and/or essential lesion. Subtle changes in the foot configuration can occur under weight bearing.
This human cadaveric study is designed to investigate the effect that isolated actuation of the TP tendon has on the medial longitudinal arch and the hindfoot configuration under simulated weight bearing.
A radiolucent frame was developed to apply axial loading on cadaveric lower legs during computer tomography (CT) examinations. Eight pairs of fresh-frozen specimens were imaged in neutral position under foot-flat loading (75N) and under single-leg stance weight bearing (700N) without and with addition of 150N pulling force on the TP tendon. Measurements of subtalar joint subluxation, forefoot arch angle and talo-first metatarsal angle were conducted on each set of CT scans.
Subtalar subluxation, talo-first metatarsal angle and talo-navicular coverage angle significantly increased under single-leg stance weight bearing, whereas forefoot arch angle significantly decreased. Actuation of the TP tendon under weight bearing did not restore the forefoot arch angle or correct subtalar subluxation and talo-metatarsal angle.
Significant effect that weight bearing has on the medial longitudinal arch and the subtalar joint configuration is demonstrated in an ex-vivo model. In absence of other medial column derangement, actuation of the TP tendon alone does not seem to reconstitute the integrity of the medial longitudinal arch or correct the hindfoot subluxation under weight bearing.
The findings of this study together with the developed model for ex-vivo investigation provide a further insight in foot anatomy.
内侧纵弓塌陷和距下关节半脱位是成人扁平足畸形的常见表现。关于胫后肌腱作为首要和/或关键病变的作用存在争议。在负重情况下足部形态会发生细微变化。
本人体尸体研究旨在探究在模拟负重情况下，单独激活胫后肌腱对内侧纵弓和后足形态的影响。
开发了一种可透射线的框架，以便在计算机断层扫描（CT）检查期间对尸体小腿施加轴向负荷。八对新鲜冷冻标本在足平负重（75N）和单腿站立负重（700N）的中立位下成像，分别在不施加和施加150N拉力于胫后肌腱的情况下进行。对每组CT扫描进行距下关节半脱位、前足弓角度和距骨 - 第一跖骨角度的测量。
在单腿站立负重时，距下半脱位、距骨 - 第一跖骨角度和距骨 - 舟骨覆盖角度显著增加，而前足弓角度显著减小。负重时激活胫后肌腱并不能恢复前足弓角度，也不能纠正距下半脱位和距骨 - 跖骨角度。
在体外模型中证实了负重对内侧纵弓和距下关节形态有显著影响。在没有其他内侧柱紊乱的情况下，仅激活胫后肌腱似乎无法在负重时重建内侧纵弓的完整性或纠正后足半脱位。
本研究结果以及所开发的体外研究模型为足部解剖学提供了进一步的见解。
