Hui Hou-en J, Beals Timothy C, Brown Nicholas A T
Department of Bioengineering, University of Utah, Salt Lake City, UT 84108, USA.
Foot Ankle Int. 2007 Apr;28(4):441-7. doi: 10.3113/FAI.2007.0441.
Adult acquired flatfoot is a common condition that leads to significant morbidity. Along with bony procedures to operatively treat this condition, transfer of the flexor digitorum longus (FDL) tendon to the medial cuneiform or navicular is routinely performed. The goal of this tendon transfer is to increase the capacity of the FDL to invert the hindfoot and control the transverse tarsal joints. However, it is not known whether this biomechanical goal is met or whether one transfer site produces a larger mechanical advantage compared to another site. The purpose of this study was to calculate FDL muscle moment arms at the hindfoot with two clinically relevant transfer locations to quantify the change in mechanical advantage of the FDL after tendon transfer.
In seven cadaver specimens, muscle moment arms of the FDL with respect to hindfoot motion were measured using the tendon excursion method before and after the FDL was transferred to the plantar aspect of the navicular and medial cuneiform. The position and orientation of the foot and excursion of the FDL tendon were measured with an optoelectronic measurement system.
The FDL moment arm did not increase after tendon transfer to either the medial cuneiform or navicular when compared to its native site. There were significant decreases in FDL moment arm when transferred from its native site to the medial cuneiform (56% decrease, p=0.018) and navicular (46% decrease, p=0.026).
In contrast to the clinical proposition that FDL transfer to the navicular or medial cuneiform increases this muscle's mechanical advantage to invert the hindfoot, this cadaver study suggests that, to the contrary, FDL muscle moment arms decrease after tendon transfer.
成人获得性平足是一种常见疾病，会导致严重的发病率。除了通过骨手术来治疗这种疾病外，通常还会将趾长屈肌腱（FDL）转移至内侧楔骨或舟骨。这种肌腱转移的目的是增加FDL使后足内翻并控制跗横关节的能力。然而，尚不清楚这一生物力学目标是否能够实现，也不清楚一个转移部位与另一个部位相比是否能产生更大的机械优势。本研究的目的是计算FDL在两个临床相关转移位置时在后足的肌肉力臂，以量化肌腱转移后FDL机械优势的变化。
在7个尸体标本中，在将FDL转移至舟骨和内侧楔骨足底侧之前和之后，使用肌腱偏移法测量FDL相对于后足运动的肌肉力臂。使用光电测量系统测量足部的位置和方向以及FDL肌腱的偏移。
与原位相比，将FDL肌腱转移至内侧楔骨或舟骨后，其力臂并未增加。从原位转移至内侧楔骨（减少56%，p = 0.018）和舟骨（减少46%，p = 0.026）时，FDL力臂显著降低。
与FDL转移至舟骨或内侧楔骨可增加该肌肉使后足内翻的机械优势这一临床观点相反，本尸体研究表明，肌腱转移后FDL肌肉力臂反而减小。
