Tanaka Tatsuro, Amadio Peter C, Zhao Chunfeng, Zobitz Mark E, An Kai-Nan
Biomechanics Laboratory, Department of Orthopedics, Mayo Clinic Rochester, Rochester, MN 55905, USA.
J Hand Surg Am. 2004 Sep;29(5):877-83. doi: 10.1016/j.jhsa.2004.04.014.
The purpose of this study was to investigate the effect of partial excision of the A2 pulley on the gliding resistance and the strength of the residual pulleys in a human in vitro model with or without tendon repair.
We used 32 cadaveric human fingers from 11 cadavers. The A2 pulley was excised successively 25%, 50%, and 75%, cutting either from the distal toward the proximal edge or from the proximal toward the distal edge. The peak gliding resistance between intact or repaired tendon and partially excised pulley was measured. After the gliding resistance test the pulley breaking strength and stiffness were measured.
The peak gliding resistance exhibited the same statistical trends for the intact tendon and the repaired tendon groups. In the intact tendon groups the sequential excision of the A2 pulley from the distal toward the proximal edge had no significant effect on peak gliding resistance. With the A2 pulley cut from the proximal toward the distal edge, however, there was a significant increase in peak gliding resistance with 25% remaining pulley distally (0.82 N) compared with intact (0.42 N), 75% (0.57 N), and 50% (0.63 N) pulley remaining proximally. The 25% distal portion of the A2 pulley had a significantly higher breaking strength than the 25% proximal portion (160 N vs 96.7 N, respectively). Similarly the stiffness was greater in the distal portion compared with the proximal portion (120 N/mm vs 70.5 N/mm).
After A2 pulley excision the size and location of the remaining pulley affects the resulting gliding resistance, stiffness, and failure strength. At the most extreme excision level tested the residual 25% distal segment of the pulley exhibited significantly greater peak gliding resistance compared with the 25% proximal segment, as well as greater strength and stiffness. If excision of the A2 pulley is limited to 50% (either proximally or distally), however, there is little increase in gliding resistance and the retained strength of the pulley is substantial. These data support the clinical practice of partial pulley excision, up to a limit of 50%, to facilitate exposure and tendon repair.
本研究旨在探讨在有或没有肌腱修复的人体体外模型中，A2滑车部分切除对滑动阻力及残余滑车强度的影响。
我们使用了来自11具尸体的32根尸体手指。依次切除A2滑车的25%、50%和75%，分别从远端向近端边缘或从近端向远端边缘进行切割。测量完整或修复后的肌腱与部分切除的滑车之间的峰值滑动阻力。在滑动阻力测试后，测量滑车的断裂强度和刚度。
完整肌腱组和修复肌腱组的峰值滑动阻力呈现相同的统计趋势。在完整肌腱组中，从远端向近端边缘依次切除A2滑车对峰值滑动阻力没有显著影响。然而，当从近端向远端边缘切割A2滑车时，与完整滑车（0.42 N）、近端保留75%滑车（0.57 N）和近端保留50%滑车（0.63 N）相比，远端保留25%滑车时峰值滑动阻力显著增加（0.82 N）。A2滑车的25%远端部分的断裂强度明显高于25%近端部分（分别为160 N和96.7 N）。同样，远端部分的刚度大于近端部分（120 N/mm对70.5 N/mm）。
A2滑车切除后，残余滑车的大小和位置会影响产生的滑动阻力、刚度和破坏强度。在测试的最极端切除水平下，滑车残余的25%远端部分与25%近端部分相比，表现出显著更大的峰值滑动阻力，以及更大的强度和刚度。然而，如果将A2滑车的切除限制在50%（近端或远端），滑动阻力增加很少，滑车保留的强度相当可观。这些数据支持部分滑车切除（上限为50%）的临床实践，以利于暴露和肌腱修复。
