Department of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan.
Shoulder and Elbow Mechanical Research Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
J Bone Joint Surg Am. 2021 May 5;103(9):812-819. doi: 10.2106/JBJS.20.00445.
Partial avulsions of the short and/or long head of the distal biceps tendon cause pain and loss of strength. The goal of the present study was to quantify the loss of supination and flexion strength following a series of surgical releases designed to simulate partial and complete short and long head traumatic avulsions.
Mechanical testing was performed to measure supination moment arms and flexion force efficiency on 18 adult fresh-frozen specimens in pronation, neutral, and supination. The distal biceps footprint length was divided into 4 equal segments. In 9 specimens (the distal-first group), the tendon was partially cut starting distally by releasing 25%, 50%, and 75% of the insertion site. In the other 9 specimens (the proximal-first group), the releases started proximally. Mechanical testing was performed before and after each release.
Significant decreases in the supination moment arm occurred after a 75% release in the distal-first release group; the decrease was 24% in pronation (p = 0.003) and 10% in neutral (p = 0.043). No significant differences in the supination moment arm (p ≥ 0.079) or in flexion force efficiency (p ≥ 0.058) occurred in the proximal-first group.
A simulated complete short head avulsion significantly decreased the supination moment arm and therefore supination strength.
A mechanical case can be made for repair of partial distal biceps tendon avulsions when the rupture involves ≥75% of the distal insertion site.
肱二头肌短头和/或长头的部分撕脱会导致疼痛和力量丧失。本研究的目的是量化一系列旨在模拟短头和长头创伤性部分撕脱的手术松解后，旋后和屈肌力量的丧失。
在 18 个成人新鲜冷冻标本上进行力学测试，以测量旋后时的旋后力矩臂和屈肌力效率，标本处于旋前、中立和旋后位。将肱二头肌止点长度分为 4 等份。在 9 个标本（远段第一组）中，从远段开始部分切开肌腱，释放 25%、50%和 75%的插入部位。在其他 9 个标本（近段第一组）中，从近段开始松解。每次松解前后均进行力学测试。
在远段第一松解组中，75%的释放后，旋后力矩臂显著减小；在旋前位下降 24%（p=0.003），在中立位下降 10%（p=0.043）。在近段第一组中，旋后力矩臂（p≥0.079）或屈肌力效率（p≥0.058）无显著差异。
模拟的完全短头撕脱显著降低了旋后力矩臂，从而降低了旋后力量。
当断裂涉及远端插入部位的≥75%时，部分远侧肱二头肌肌腱撕脱可以进行机械修复。
