Division of Orthopedic Surgery, University of Western Ontario, Roth-McFarlane Hand and Upper Limb Center, St Joseph's Health Care, London, Ontario, Canada; Department of Orthopedics, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
Division of Plastic and Reconstructive Surgery, University of Western Ontario, Roth-McFarlane Hand and Upper Limb Center, St Joseph's Health Care, London, Ontario, Canada.
J Hand Surg Am. 2021 Jun;46(6):485-492. doi: 10.1016/j.jhsa.2020.11.003. Epub 2020 Dec 25.
Normal digital flexion relies on flexor tendon pulleys to convert linear muscular force to angular digital motion. However, there is a growing trend to vent them partially during flexor tendon repair. The objective of this study was to examine the effects of a thermoplastic ring, acting as an external pulley, on flexor tendon biomechanics and finger range of motion (ROM) after pulley venting.
We tested 15 cadaveric digits using an in vitro active finger motion simulator. We measured loads induced by flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) as well as joint ROM with sequential sectioning of the A2, A3, and A4 pulleys compared with an intact pulley condition. At each stage, external thermoplastic pulley rings were applied snugly over the proximal and middle phalanges to recreate A2 and A4 function, respectively.
After complete venting of the A2, A3, and A4 pulleys, proximal interphalangeal joint ROM significantly decreased by 13.4° ± 2.7° and distal interphalangeal joint ROM decreased by 15.8° ± 2.1°. Application of external rings over the proximal and middle phalanx resulted in a residual ROM decrease of 8.3° ± 1.9° at the proximal interphalangeal joint and 7.9° ± 2.1° at the distal interphalangeal joint, nearly restoring ROM. Similarly, complete pulley venting resulted in reduced FDS load by 37% and FDP load by 50% compared with intact pulleys. After application of external rings, loads were restored almost to normal, with a 9% reduction for FDS load and 9% reduction for FDP load compared with intact pulleys.
The application of thermoplastic rings acting as external pulleys is an effective, noninvasive, and reproducible approach to restore flexor tendon biomechanics and digit ROM after pulley venting.
Thermoplastic rings may be a useful therapeutic adjunct in restoring joint ROM and flexor tendon loads after surgical venting of the pulleys.
正常的手指弯曲依赖于屈肌腱滑车将线性肌肉力量转化为角状手指运动。然而，现在有一种越来越流行的趋势，即在修复屈肌腱时部分切开滑车。本研究的目的是研究热塑环作为外部滑车对滑车切开后屈肌腱生物力学和手指活动范围（ROM）的影响。
我们使用体外主动手指运动模拟器测试了 15 个尸体手指。我们通过顺序切开 A2、A3 和 A4 滑车，与完整滑车条件相比，测量屈肌指浅屈肌（FDS）和屈肌指深屈肌（FDP）引起的载荷以及关节 ROM。在每个阶段，将外部热塑滑车环紧密地套在近节和中节指骨上，分别重建 A2 和 A4 的功能。
完全切开 A2、A3 和 A4 滑车后，近节指间关节 ROM 显著减少 13.4°±2.7°，远节指间关节 ROM 减少 15.8°±2.1°。在近节和中节指骨上应用外部环导致近节指间关节的残余 ROM 减少 8.3°±1.9°，远节指间关节减少 7.9°±2.1°，几乎恢复了 ROM。同样，与完整滑车相比，完全切开滑车导致 FDS 载荷减少 37%，FDP 载荷减少 50%。应用外部环后，载荷几乎恢复正常，与完整滑车相比，FDS 载荷减少 9%，FDP 载荷减少 9%。
作为外部滑车的热塑环的应用是一种有效、非侵入性和可重复的方法，可以在切开滑车后恢复屈肌腱生物力学和手指 ROM。
热塑环可能是在切开滑车后恢复关节 ROM 和屈肌腱载荷的有用治疗辅助手段。
