Saito Susumu, Suzuki Yoshihisa
Department of Plastic and Reconstructive Surgery, Tazukekofukai Kitano Hospital, Osaka, Japan.
J Hand Surg Am. 2011 Feb;36(2):265-71. doi: 10.1016/j.jhsa.2010.10.034.
To study the biomechanics of the volar plate of the proximal interphalangeal (PIP) joint using ultrasonography.
The subjects were 20 normal and 5 pathological digits. We included as normal subjects 20 digits (10 index and 10 middle fingers) of 10 hands of 10 volunteers who had no history of trauma or any other hand-related pathological conditions. To clarify the biomechanical effect of the A3 pulley for the volar plate motion, we included a total of 5 digits (1 index, 2 middle, and 2 ring) of 4 hands of 4 consecutive patients who had flexor tendon repair surgeries in zone II with the A3 pulley left open as pathological subjects. Transducers were applied volarly to the PIP joint and the ultrasonographic plane was kept in the central axis of the digits to display the volar plate and the flexor tendons in the same image. We recorded cine videos during active joint motion. We also obtained sequential static images for morphological analysis.
The motion of the volar plate of the normal PIP joint was as follows: when joint flexion started, the volar plate slid proximally to lie parallel to the condylar slope of the proximal phalanx. In 30° of flexion, the flexor tendons tightened and the distal portion of the volar plate moved volarward. In 45° or more of flexion, the distal portion protruded over the lip of the middle phalanx. The lip rolled dorsalward in the recess in return. In the flexor tendon repair cases, the distal portion of the volar plate did not move volarward at all, even when the joint flexed 45° or more. The main body of the volar plate showed a marked wavelike or sigmoid deformity.
To characterize the biomechanics of the volar plate of the PIP joint, we propose the following 3 sequential phases: sliding, elevating, and rolling in the recess. The A3 pulley may serve as an elevator of the volar plate, triggering the next phase of rolling in the recess. The recess can provide some articulation which the lip of the middle phalanx can roll in.
利用超声研究近端指间关节（PIP）掌板的生物力学。
受试者包括20个正常手指和5个病理手指。正常受试者为10名志愿者10只手的20个手指（10个示指和10个中指），这些志愿者无创伤史或任何其他手部相关病理状况。为阐明A3滑车对掌板运动的生物力学影响，我们纳入了4例连续患者4只手的总共5个手指（1个示指、2个中指和2个环指），这些患者在II区进行了屈肌腱修复手术，术中A3滑车保持开放作为病理受试者。将超声探头掌侧置于PIP关节处，超声平面保持在手指的中心轴上，以便在同一图像中显示掌板和屈肌腱。在关节主动运动期间记录动态视频。我们还获取了连续的静态图像用于形态学分析。
正常PIP关节掌板的运动如下：当关节开始屈曲时，掌板向近端滑动，与近端指骨的髁状斜面平行。在屈曲30°时，屈肌腱收紧，掌板远端向掌侧移动。在屈曲45°或更大角度时，掌板远端突出于中节指骨的唇缘上方。唇缘则在凹陷处向背侧滚动。在屈肌腱修复病例中，即使关节屈曲45°或更大角度，掌板远端也根本不向掌侧移动。掌板主体呈现明显的波浪状或S形畸形。
为描述PIP关节掌板的生物力学特征，我们提出以下三个连续阶段：滑动、抬高和在凹陷处滚动。A3滑车可能作为掌板的提升器，触发在凹陷处滚动的下一阶段。凹陷可提供一些关节活动，使中节指骨的唇缘能够在其中滚动。
