Arauz Paul, DeChello Karen, Dagum Alexander, Sisto Sue Ann, Kao Imin
Department of Mechanical Engineering, Stony Brook University, Stony Brook, NY.
School of Health Technology and Management, Stony Brook University, Stony Brook, NY.
J Hand Surg Am. 2017 Aug;42(8):658.e1-658.e7. doi: 10.1016/j.jhsa.2017.04.002. Epub 2017 May 4.
To analyze the effect of simulated proximal interphalangeal (PIP) joint arthrodesis on distal interphalangeal (DIP) joint free flexion-extension (FE) and maximal voluntary pinch forces.
Five healthy subjects were tested with the PIP joint unconstrained and constrained to selected angles to produce (1) free FE movements of the DIP joint at 2 selected angles of the metacarpophalangeal joint, and (2) maximal voluntary tip (thumb and index finger) and chuck (thumb, index, and middle fingers) pinch forces. Kinematic data from a motion analysis system, pinch force data from a mechanical pinch meter, and electromyography (EMG) data recorded from 2 flexor and extensor muscles of the index finger were collected during free FE movements of the DIP joint and pinch tests for distinct PIP joint constraint angles.
The EMG root mean square (RMS) values of the flexor digitorum profundus (FDP) and extensor digitorum (ED) did not change during free FE of the DIP joint. The extension angle of the range of motion of the DIP joint changed during free FE. It increased as the PIP constraint angle increased. The EMG RMS value of FDP and ED showed maximum values when the PIP joint was unconstrained and constrained at 0° to 20° of flexion during tip and chuck pinch. Neither the index finger metacarpophalangeal and DIP joint positions nor pinch force measurements differed with imposed PIP joint arthrodesis.
The PIP joint arthrodesis angle affects DIP joint extension. A minimal overall impact from simulated PIP arthrodesis in muscle activity and pinch force of the index finger was observed. The EMG RMS values of the FDP and ED revealed that a PIP arthrodesis at 0° to 20° of flexion leads to a more natural finger posture during tip and chuck pinch.
This study provided a quantitative comparison of free FE motion of the DIP joint, as well as FDP and ED forces during pinch, under simulated index finger PIP arthrodesis angles.
分析模拟近侧指间关节（PIP）融合对远侧指间关节（DIP）自由屈伸（FE）及最大自主捏力的影响。
对5名健康受试者进行测试，测试时PIP关节不受限制以及限制在选定角度，以产生（1）在掌指关节的2个选定角度下DIP关节的自由FE运动，以及（2）最大自主指尖（拇指和示指）和夹捏（拇指、示指和中指）捏力。在DIP关节自由FE运动以及针对不同PIP关节约束角度的捏力测试过程中，收集来自运动分析系统的运动学数据、来自机械捏力计的捏力数据以及从示指两根屈肌和伸肌记录的肌电图（EMG）数据。
在DIP关节自由FE过程中，指深屈肌（FDP）和指伸肌（ED）的EMG均方根（RMS）值未发生变化。DIP关节运动范围的伸展角度在自由FE过程中发生变化。它随着PIP约束角度的增加而增大。在指尖和夹捏过程中，当PIP关节不受限制以及屈曲0°至20°时，FDP和ED的EMG RMS值显示出最大值。施加PIP关节融合术时，示指掌指关节和DIP关节位置以及捏力测量值均无差异。
PIP关节融合角度影响DIP关节伸展。观察到模拟PIP关节融合对示指肌肉活动和捏力的总体影响最小。FDP和ED的EMG RMS值显示，在屈曲0°至20°时进行PIP关节融合会使指尖和夹捏过程中的手指姿势更自然。
本研究对模拟示指PIP关节融合角度下DIP关节的自由FE运动以及捏力过程中的FDP和ED力进行了定量比较。
