Effect of wrist and interphalangeal thumb movement on zone T2 flexor pollicis longus tendon tension in a human cadaver model

Introduction Therapy after flexor pollicis longus (FPL) repair typically mimics finger flexor management, but this ignores anatomic and biomechanical features unique to the FPL. Purpose of the study We measured FPL tendon tension in zone T2 to identify biomechanically appropriate exercises for mobilizing the FPL. Methods Eight human cadaver hands were studied to identify motions that generated enough force to achieve FPL movement without exceeding hypothetical suture strength. Results With the carpometacarpal and metacarpophalangeal joints blocked, appropriate forces were produced for both passive interphalangeal (IP) motion with 30°wrist extension and simulated active IP flexion from 0°to 35°with the wrist in the neutral position. Discussion This work provides a biomechanical basis for safely and effectively mobilizing the zone T2 FPL tendon. Conclusion Our cadaver study suggests that it is safe and effective to perform early passive and active exercise to an isolated IP joint. Level of evidence NA.