In vivo flexor tendon forces generated during rehabilitation exercises.
Lattanza-LL; Diao-E; Kursa-K; Rempel-DM
2004 Annual Meeting of the American Society for Surgery of the Hand, September 9-11, 2004, New York, New York. Rosemont, IL: American Society for Surgery of the Hand, 2004 Sep; :61
The purpose of this study is to determine the forces produced in the flexor digitorum profundus and superficialis tendons during standard flexor tendon rehabilitation protocols and the effect of wrist position on the forces generated. A scientifically based rehabilitation protocol will be developed that minimizes adhesion formation and chance of tendon rupture while maximizing tendon excursion and strength. Twelve patients undergoing open carpal tunnel release with local anesthesia volunteered to participate. They had no other upper extremity abnormalities and no systemic disease. During open CTR, buckle force transducers (Microstrain, Burlington, VT) were placed on the FDS and FDP tendons to the index finger in the carpal canal. Each patient performed the following maneuvers while being captured on video: 1. tenodesis, 2. place and hold, 3. composite active flexion/extension of the digits, 4. isolated FDS function, and 5. isolated FDP function. Data was collected and analyzed with a National Instruments A/D board in Power PC Macintosh computer. The maximum force generated in the FDS and FDP is dependent on the rehabilitation maneuver (p<.0001). The isolated FDS and FDP maneuvers generated forces in the respective tendons that were statistically significantly diff e re n t (p<.0001) than the other maneuvers. Maximum force in the FDS during the isolated maneuver was 20N and in the FDP was 73N, both neutral wrist, although the average maximum was <30N in the FDP. There was no statistically significant difference among the other maneuvers. Tenodesis, place and hold (wrist neutral) and composite active flexion (wrist neutral) generated the lowest forces (maximum force <15N with average maximum of <5 for tenodesis and place and hold and <8 for composite flexion) in both tendons. Having the wrist in 30 degrees flexion increased forces generated in the FDS, not the FDP, although it was not a statistically significant increase for any of the maneuvers. Contrary to what has been previously reported, forces are generated in the flexor tendons even during active finger extension. Based on earlier studies by Urbaniak, a tendon can withstand 21-43N of force during the first 3 weeks after repair. The results of this study show that tenodesis, place and hold, and active flexion with the wrist in neutral position fall below these force values. We recognize that postoperative swelling has not been accounted for in this study. These results support the use of tenodesis, place and hold, and active flexion under supervision during phase I rehabilitation.
Muscles; Musculoskeletal-system-disorders; Hand-injuries; Injury-prevention; Injuries; Risk-factors; Models; In-vivo-studies; Biomechanics; Repetitive-work
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
2004 Annual Meeting of the American Society for Surgery of the Hand, September 9-11, 2004, New York, New York
University of California, Richmond, California