Velocity-dependent changes in the relative motion of the subsynovial connective tissue in the human carpal tunnel

Authors

  • Yuichi Yoshii,

    1. Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street South West, Rochester, Minnesota 55905
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  • Chunfeng Zhao,

    1. Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street South West, Rochester, Minnesota 55905
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  • Jacqueline Henderson,

    1. Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street South West, Rochester, Minnesota 55905
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  • Kristin D. Zhao,

    1. Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street South West, Rochester, Minnesota 55905
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  • Kai-Nan An,

    1. Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street South West, Rochester, Minnesota 55905
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  • Peter C. Amadio

    Corresponding author
    1. Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street South West, Rochester, Minnesota 55905
    • Orthopedic Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, 200 First Street South West, Rochester, Minnesota 55905. T: 507-538-1717; F: 507-284-5392.
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Abstract

The purpose of this study was to measure the rate-dependent changes in the relative motion of subsynovial connective tissue (SSCT) and median nerve in the human carpal tunnel. Using fluoroscopy, we measured the relative motion of middle finger flexor digitorum superficialis tendon, SSCT, and median nerve in eight human cadavers during simulated active finger flexion motions at 2.0, 5.0, 7.5, and 10.0 mm/s. The shear index was defined as the difference in motion between tendon and SSCT or tendon and nerve, expressed as a percentage of tendon excursion. The motion patterns of the SSCT and median nerve relative to tendon excursion were measured at each 10% increment (decile) of maximum tendon excursion. The tendon–SSCT shear index was significantly higher at 10.0 mm/s than at 2.0 mm/s in the single-digit motion. There were corresponding significant decreases in SSCT and median nerve motion for the 10.0 mm/s velocity compared to the 2.0 mm/s velocity. This study demonstrates that the relative motion of the tissues in the carpal tunnel appears to be dependent on tendon velocity, specifically with less nerve and SSCT motion at higher velocity tendon motion. This suggests that SSCT may be predisposed to shear injury from high-velocity tendon motion. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:62–66, 2011

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