Abstract
This study investigated the effects of loading and posture on mechanical properties of the transverse carpal ligament (TCL). Ten freshโfrozen cadaver arms were dissected to expose the TCL and positioned in the load frame of a servoโhydraulic testing machine, equipped with a load cell and custom made indenters. Four cylindrical indenters (5, 10, 20, and 35โmm) loaded the TCL in three wrist postures (30ยฐ extension, neutral and 30ยฐ flexion). Three loading cycles with a peak force of 50โN were applied at 5โN/s for each condition. The flexed wrist posture had significantly greater TCL stiffness (40.0โยฑโ3.3โN/mm) than the neutral (35.9โยฑโ3.5โN/mm, pโ=โ0.045) and extended postures (34.9โยฑโ2.8โN/mm, pโ=โ0.025). TCL stiffness using the 10 and 20โmm indenters was larger than the 5โmm indenter. Stiffness was greatest with the 20โmm indenter, which had the greatest indenter contact area on the TCL. The 35โmm indenter covered the carpal bones, compressed the carpal tunnel and produced the lowest stiffness. The complexity of the TCL makes it an important part of the carpal tunnel and the mechanical properties found are essential to understanding mechanisms of carpal tunnel syndrome.โยฉ 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1682โ1687, 2011