Biomechanics of the transverse carpal arch under carpal bone loading

Xiu, Kai-Hua; Kim, Joo-Han; Li, Zong-Ming

doi:10.1016/j.clinbiomech.2010.05.011

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Volume 25, Issue 8 , Pages 776-780, October 2010

Biomechanics of the transverse carpal arch under carpal bone loading

Kai-Hua Xiu
- Hand Research Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
- School of Biological Science and Medical Engineering, Beihang University, Beijing, 100086, PR China
Joo-Han Kim
- Hand Research Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
Zong-Ming Li
- Hand Research Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio 44122, USA
- Department of Physical Medicine and Rehabilitation, Cleveland Clinic, Cleveland, Ohio 44122, USA
- Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio 44122, USA
- Corresponding author. Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH 44195, USA.

Received 18 January 2010; accepted 25 May 2010. published online 28 June 2010.

Abstract

Background

Carpal tunnel release and conservative interventions are widely used in clinical therapies of carpal tunnel syndrome. The efficacy of these treatment and interventions mainly lies in the exploitation of the mechanical properties of carpal tunnel. This study investigated the structural mechanics of the transverse carpal arch using cadaveric hands.

Methods

Paired force was applied to the insertion sites of the transverse carpal ligament at both the distal (hamate–trapezium) and proximal (pisiform–scaphoid) levels of the carpal tunnel. The two pairs of forces were simultaneously applied in an inward or outward direction when the transverse carpal ligament was intact and transected. Transverse carpal arch and carpal tunnel compliance in response to the forces were analyzed. Three-way repeated measures ANOVA were used to examine the effect of the transverse carpal ligament status (intact/transected), the level of the carpal tunnel (distal/proximal) and the force application direction (inward/outward) on the biomechanics of the transverse carpal arch.

Findings

Transverse carpal ligament plays a stabilizing role in resisting outward deformation of the carpal tunnel. The carpal tunnel at the proximal level is more flexible than the carpal tunnel at the distal level. The carpal tunnel is more compliant under the inward force application than under the outward force application.

Interpretation

The understanding of carpal tunnel mechanics potentially helps to improve the existing strategies and to develop alternatives for the treatment of carpal tunnel syndrome.

Keywords: Carpal tunnel, Transverse carpal ligament, Carpal arch, Compliance, Carpal tunnel syndrome