Biomechanics of the transverse carpal arch under carpal bone loading.
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.


RESULTS
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.


CONCLUSIONS
The understanding of carpal tunnel mechanics potentially helps to improve the existing strategies and to develop alternatives for the treatment of carpal tunnel syndrome.
Xiu
Kai-Hua
KH
Hand Research Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Kim
Joo-Han
JH
Li
Zong-Ming
ZM
D001696:Biomechanical Phenomena; D002348:Carpal Bones / Q000502:physiology*; D005260:Female; D051225:Hamate Bone / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D008023:Ligaments, Articular / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D051222:Trapezium Bone / Q000502:physiology