[Anatomical and biomechanical research of dorsal wrist interosseous ligaments]

To explore the anatomical features of some major dorsal wrist interosseous ligaments, and to measure their biomechanical properties to screen a suitable donor site for the repair of scapholunate dorsal ligament.

Sixteen wrist joints from 8 frozen fresh male adult cadavers were selected, whose age was 20-38 years and whose height was 165-178 cm. There were no injuries to their wrists. The follow ligaments were observed and measured for the interosseous ligaments: volar and dorsal scapholunate ligaments (SL-v, SL-d), lunotriquetral dorsal ligament (LT), trapezoid-capitate dorsal ligament (TC), capitohamate ligament (CH) and the 2nd-4th carpometacarpal ligaments (CMC-2-4). The bone-ligament-bone samples of the above ligaments were prepared for further biomechanical measurements. Ligament extension testing was performed for each bone-ligament-bone sample on a material testing system. The broken load and length were measured and statistically analyzed.

The SL and the LT were both "C" shape, attaching to the volar, proximal and dorsal joint surface. The TC and CH ligaments were mainly transverse fibers, which connected with each other at the dorsal side of capitate. The CMC-2-4 ligaments were obliquitous fibers. Within these wrist interosseous ligaments, the SL-v and CMC-4 were relatively long. The ligament length differences were significant between SL-v and TC and between CMC-4 and TC (P < 0.05). TC and CMC-2 were fairly thick. But there was no significant difference among the ligaments (P > 0.05). SL-d had the highest broken load of (73.6 +/- 9.6) N. The broken load differences were all significant between SL-d and other ligaments (P < 0.05). SL-v had largest broken length of (5.24 +/- 1.65) mm. The broken length differences were all significant between SL-v and other ligaments (P < 0.05).

The anatomical structures and biomechanical features of the wrist interosseous ligaments were closely related with their physiological functions. CMC-2 and CH are both suitable to be used for the repair of scapholunate dorsal ligament.