正常手関節における3次元力学的解析 : 剛体バネモデルを用いた理論的解析

手関節

Biomechanical analysis of normal wrist joint was performed using a three-dimensional rigid body spring model technique. Ten wrist theoretical models were created from the normal anatomical data of each of the ten cadaveric wrists. In this technique，the bones are considered to be rigid bodies interposed by series of springs simulating articular cartilage and constraining ligaments. The carpal bone displacement and the joint forces were determined under the specific load assuming a grasp position. Joint reaction forces were calculated according to the deformation of each spring element. The joint force transmission ratio (%) across the radio-ulno-carpal joint was distributed with 44% at the radio“scaphoid joint，31 % at the radio-lunate joint and 25% at the triangular fibrocartilage. The ratio through the midcarpal joint was the highest at the luno-capitate joint.The most important ligaments in tenns of load transmission were the palmar radio-lunate，th e dorsal radio-triquetral and the dorsal scapho-lunate ligaments. In the analysis of the carpal kinematics，th e carpal bones in the proximal row tended to be displaced ulnarly. Therefore，those ligaments are considered to play an important role in preventing the ulnar translation of the carpal bones. The results derived from the current theoretical analysis are consistent with other experimental values. Following appropriate validation，this model and analysis technique have the possibility of direct clinical application.