Reproduction of Detailed Forearm Rotation Dynamics Using Intensity- Based Biplane 2D-3D Registration Matching Method; Dynamic Analysis in Distal Radio-ulnar Joint 

Abstract

This study aimed to reproduce and analyse the in vivo dynamic rotational motion of the forearm and to clarify the forearm motion involvement and anatomical function of the triangular fibrocartilage complex (TFCC). We analysed the in vivo dynamic forearm rotational motion of the radius and the ulna, using a novel image-matching method for intensity-based biplane two-dimensional–three-dimensional (2D–3D) registration. This study included 20 upper limbs of 10 healthy volunteers. The average range of forearm rotation was 69.8 ± 14.8° for pronation and 80.8 ± 13.4° for supination. The radius was most proximal to the maximum pronation, moved distally toward the neutral position, and again proximally toward supination. The average axial translation of the radius during forearm rotation was 0.98 mm. Length changes of four virtual ligaments of TFCC, palmar and dorsal superficial radioulnar ligaments (PSL and DSL) and palmar and dorsal deep radioulnar ligaments (PDL and DDL), were investigated. We found that the PSL and DSL were most tensed in mid-rotation, PDL in pronation, and DDL in supination. The sequential tension of the four ligaments during the forearm rotation motion was found to contribute to the stability of the DRUJ over a wide range of motion. In conclusion, we describe a method for detailed evaluation of in vivo dynamic forearm motion and provide new insight on forearm kinematics and the DRUJ.