The Triquetrum-Hamate joint: an anatomic and in vivo three-dimensional kinematic study

Abstract

Purpose: To obtain anatomic and kinematic information regarding the relative motion of the triquetrum-hamate (TqH) joint. Methods: In this anatomic study the contact surface constraints of the TqH joint that affect TqH motion were investigated by passively simulating TqH motion according to the kinematic data. Two fresh and 28 embalmed cadaver wrists were dissected. In the kinematic study we studied the in vivo 3-dimensional (3D) kinematics of the TqH joint during radioulnar deviation (RUD) and wrist flexion and extension motion (FEM) in 5 healthy wrists using a magnetic resonance image (MRI)-based markerless bone registration algorithm. Animations of the relative motion of the TqH joint were created and accurate estimates of the relative positions and orientations of the bones and axes of rotation of TqH motion during RUD and FEM were obtained. Results: The anatomic study revealed that the contact surface constraints of the TqH joint include primarily the oval convex surface of the hamate. In the kinematic study TqH motion was likely to be not helicoidal but rotational around an oval convex surface of the hamate. In RUD the triquetral movement was rotation in an ulnoflexion-radial extension plane of the wrist. In FEM it was rotation in an almost flexion-extension plane of the wrist. The axes of rotation of the TqH joint in all wrist motions always ran distal to the TqH joint. Conclusions: Typical motion of the TqH joint in functional range of motion is not a helicoidal motion on the saddle, but rather a rotational motion on an oval, whose axes of rotation are located on the distal side of the joint.