%0 Journal Article %T 3D Analysis of the Proximal Interphalangeal Joint Kinematics during Flexion %A Florian Hess %A Philipp F¨¹rnstahl %A Luigi-Maria Gallo %A Andreas Schweizer %J Computational and Mathematical Methods in Medicine %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/138063 %X Background. Dynamic joint motion recording combined with CT-based 3D bone and joint surface data is accepted as a helpful and precise tool to analyse joint. The purpose of this study is to demonstrate the feasibility of these techniques for quantitative motion analysis of the interphalangeal joint in 3D. Materials and Method. High resolution motion data was combined with an accurate 3D model of a cadaveric index finger. Three light-emitting diodes (LEDs) were used to record dynamic data, and a CT scan of the finger was done for 3D joint surface geometry. The data allowed performing quantitative evaluations such as finite helical axis (FHA) analysis, coordinate system optimization, and measurement of the joint distances in 3D. Results. The FHA varies by ¡ã on average. On average, the rotation in adduction/abduction and internal/external rotation were ¡ã and ¡ã, respectively. During flexion, a translational motion between 0.06£¿mm and 0.73£¿mm was observed. Conclusions. The proposed technique and methods appear to be feasible for the accurate assessment and evaluation of the PIP joint motion in 3D. The presented method may help to gain additional insights for the design of prosthetic implants, rehabilitation, and new orthotic devices. 1. Introduction The human finger joints with their intrinsic and extrinsic muscles perform differentiated and complex movements. Six muscle forces (extensor, deep and superficial flexor, lumbricalis, interosseous distalis, and proximalis) are involved in movements of the according joints. Traditional studies model the interphalangeal joints (proximal and distal) by simple hinge models [1¨C3]. However, a more current investigation [4] describes the complex incongruity of the articulating joint surfaces and the traction forces of the muscles, resulting in three-dimensional (3D) movements with several degrees of freedom. Furthermore, there is a great variance of different impacts and forces on the joint, depending on the habits of each individual. The exact knowledge of joint kinematics is the basis for developing new clinical devices such as finger joint prosthesis and orthotic tools or for improving rehabilitation of injured fingers. The impact and regulation of muscle forces and reactions on joint positions have been the subject of previous physiological studies [5¨C7]. Several techniques to reproduce and analyse the kinematic and kinetic properties of human joints have been described in the literature [8¨C10]. The results of these studies were based on interpolated data, repetitive conventional radiography, or dynamic goniometers. %U http://www.hindawi.com/journals/cmmm/2013/138063/