ORIGINAL ARTICLE R. Degeorges Æ J. Parasie Æ D. Mitton Æ N. Imbert J.-N. Goubier Æ F. Lavaste Three-dimensional rotations of human three-joint fingers: an optoelectronic measurement. Preliminary results Received: 9 February 2004 / Accepted: 29 May 2004 / Published online: 13 August 2004 Ó Springer-Verlag 2004 Abstract Longitudinal axial rotations of phalanges dur- ing flexion motions of digits have scarcely been analyzed with current anatomical or radiological methods. Recent optoelectronic systems were developed for three-dimen- sional (3D) kinematic analysis of human motion. These systems have the advantages of being non-invasive and non-irradiating. The current study was based on the VICON optoelectronic system. A validation of the pro- tocol was made among a sample of volunteers for further direct clinical applications. An experimental protocol was set up with adaptations to the requirements of finger analyses (multiple infrared markers inside small-sized capture volumes). The set-up and the protocol details are described. Kinematic studies consisted in recording the movements of the right hand of six volunteers (free from any visible pathology). Results were displayed for the joints of each three-joint finger with calculation of 3D rotations. Metacarpophalangeal (MCP), proximal in- terphalangeal (PIP) and distal interphalangeal (DIP) flexion angles ranged from 78° to 118°, 72° to 119° and 9° to 66° respectively. Lateral angles ranged from 5° to 39° (MCP), 4° to 39° (PIP) and 4° to 30° (DIP). Mean longitudinal axial rotations of MCP, PIP and DIP joints ranged from 11° pronation to 26° supination. The index finger was in a global pronation position (five of the six specimens). The fourth and fifth fingers were in a global supination position in every case. The third finger was in a more variable global rotation (pronation in four of the six specimens). An experimental protocol using an optoelectronic system (VICON) has been developed for a kinematic analysis of three-joint finger. A global measure study should be initiated among a wider sample of adults. A database should be created with direct clinical applications. Patients’ kinematic deficits could be graded either for standard movements (flexion/extension and abduction/adduction) or for longitudinal axial rotations. Keywords Joint rotation Æ Joint kinematics Æ Human movement Æ 3D motion Æ Adult hand Introduction Non-invasive techniques have been used to record the kinematics of three-joint digits: mathematical models [2, 12], triaxial goniometers [3] or specific gloves for gonio- metric measurement [28], Isotrak systems [19], systems with video cameras [18] or ultrasound systems [16]. Optoelectronic systems [11] were initially developed for kinematic analyses of lower limbs, trunk or pelvis. Few studies have focused on wrist or hand regions [4, 5, 6, 15, 17, 25, 26, 27]. Clinical applications consisted in analyses of hand postures and kinematics. Finger abnormalities are well suited to the application of such systems. An experimental protocol was set up with adapta- tions to the requirements of three-joint finger analyses (multiple infrared markers inside small-sized capture volumes). Then kinematic studies were carried out con- sisting of capturing the hand motions of six volunteers free from any visible pathology. The aim of the current study was to quantify precisely phalangeal three- dimensional (3D) rotations during flexion. Materials and methods Optoelectronic system The VICON optoelectronic system (VIdeo CONvector; Oxford Metrix, Oxford, UK) was used for analyses. It R. Degeorges Æ J. Parasie Æ D. Mitton Æ N. Imbert J.-N. Goubier Æ F. Lavaste Laboratoire de Biome´canique, Ecole Nationale Supe´rieure des Arts et Me´tiers (ENSAM), 151, boulevard de l’hoˆpital, 75013 Paris, France R. Degeorges (&) Domaine des grands pre´s, 3, square des myosotis, 78990 Elancourt, France E-mail: renaud.degeorges@libertysurf.fr Tel.: +33-6-60779286 Fax: +33-1-40257502 Surg Radiol Anat (2005) 27: 43–50 DOI 10.1007/s00276-004-0277-4