The Envelope of Physiological Motion of the First Carpometacarpal Joint

Abstract

Much of the hand's functional capacity is due to the versatility of the motions at the thumb carpometacarpal (CMC) joint, which are presently incompletely defined. The aim of this study was to develop a mathematical model to completely describe the envelope of physiological motion of the thumb CMC joint and then to examine if there were differences in the kinematic envelope between women and men. In vivo kinematics of the first metacarpal with respect to the trapezium were computed from computed tomography (CT) volume images of 44 subjects (20M, 24F, 40.3 6 17.7 yr) with no signs of CMC joint pathology. Kinematics of the first metacarpal were described with respect to the trapezium using helical axis of motion (HAM) variables and then modeled with discrete Fourier analysis. Each HAM variable was fit in a cyclic domain as a function of screw axis orientation in the trapezial articular plane; the RMSE of the fits was 14.5 deg, 1.4 mm, and 0.8 mm for the elevation, location, and translation, respectively. After normalizing for the larger bone size in men, no differences in the kinematic variables between sexes could be identified. Analysis of the kinematic data also revealed notable coupling of the primary rotations of the thumb with translation and internal and external rotations. This study advances our basic understanding of thumb CMC joint function and provides a complete description of the CMC joint for incorporation into future models of hand function. From a clinical perspective, our findings provide a basis for evaluating CMC pathology, especially the mechanically mediated aspects of osteoarthritis (OA), and should be used to inform artificial joint design, where accurate replication of kinematics is essential for long-term success.

In vivo kinematics of the thumb during flexion and adduction motion: Evidence for a screw-home mechanism

“…This choice was particularly important to limit the radiation dose for the volunteers. Moreover, previous studies have shown that this methodology is a valid approach for the carpal kinematics evaluation …”

“…Finally, this study focuses on Ex–Fl and Ab–Ad of the thumb using a rig for the standardization of the movements. We specifically chose to focus on Ex–Fl and Ab–Ad because any more complex motion of the thumb (e.g., opposition, circumduction) can be defined as a combination of these two principal motions . While we acknowledge that the use of a customized rig might lead to non‐spontaneous thumb movements, the use of a rig was necessary to standardize active thumb motion and allow comparison between participants and study groups.…”

“…A custom‐designed, radiolucent, polycarbonate rig (Orthopaedic Bioengineering Laboratories, Brown University/Rhode Island Hospital, Providence, RI) was used to standardize the motion of the thumb during active Ex–Fl and Ab–Ad. The same setup and protocol was used as in scanning experiments by Crisco and colleagues . The forearm was positioned in an arm rest and held stationary.…”

Proximal‐distal shift of the center of rotation in a total wrist arthroplasty is more than twice of the healthy wrist

“…The orientation of the axis of rotation was also described using azimuth angle ( azi ) within the radial CS reference plane, and elevation angle out of the radial CS plane (Figure 4). 43 …”

Quantifying thumb opposition kinematics using dynamic computed tomography

“…Thumb kinematics have mostly been investigated using surfacebased three-dimensional (3D) motion capture techniques such as high-speed video, opto-electric, electromagnetic or computed tomography (CT)-based systems (Crisco et al, 2015b;Halilaj et al, 2015;Koff et al, 2007;Kuo et al, 2002Kuo et al, , 2004Li and Tang, 2007;Miura et al, 2004;Moojen et al, 2002;Sonenblum et al, 2004;Wolfe et al, 2000). However, none of these methods allows direct evaluation of 3D (meta)carpal bone movement.…”