Finite Element Analysis of the Wrist Arthroplasty in Rheumatoid Arthritis - Computational Biomechanics of the Wrist Joint - page 64

Fig. 6.4 Stress distribution contours for the healthy, RA and TWA model

The proximal ends of the radius and ulna were fully constrained to assist
convergence of the solution [ 21 ]. Additional constraints were occupied by fixing
the carpometacarpal joint and the insertions of tendons (abductor pollicis longus
muscle, flexor carpi radialis muscle, flexor carpi ulnaris muscle, extensor carpi
ulnaris muscle, extensor carpi radialis brevis muscle, extensor carpi radialis longus
muscle). All the components (excluding the radius and the ulna) were only allowed
to move at the z direction similar to the direction of the applied loading [ 22 ].