Fig. 9
The final optimized design of proposed proximal interphalangeal joint (PIPJ) implant located on the phalangeal bone. a The position at 0° (full extension) of the PIPJ. b The position at 120° flexion of the PIPJ. Notations are as follows: rp and rm, the radii of rolling contact surfaces (RCSs) in the proximal phalangeal component (PPC) and middle phalangeal component (MPC), respectively, and rpe and rme, the radii of dorsal circle in the PPC and MPC heads, respectively