Fig. 1From: Novel implant design of the proximal interphalangeal joint using an optimized rolling contact joint mechanismPlain radiograph images and coordinate frames for the middle and proximal phalanges. a Three-dimensional model of the proposed proximal interphalangeal joint (PIPJ) in full extension and maximal forward flexion. b Kinematic design of the proposed PIPJ implant illustrating the rolling contact surfaces and shapes of the extensor tendon routeBack to article page