Modular Bone Joint Implant with Dual Articulation Points

The implant is divided into two separate articulation points: a first articulation point for abduction-adduction movements and a second articulation point for flexion-extension movements. This segmentation allows each point to handle specific movement types, accommodating the natural shifting axis of rotation in the CMC joint and preventing subsidence and loosening that occur with single-point articulation.

The design extracts the articulation function from the trapezium bone by placing both articulation points within the metacarpal bone. The first articulation point uses a spherical component and the second uses a convex surface that articulates with a concave surface, both contained within the metacarpal. This eliminates the need for trapezium resection and preserves the viable bone stock.

The implant provides dynamic adaptability through two independent articulation points that allow the axis of rotation to shift naturally during different movements. The spherical first articulation point handles abduction-adduction while the convex-concave second articulation point handles flexion-extension, enabling the rotation axis to dynamically adjust according to the movement type without requiring complex active control mechanisms.

The implant segments the articulation function into two distinct points with specific geometries: a spherical first articulation point for abduction-adduction and a convex-concave second articulation point for flexion-extension. This segmentation provides complex joint functionality while maintaining relatively simple individual component designs that can be manufactured and assembled.