Constrained Orthopaedic Implants With Asymmetric Articular Surfaces
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Solution Overview
Problem
Existing orthopaedic techniques struggle to effectively restore joint functionality by addressing bone defects and joint instability due to articular surface erosion or bone loss, particularly in the glenoid bone, without causing further damage or compromising joint stability.
Innovation Solution
The use of orthopaedic implants with non-spherical articular surfaces and anchor members that provide superior constraints, allowing for secure attachment and limited movement, utilizing variable radii of curvature to enhance joint stability and reduce the risk of dislocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spherical articular surfaces are used, then the implant design is simple, but joint stability is insufficient and dislocation risk increases
Solution Approach 1:
The patent applies non-spherical curvature to the articular surface, specifically using variable radii of curvature where the superior portion has a smaller radius than the inferior portion. This creates an asymmetric contoured surface that provides superior constraint and limits superior translation of the humeral implant, thereby improving joint stability while maintaining a curved surface design principle
Solution Approach 2:
The articular surface employs asymmetric geometry with different radii of curvature in the superior-inferior direction. The superior portion features a smaller radius of curvature creating a more convex profile, while the inferior portion has a larger radius, creating an asymmetric contour that provides directional constraint to prevent superior dislocation while allowing physiological motion
2Ease of operation
If the implant allows full range of motion, then joint functionality is restored, but the risk of superior movement and dislocation increases
Solution Approach 1:
The constraint mechanism is applied locally at the superior portion of the articular surface rather than uniformly across the entire surface. The superior lip with its smaller radius of curvature creates a localized constraint zone that specifically limits superior translation, while the rest of the surface maintains smooth curvature to allow physiological range of motion in other directions
3Reliability
If the articular surface is highly constrained, then dislocation is prevented, but joint mobility is reduced
Solution Approach 1:
The patent maintains a curved articular surface design with variable radii rather than flat or highly planar surfaces. This curvature allows for rolling and gliding motions that preserve joint mobility, while the specific asymmetric contour provides the necessary constraint. The surface is not overly constrained by being flat or rigid, but rather uses optimized curvature to balance mobility and stability
Data Source
AI summary
This disclosure relates to orthopaedic implants and methods for restoring functionality to a bone and/or joint. The implants disclosed herein may be dimensioned and/or positioned relative to a bone to establish a constraint. The implants may include an articular surface establishing the constraint. The articular surface may have different radii of curvature to establish a non-spherical contour.