Stemless Reverse Shoulder Implant for Motion and Stability
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Solution Overview
Problem
Conventional shoulder implant systems for total or hemi shoulder arthroplasty often fail to provide an optimal range of motion and stability, particularly in cases of irreparable rotator cuff damage, due to their design that replicates the natural anatomy of the shoulder joint.
Innovation Solution
A stemless shoulder prosthesis system comprising a glenoid component, humeral component, and an articulation component, where the humeral and glenoid components are attached to the resected bone using bone cement or fasteners, and the articulation component is held in place by the deltoid and rotator cuff muscles, allowing for a customizable and modular design with porous metal and ceramic or polymer materials for enhanced integration and motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional shoulder implant systems replicate the natural anatomy of the shoulder joint, then the implant structure is simple and familiar, but the range of motion and stability are insufficient, particularly in cases of irreparable rotator cuff damage
Solution Approach 1:
The patent applies the inversion principle by reversing the conventional ball-and-socket configuration. Instead of a ball on the humerus articulating with a socket on the scapula, the design places a concave articulating surface on the humeral component and a convex surface on the scapular component. This reverse configuration allows the deltoid muscle to exert a greater lever arm on the humerus, improving range of motion and stability while accommodating irreparable rotator cuff damage.
2Ease of operation
If reverse shoulder implant systems are used to increase range of motion by moving the center of rotation, then the range of motion improves, but the implant design becomes more complex and deviates from natural anatomy
Solution Approach 1:
The patent implements reverse shoulder arthroplasty by inverting the natural ball-and-socket configuration. The humeral component features a concave articulating surface while the scapular component has a convex surface, effectively reversing the conventional arrangement. This inversion moves the center of rotation to allow the deltoid muscles to exert a greater lever arm, thereby increasing range of motion despite the increased design complexity.
3Strength
If porous metal materials are used for bone integration, then the fixation strength improves, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent employs porous metal materials for the implant components that contact bone tissue. The porous structure allows bone ingrowth into the implant, creating a strong mechanical interlock and enhancing osseointegration. This improves fixation strength and long-term stability of the implant, though it does increase manufacturing complexity compared to solid metal components.
4Object-affected harmful factors
If the articulation component is held in place by muscles rather than stems, then the bone trauma during implantation is reduced, but the stability and positioning control become more difficult
Solution Approach 1:
The patent applies the extraction principle by removing the traditional stem component that extends into the medullary canal of the humerus. Instead, the humeral component is designed to be held in place primarily by the surrounding muscles (deltoid and rotator cuff muscles). This extraction eliminates the need for extensive bone reaming and stem insertion, significantly reducing bone trauma while relying on soft tissue for positioning and stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides improved range of motion and stability by reversing the ball-and-socket configuration, utilizing porous metals for bone integration, and a customizable articulation component for enhanced fixation and reduced trauma during implantation.
Implementation Method 1
The glenoid body and the humeral body are at least partially formed from a porous metal
Data Source
AI summary
The present disclosure provides a shoulder prosthesis. The shoulder prosthesis includes a glenoid component, a humeral component, and an articulation component. The glenoid component includes a glenoid body having a proximal side and a distal side, the distal side shaped to engage with a resected portion of a glenoid cavity. The humeral component includes a humeral body having a proximal side and a distal side, the distal side shaped to engage with a resected portion of a humerus. The articulation component is positionable between the proximal side of the glenoid component and the proximal side of the humeral component, the articulation component configured to be maintained between the glenoid and humeral components, after implantation, by at least one of a deltoid muscle and a rotator cuff.