Modular Shoulder Implant System for Stress Shielding Prevention
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Solution Overview
Problem
Current stemmed implants for joint replacement procedures, such as shoulder arthroplasties, often fail to adequately engage the proximal humerus, leading to stress-shielding, diminished bone ingrowth, and reduced long-term bone health due to their universal or non-configurable designs, which do not account for the varying size and shape of individual patient bones.
Innovation Solution
A modular implant system comprising a stemmed first component with a mounting boss and a variety of uniquely sized and shaped second components, allowing for customizable engagement with the bone to transfer stress forces and secure soft tissue or bone fragments in anatomically accurate positions, enabling a wide range of arthroplasty procedures with improved fit and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a universal or non-configurable stemmed implant design is used, then the device complexity is reduced and ease of manufacture is improved, but the adaptability to varying bone sizes and shapes deteriorates, leading to stress-shielding and diminished bone ingrowth
Solution Approach 1:
The implant is divided into multiple modular components including a stem component, a collar component, and a humeral head component. Each component can be independently selected and configured based on patient-specific anatomy, allowing the system to adapt to varying bone sizes and shapes while maintaining manageable device complexity through standardized coupling interfaces.
Solution Approach 2:
The modular components are designed with universal coupling interfaces that allow different sized and shaped components to be assembled together. The collar component, for example, can be configured in multiple ways to engage different bone geometries, making the same basic component design applicable across a wide range of patient anatomies.
2Manufacturing precision
If a universal stemmed implant design is used, then the ease of operation is improved, but the precision of bone engagement deteriorates, causing stress-shielding and reduced bone health
Solution Approach 1:
Different components of the implant system are designed with specific geometric features tailored to engage different regions of the bone. The collar component can be configured to engage the metaphyseal region with specific geometries, while the stem engages the diaphyseal region, allowing precise localization of engagement forces to appropriate bone structures.
Solution Approach 2:
The implant system offers multiple size parameters, geometric configurations, and engagement profiles across its modular components. Surgeons can select and combine components with specific parameters matched to the patient's bone anatomy, achieving precise engagement without requiring completely custom-designed implants.
3Strength
If a non-configurable implant design is used, then the device complexity is reduced, but the ability to transfer stress forces and preserve bone health deteriorates
Solution Approach 1:
The implant system segments the stress transfer function across multiple components. The stem transfers loads along the medullary canal, the collar distributes forces to the metaphyseal bone, and the humeral head articulates with the glenoid. This segmentation allows each component to be optimized for its specific mechanical function while collectively providing superior stress distribution.
Solution Approach 2:
The modular configuration allows the implant system to dynamically adapt its mechanical properties based on the specific bone anatomy and loading conditions. By selecting components with appropriate stiffness, geometry, and engagement characteristics, the system can optimize stress transfer pathways to match the patient's unique biomechanical requirements.
Data Source
AI summary
A modular implant system can include a first component and a second component. The first component can include a stem adapted to be anchored within a medullary canal of a bone and a mounting boss defining an outer coupling surface and an inner coupling surface. The second component can include a collar defining a first coupling surface adapted to engage the outer coupling surface of the mounting boss to secure the second component to the first component.