Reverse Shoulder Spacer Using Existing Glenoid Anchor Holes
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Solution Overview
Problem
Current shoulder joint replacements, particularly in cases of severe damage to the rotator cuff, proximal humerus, and/or glenoid, lack an effective temporary spacer that can be implanted without creating additional anchoring holes in the patient's glenoid, and there are no known inverse shoulder spacers to replicate the reverse shoulder joint anatomy.
Innovation Solution
A reverse shoulder spacer design featuring a glenoid component as a convex hemisphere and a humeral component with a concave ball receptacle, secured via pins into existing anchor holes in the glenoid, allowing for a temporary replacement that can be used with various reverse shoulder prostheses without additional anchoring, and a mold and kit for its production using polymethyl methacrylate bone cement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reverse shoulder spacer is designed to replicate the reverse shoulder joint anatomy with a convex hemisphere glenoid component and concave ball receptacle humeral component, then the spacer can effectively replace severe reverse shoulder prostheses, but the spacer requires additional anchoring holes in the glenoid which increases surgical complexity and compromises bone integrity
Solution Approach 1:
The spacer is designed with pre-formed pin receptacles that accept pins inserted into pre-existing anchor holes from the primary prosthesis. This preliminary preparation of the anchoring interface allows the spacer to be secured without requiring new anchoring holes to be created, thereby maintaining glenoid bone integrity while ensuring reliable spacer fixation
Solution Approach 2:
The invention introduces pins as intermediary elements that connect the spacer to the glenoid bone through the pre-existing anchor holes. These pins serve as mediators that transfer and distribute mechanical loads from the spacer to the bone, enabling secure anchoring without the need for additional invasive anchoring procedures
2Adaptability or versatility
If a custom reverse shoulder spacer is manufactured to match specific patient anatomy and prosthesis configuration, then the spacer provides optimal fit and function, but the manufacturing process becomes time-consuming and complex
Solution Approach 1:
The spacer design incorporates universal features including multiple pin receptacles that can accommodate various pin configurations and a modular structure that can adapt to different reverse shoulder prosthesis types. This universality allows a single spacer design to effectively replace multiple different prosthesis configurations, providing anatomical matching versatility without requiring custom manufacturing for each case
Solution Approach 2:
The spacer is divided into distinct functional components: a glenoid component with pin receptacles for anchoring, a humeral component with the ball receptacle, and intermediate connecting structures. This segmentation allows each component to be optimized independently for its specific function while maintaining overall adaptability, simplifying the manufacturing process by enabling standardized production of modular components
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 solution provides a versatile and secure temporary replacement for reverse shoulder joints, reducing procedural complexity and preserving bone integrity by utilizing existing anchor holes, while allowing for quick and simple fabrication during surgery.
Implementation Method 1
a polymethyl methacrylate bone cement paste is prepared by mixing the bone cement powder with the monomer liquid
Data Source
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AI summary
An inverse shoulder spacer (100) for the temporary replacement of an artificial shoulder joint, comprising a glenoid component (110) which is formed at a distal end of the glenoid component as a convex hemisphere (115), and a humeral component (120) which has a concave ball receptacle (125) at a proximal end of the humeral component for receiving the hemisphere of the glenoid component, wherein the hemisphere with the ball receptacle replicates or can replicate an inverse shoulder joint. The shoulder spacer has one or more pins (130), each of which is connected or connectable at one pin end to one of a plurality of concave pin receptacles (140) at a proximal end of the glenoid component, so that the shoulder spacer can be fixed via the pin(s) in anchor holes in a patient's glenoid.