Shoulder Prosthesis Mounting Mechanism for Precise Humeral Positioning
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Solution Overview
Problem
Existing shoulder joint prostheses are not fully satisfactory in ensuring proper anatomical positioning of bones for optimal ligament tension and balance, and the placement of suture threads through external fins is difficult due to concealment and blind engagement.
Innovation Solution
The use of conical cavities and a conical lug with shim surfaces and facets on the humeral shaft and proximal element allows for adjustable positioning of the humeral shaft relative to the articular surface, enabling precise alignment and stabilization, along with inclined holes in the fins for easier suture thread placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing mounting means are used, then the prosthesis structure is simple, but the positioning precision of the humeral shaft relative to the articular surface is insufficient
Solution Approach 1:
The mounting means allows dynamic adjustment of the proximal element's angular position relative to the humeral shaft through the polygonal portion and shim surfaces, enabling the surgeon to select optimal positioning (e.g., 0°, 45°, 90°) before final fixation with the conical lug engagement
Solution Approach 2:
The mounting interface is segmented into discrete angular positions through the polygonal portion with multiple facets, allowing stepwise adjustment rather than continuous positioning, which simplifies the adjustment mechanism while achieving precise anatomical alignment
2Ease of operation
If external fins with holes are used for suture thread engagement, then the structure is simple, but the thread placement is difficult due to concealment and blind engagement
Solution Approach 1:
The fin acts as an intermediary structure that extends laterally from the humeral shaft, providing a accessible platform for suture thread engagement. The hole in the fin serves as an intermediate access point that allows threads to be passed through without requiring blind engagement with the concealed shaft surface
Solution Approach 2:
The fin extends the engagement interface from the longitudinal axis of the shaft into the lateral dimension, creating a protruding structure that is mechanically accessible from the external side while maintaining secure attachment to the shaft
3Adaptability or versatility
If fixed positioning methods are used, then the device structure is simple, but the adaptability to different anatomical positions is limited
Solution Approach 1:
The mounting mechanism transitions from a fixed to a dynamic state during surgery, allowing angular adjustment of the proximal element relative to the humeral shaft through rotation on the conical cavity, with final locking achieved through lug engagement
Solution Approach 2:
The system allows change of the angular position parameter of the proximal element by rotating it to different orientations relative to the humeral shaft, with discrete angular positions defined by the polygonal portion facets engaging the shim surfaces
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
This solution facilitates quick and precise peroperative adjustment of the prosthetic joint, ensuring perfect positioning of the humerus in relation to the scapula, enhanced stabilization, and easier thread placement for reinserting bone fragments, thereby improving the operational effectiveness of the shoulder joint prosthesis.
Implementation Method 1
a conical lug secured to said proximal element... said lug being able to be engaged in one or the other of said conical cavities by jamming
Data Source
Figure 1~4
Figure 5~7
AI summary
This prosthesis (1) comprises a humeral shaft (6) and a proximal element (7) capable of being mounted on said humeral shaft (6) by mounting means (8-12). According to the invention, said mounting means comprise: - two conical cavities (10) formed in a proximal end surface of the humeral shaft (6), partially intersecting one another, and at least one shim surface (9) extending in the immediate vicinity of the openings of said cavities (10); - a conical lug (11) secured to said proximal element (7), the axis of which is offset in relation to a center of said proximal element (7), said lug (11) being able to be engaged in one or the other of said conical cavities (10) by jamming, and - at the base of said lug (11), a polygonal portion (12) centered on the axis of said lug, forming at least two shim facets capable of alternatingly coming, depending on the angular position of the proximal element (7) in relation to the humeral shaft (6), into the immediate vicinity of said shim surface (9) comprised by said humeral shaft (6).