Alignable Joint Prosthesis Intraoperative Axis Alignment
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Solution Overview
Problem
Existing joint prostheses, particularly for the elbow, face challenges in maintaining proper angular alignment with the capitellum, leading to wobble and instability due to lack of precise anatomical alignment during implantation.
Innovation Solution
An alignable joint prosthesis system that uses a jig to determine the axis of rotation intraoperatively, allowing for precise adjustment and fixation of the prosthesis components, including a stem, head, and set screw, to ensure correct anatomical alignment, preventing wobble by locking the prosthesis in the desired orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If bipolar prosthesis is used to allow head swiveling, then wobble is reduced, but alignment precision deteriorates and joint stability worsens
Solution Approach 1:
The prosthesis incorporates a dynamic alignment mechanism where the head can swivel relative to the stem during implantation, allowing the surgeon to adjust the angular alignment intraoperatively. This dynamic adjustment enables precise anatomical alignment to be achieved while maintaining joint stability, resolving the contradiction between stability and precision.
Solution Approach 2:
The invention allows change in the angular alignment parameter of the prosthesis head relative to the stem. By enabling swiveling motion, the system permits adjustment of the alignment angle to achieve optimal anatomical positioning, thereby improving both stability and precision simultaneously.
2Adaptability or versatility
If modular prosthesis with adjustability is used, then adaptability improves, but alignment precision deteriorates
Solution Approach 1:
The modular prosthesis incorporates a dynamic alignment feature where the head component can swivel relative to the stem component. This dynamic capability allows the surgeon to adjust the angular alignment during implantation to achieve precise anatomical positioning, thereby maintaining both adaptability and alignment precision.
Solution Approach 2:
The invention introduces an intermediary alignment mechanism (swiveling capability) between the head and stem components. This intermediary feature serves as a bridge that allows adjustment of the alignment parameter while maintaining the modular structure, thus preserving both adaptability and precision.
3Manufacturing precision
If fixed angular alignment is used, then alignment precision improves, but adaptability deteriorates
Solution Approach 1:
Rather than using a fixed angular alignment, the invention employs a dynamic swiveling mechanism that allows the head to rotate relative to the stem during implantation. This dynamic feature enables the surgeon to achieve precise anatomical alignment while maintaining the ability to adjust the alignment angle, thus resolving the contradiction between precision and adaptability.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A prosthesis is provided for replacing a portion of a bone making up a joint. The prosthesis is adapted, intraoperatively, to optimize the anatomical alignment of the prosthesis in the joint. In particular, a jig is used to identify the axis of rotation of the joint intraoperatively and to align a portion of the prosthesis with the identified axis. The angle of the head of the prosthesis is adjusted to optimize contact with the appropriate corresponding portions of the joint, at which point the position of the head is fixed to prevent further rotation of the head relative to the remainder of the prosthesis.