Resurfacing Prosthesis Positioning Device with Interlocking Pins
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Solution Overview
Problem
Current systems for positioning resurfacing prostheses face instability, rigidity, and fragility issues, often requiring multiple plates and posing challenges with small thicknesses and complex geometries, which can lead to misalignments and increased invasiveness during joint surgeries.
Innovation Solution
A device featuring a connecting body with interlocking pins and a guillotine lock mechanism, allowing for stable coupling and easy release, utilizing a single plate for positioning, impacting, and removing the prosthesis, ensuring secure and efficient placement without metal-to-metal contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional coupling systems (toothed plates, wiring systems, suction systems) are used to position the acetabular cup, then the prosthesis can be temporarily held, but the connection becomes unstable or excessively rigid or fragile during impaction
Solution Approach 1:
The coupling system is segmented into distinct functional elements: an impaction plate with multiple pin insertion holes, separate pins with heads and shafts, and a releasing mechanism. This segmentation allows each component to perform its specific function optimally while reducing overall system complexity and improving reliability during impaction and release operations.
Solution Approach 2:
Pins serve as intermediary elements between the impaction plate and the acetabular cup. These pins transmit forces during impaction while allowing controlled release, mediating the interaction between the positioning device and the prosthesis to achieve both stable connection and easy release without excessive rigidity or fragility.
2Adaptability or versatility
If multiple different plates are used for positioning and impacting the prosthesis, then specific functions can be optimized, but the device complexity and number of components increases
Solution Approach 1:
The impaction plate is designed as a universal, multi-functional device that can perform both positioning and impacting operations. The plate includes multiple pin insertion holes arranged in different patterns and orientations, allowing it to accommodate various acetabular cup configurations and perform multiple functions with a single device, eliminating the need for separate positioning and impacting plates.
3Loss of substance
If the thickness of the acetabular cup is minimized to spare bone tissue, then bone conservation is improved, but the coupling between the cup and plate becomes more difficult and less stable
Solution Approach 1:
The coupling mechanism replaces traditional mechanical interlocking methods with a pin-based system that penetrates through the thin acetabular cup wall. The pins with expanded heads create secure anchorage points that rely on friction and geometric constraint rather than thick material, enabling stable coupling even with minimal cup thickness required for bone conservation.
4Measurement precision
If a stable and rigid connection is maintained throughout the surgical procedure, then positioning accuracy is improved, but the disengagement between plate and prosthesis becomes difficult and time-consuming
Solution Approach 1:
The coupling system transitions from a static, permanently rigid connection to a dynamic system that can change state. The pins are designed with heads that can be accessed by a releasing mechanism, allowing the connection to remain stable during impaction and positioning, then be quickly disengaged when needed. This dynamic capability maintains positioning accuracy while enabling rapid disengagement.
Solution Approach 2:
The releasing mechanism extracts or removes the pins from the acetabular cup after positioning is complete. By providing a dedicated mechanism to extract the coupling elements, the system maintains stable connection during the critical positioning phase while enabling quick and easy disengagement afterward, reducing the time required for device removal.
Data Source
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AI summary
A device for positioning a resurfacing prosthesis comprises a gripping and handling instrument (3) for a main body (2) of a resurfacing prosthesis, a connecting body (4), interposed between the gripping and handling instrument (3) and the main body (2) of the resurfacing prosthesis and adapted to connect them, coupling means (5) adapted to secure the connecting body (4) to the main body (2). The coupling means (5) comprise a plurality of bonding elements (6) adapted to be interlocked, in an irremovable manner, in respective recesses (7) provided in the connecting body (4).