Tibial Trial Insert Spacing Adjustment Mechanism
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Solution Overview
Problem
Existing tibial trial insert systems for total knee arthroplasty often lead to incorrect adjustments of the proximal/distal spacing between the femoral and tibial components, which can result in surgical errors and compromised patient safety.
Innovation Solution
A tibial trial insert system featuring a spacing adjustment assembly with a superior connector element and an inferior base element, movably and captively coupled via a telescopic mechanism, allowing for limited proximal/distal movement and precise adjustment of the spacing using a plurality of shims.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plurality of shims are used to adjust the proximal/distal spacing between bearing component and plate component, then the spacing can be precisely adjusted, but excessive shims may be inserted leading to incorrect adjustment and surgical errors
Solution Approach 1:
The coupling arrangement transforms a static rigid connection into a dynamic limited-movement connection. The connector element and base element are movably coupled, allowing controlled movement in the proximal/distal direction while maintaining connection. This dynamic capability enables the system to accommodate spacing adjustments through shims while preventing excessive movement that would lead to incorrect positioning, thereby resolving the contradiction between adjustment precision and surgical safety.
2Stability of the object's composition
If the connector element and base element are rigidly fixed together, then structural stability is improved, but the spacing adjustment assembly becomes difficult to handle and cannot accommodate spacing variations
Solution Approach 1:
The coupling arrangement provides a dynamic solution by allowing controlled movement between the connector element and base element in the proximal/distal direction while maintaining structural connection. This movability enables easy handling and assembly of the spacing adjustment assembly, while the limited movement capability ensures structural stability is maintained during operation. The non-circular cross-sections prevent rotation, providing stability without compromising handling ease.
3Ease of operation
If the connector element and base element are freely movable relative to each other, then handling ease is improved, but uncontrolled movement leads to incorrect spacing adjustment
Solution Approach 1:
The coupling arrangement implements controlled dynamics by permitting movement in the proximal/distal direction for handling ease while constraining movement in other directions through non-circular cross-sections. This selective freedom of movement allows the assembly to be easily handled and positioned, yet prevents uncontrolled movement that would compromise spacing positioning accuracy. The end stops provide hard limits to movement, ensuring precision is maintained.
Solution Approach 2:
The coupling arrangement segments the movement freedom into different directional components. Movement is permitted in the proximal/distal direction for handling purposes, while rotation and lateral movements are constrained through non-circular cross-sections. This segmentation of movement freedom allows the system to achieve both handling ease and positioning accuracy by controlling different degrees of freedom independently.
4Adaptability or versatility
If multiple loose and/or non-pre-assembled parts are used for spacing adjustment, then adaptability is improved, but device complexity increases and handling becomes difficult
Solution Approach 1:
The coupling arrangement merges the connector element, base element, and movement control mechanisms into a single integrated assembly. This integration maintains the adaptability of spacing adjustment through shims while eliminating the complexity of multiple loose parts. The non-circular cross-sections and engagement features are built-in, providing configuration flexibility without requiring complex assembly procedures, thereby resolving the contradiction between adaptability and device complexity.
Data Source
AI summary
A tibial trial insert system has a bearing component with a superior articulating surface and an inferior surface, a plate component having a superior surface and an inferior surface, and a spacing adjustment assembly arrangeable between the bearing component and the plate component. The spacing adjustment assembly has at least one superior connector element configured to removably engage with the bearing component, and at least one inferior base element configured to removably engage with the plate component. A coupling arrangement movably couples the connector element and the base element in a proximal/distal direction to a limited extent. A plurality of shims are each slidable between the connector element and the base element to adjust a proximal/distal height of the spacing adjustment assembly to adjust a relative proximal/distal spacing between the bearing component and the plate component.