Cementless Tibial Tray Support Structure for Immediate Fixation
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Solution Overview
Problem
Cementless tibial trays face challenges with low post-operative fixation and lack of immediate stability due to bone ingrowth, leading to potential implant loosening and increased knee pain.
Innovation Solution
A tibial component design featuring a tibial tray with a support member having fins, arms, and optional fixation screws or anchors that enhance rotational resistance and stability by anchoring to the bone, utilizing a unique configuration that accommodates various bone cross-sectional shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cementless tibial trays are used to avoid bone cement, then the drawbacks and side effects of bone cement are eliminated, but post-operative fixation is low and immediate stability is lacking
Solution Approach 1:
The support member is divided into multiple functional components including a stem portion with fins for initial stability, angled arms for rotational resistance, and optional fixation screws or anchors for enhanced fixation. This segmentation allows each component to address specific stabilization needs without requiring bone cement.
Solution Approach 2:
The design provides preliminary mechanical stability through the stem portion and arms before bone ingrowth occurs. The fins and arms are configured to immediately resist rotation and provide structural support, creating a stable foundation that precedes biological fixation.
2Object-affected harmful factors
If fixation depends on bone ingrowth, then bone cement is not needed, but it takes several months for ingrowth to occur creating an interim period of implant instability
Solution Approach 1:
The stem portion with fins and the angled arms provide preliminary mechanical stabilization immediately upon implantation, bridging the time gap before bone ingrowth occurs. This preliminary structural support prevents implant loosening and maintains stability during the several-month ingrowth period.
Solution Approach 2:
The design anticipates the instability period by incorporating multiple fixation features (fins, arms, and optional screws/anchors) that provide a safety margin of stability. These features act as a cushion against potential loosening or failure during the vulnerable interim period before biological fixation is complete.
3Ease of manufacture
If a simple tibial tray design is used, then manufacturing is easier, but rotational resistance and stability are insufficient
Solution Approach 1:
The support member is segmented into distinct functional elements (stem with fins, angled arms, and optional fixation features) that can be manufactured separately or as an integrated component. This segmentation allows for optimized manufacturing processes while achieving complex rotational resistance and stability functions.
Solution Approach 2:
The arms are configured at specific angles relative to each other, creating an asymmetric structure that provides superior rotational resistance. This asymmetric geometry is optimized for mechanical performance while remaining manufacturable using standard orthopedic fabrication techniques.
Data Source
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AI summary
There is provided a tibial component comprising a tibial tray having a superior side and an inferior side, and a support member connected to the inferior side of the tibial tray, the support member having a stem portion, the stem portion including one or more fins and a first arm angled relative to a second arm. In one form, the fins have a curvature that extends away from the stem portion. In another form, the first arm defines an opening sized to receive an anchor wherein the anchor is configured to penetrate a portion of bone and the opening in the first arm. Optionally, the stem portion includes a first portion having a first cross sectional area and a second portion having a second cross sectional area wherein the first cross sectional area is larger than the second cross sectional area. The fins and arms can include rail protrusions.