Patellarly Angled Knee Implant Augment for Tibial Stem Alignment
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Solution Overview
Problem
Existing knee joint implants face issues with anterior displacement of the tibial element during placement, leading to misalignment with the medullary canal and mechanical axis of the tibia, necessitating adjustable stems that are often limited in adjustment capabilities, resulting in positioning errors and conflicts during implant insertion.
Innovation Solution
A knee joint implant augment with a first and second contact surface and a circumferential surface designed to align with the tibia's shape, featuring a patellarly angled section that allows for optimal attachment and alignment with the medullary canal, eliminating the need for anterior displacement and ensuring secure fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the tibial element is shifted anteriorly to ensure proper contact with the knee joint augmentation, then the contact area between the tibial element and augment is improved, but the alignment with the medullary canal and mechanical axis of the tibia deteriorates
Solution Approach 1:
The knee joint implant augment incorporates a specifically designed geometry with a non-perpendicular relationship between the first contact surface (contacting tibial element) and second contact surface (contacting tibia). This angular configuration in three-dimensional space allows the tibial element to maintain proper alignment with the medullary canal while simultaneously achieving adequate contact area with the augment, eliminating the need for anterior displacement that previously compromised alignment precision.
2Stability of the object's composition
If the augment is aligned with the shape of the cut tibia, then the fit and contact area are improved, but the tibial stem may deviate from the mechanical axis of the medullary canal
Solution Approach 1:
The augment employs an angular geometric configuration where the first contact surface is oriented at a specific angle relative to the second contact surface. This three-dimensional angular design enables the augment to conform to the cut tibia surface while simultaneously guiding the tibial stem into proper alignment with the medullary canal, resolving the conflict between fit stability and alignment precision.
Solution Approach 2:
Different surfaces of the augment are designed with different orientations and geometries: the second contact surface is shaped to match the cut tibia for optimal fit, while the first contact surface is angled to ensure proper transmission of the mechanical axis through the tibial stem to the medullary canal. This localized differentiation of surface properties allows simultaneous achievement of both fit and alignment objectives.
3Manufacturing precision
If adjustable stems are used to correct positioning errors, then the alignment accuracy is improved, but the device complexity and surgical time increase
Solution Approach 1:
The aligning function is built into the augment itself through its pre-configured angular geometry, rather than requiring post-placement adjustment of the stem. The augment's first and second contact surfaces are designed at specific angles to automatically guide the tibial stem into correct alignment with the medullary canal during a single placement action, eliminating the need for complex adjustable mechanisms and multiple surgical adjustments.
Data Source
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AI summary
Knee joint implant augment (8) which is designed to be arranged in an implanted state between a knee joint implant (1) and a tibia (2), comprising a first contact surface (14) which is designed to lie at least partially flat against the knee joint implant (1) in the implanted state, a second contact surface (16) opposite the first contact surface (14) which is designed to be able to lie at least partially flat against the tibia (2) in the implanted state, and a mantle surface (18) which connects an edge of the first contact surface (14) with an edge of the second contact surface (16).The surface (18) is designed such that a section (20) of the surface (18), which is arranged patellarly in the implanted state of the knee joint implant augment (8), is angled from the first contact surface (14) at an angle (α) greater than 0° with respect to an axis (36) in the patellar direction, wherein the axis (36) is perpendicular to the first contact surface (14).