Ankle Prostheses with Curved Bone Engagement Surfaces
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Solution Overview
Problem
Current ankle arthroplasty systems and methods often result in biomechanically inaccurate implants, are time-consuming to implant, and fail to provide sufficient bone fixation, which complicates the procedure and postoperative joint motion.
Innovation Solution
The development of ankle arthroplasty systems featuring talar and tibial prostheses with specifically designed articular and bone engagement surfaces, including keels, to enhance biomechanics and bone fixation, along with specialized cutting tools and guides for streamlined implantation, such as burrs and cutting guides with rotatable cutting elements, to prepare bone surfaces with precise anterior-posterior and medial-lateral curvatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ankle arthroplasty implants are used, then the procedure can be completed with simpler implant design, but the implants fail to provide sufficient bone fixation and result in biomechanically inaccurate postoperative motion
Solution Approach 1:
The bone engagement surfaces incorporate specific curvatures (anterior-posterior curvature and medial-lateral curvature) that mirror the natural anatomy of the talar and tibial bones. The keel component features a curved profile that engages with the prepared bone surface, providing enhanced mechanical interlocking and stable fixation while maintaining biomechanical accuracy.
Solution Approach 2:
The implant is divided into distinct functional components: an articular surface portion for joint replacement and a keel portion for bone fixation. This segmentation allows each component to be optimized independently - the articular surface for smooth joint motion and the keel for secure bone anchorage - thereby achieving both reliable fixation and biomechanical accuracy without excessive overall complexity.
2Manufacturing precision
If traditional implantation methods are used, then the surgical procedure can be performed with simpler techniques, but the procedure is time-consuming and lacks precision
Solution Approach 1:
The implant system includes pre-configured cutting guides and burrs with specific curvature radii that are designed to prepare the bone surface to the exact specifications required for the implant. This preliminary preparation ensures that when the implant is inserted, the bone surfaces are already optimally shaped, eliminating the need for time-consuming intraoperative adjustments and achieving precise biomechanical alignment from the start.
Solution Approach 2:
The cutting guides and burrs are designed to replicate the natural curvature of the talar and tibial bones. By using tools that copy the intended final shape, the surgeon can directly prepare the bone surfaces to match the implant geometry, ensuring precise fit and orientation without requiring complex measurement and calculation procedures during surgery.
3Stability of the object's composition
If implants without specific curvature profiles are used, then the implant design can be simpler, but the postoperative motion characteristics do not mimic natural ankle joint movement
Solution Approach 1:
The articular surfaces are designed with specific curvature parameters - including anterior-posterior curvature radius and medial-lateral curvature radius - that are optimized to replicate the kinematics of the natural ankle joint. These parameter changes in the geometry allow the implant to mimic natural roll-and-glide motion patterns, providing stable and physiologically accurate joint movement.
4Strength
If keels are not used in the implant design, then the implant structure can be simpler, but sufficient attachment to the underlying bone cannot be achieved
Solution Approach 1:
The keel is designed with a curved profile featuring specific anterior-posterior and medial-lateral curvatures that match the underlying bone anatomy. This curved geometry allows the keel to engage optimally with the prepared bone surface, distributing mechanical loads effectively and providing strong anchorage that prevents implant loosening while maintaining a relatively simple overall structure.
Data Source
AI summary
An ankle arthroplasty system may have a talar prosthesis and a tibial prosthesis, each of which has an articular surface and a bone engagement surface. Each bone engagement surface may have an anterior-posterior curvature and a medial-lateral curvature with a convex shape. A burr with a rotatable cutting element may be used to form a prepared surface on the talus or the tibia to receive the corresponding prosthesis. A cutting guide may be used to guide motion of the burr; the cutting guide may include a base and an arm movably coupled to the base. One of the base and the arm may have a guide surface, and the other may have a follower that slides along the guide surface to constrain motion of the burr such that the prepared surface has at least one concave curvature and one convex curvature.