Modular Knee Implant Conversion System for Hinge Stability
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Solution Overview
Problem
Current knee replacement revision surgeries, particularly converting a total stabilized (TS) implant to a hinge implant, face challenges such as extensive surgical time and bone loss due to the need for complete removal of existing components, especially when dealing with collateral ligament instability and cemented implants.
Innovation Solution
A modular TS-to-Hinge conversion system that allows for in situ conversion of a TS implant to a hinge implant without removing the TS implant from the bone, utilizing a femoral component with a partial hinge housing and modular components to maintain performance and durability, reducing bone removal and surgical time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a TS implant is completely removed and replaced with a hinge implant, then joint stability is improved, but surgical time increases and bone loss occurs
Solution Approach 1:
The implant system is divided into modular components: a base implant that remains in the bone and interchangeable constraint modules (CR, PS, TS, Hinge) that can be swapped. This segmentation allows the stable base implant to be retained while only the constraint module is changed, dramatically reducing surgical time and avoiding bone loss associated with complete removal.
Solution Approach 2:
The system provides dynamic adaptability by allowing the constraint level to be changed from CR to PS to TS to Hinge based on the patient's evolving ligamentous stability. The modular design enables the implant to adapt to changing clinical conditions without requiring complete removal and reimplantation.
2Reliability
If a TS implant is completely removed and replaced with a hinge implant, then joint stability is improved, but bone structure is damaged
Solution Approach 1:
By separating the implant into a permanent base component and a replaceable constraint module, the system allows conversion to hinge stability without removing the base implant from the bone. This preserves the bone-implant interface and avoids the bone loss and structural damage that would result from complete explantation.
Solution Approach 2:
The base implant is pre-installed and securely fixed to the bone during the initial surgery. This preliminary action creates a stable foundation that can support different constraint modules, eliminating the need for future bone preparation and preserving bone structure during constraint conversions.
3Productivity
If modular components are used for TS-to-Hinge conversion, then surgical time is reduced, but device complexity increases
Solution Approach 1:
The implant is segmented into modular components with standardized interfaces. The base implant contains mounting structures that accept different constraint modules through simple attachment mechanisms. This segmentation enables rapid conversion procedures while the standardized interfaces keep the complexity manageable through design simplification.
Solution Approach 2:
The base implant is designed with universal mounting capabilities that can accommodate multiple types of constraint modules (CR, PS, TS, Hinge). This multi-functionality reduces the need for multiple specialized implants and simplifies the overall system while enabling rapid conversion between constraint levels.
Data Source
AI summary
A joint prosthesis system includes a femoral component that has an articular side, a bone facing side, and medial and lateral condylar portions. The medial and lateral condylar portions at least partially define an intercondylar recess located therebetween and have a first concave surface extending in a mediolateral direction across the medial and lateral condylar portions. A first modular component has a second concave surface and is connectable to the femoral component such that, when the first modular component is connected to the femoral component, the first and second concave surfaces come together to form a transverse opening extending in the mediolateral direction. A first tibial assembly has a baseplate component and a head extending therefrom. The head defines an axle opening that extends therethrough. An axle is configured to be received within the transverse opening and axle opening so as to connect the tibial assembly to the femoral component.