Knee Revision Implant Kit with Nested Offset Adapter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Revision knee replacement surgery faces challenges due to varying bone loss sizes, shapes, and locations, which complicates fixation and stability of knee revision implants, and existing metaphyseal void fillers and stem offset adapters often require more bone removal or have size limitations, making them difficult to use effectively.
Innovation Solution
A joint replacement assembly comprising a baseplate, proximal, and distal members with specific geometries and features such as grooves, protrusions, and bores that allow for adjustable alignment and fixation, enabling better accommodation of bone defects and stem offsets without requiring excessive bone removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metaphyseal void fillers and stem offset adapters are used to address bone loss and alignment issues, then fixation stability is improved, but the procedure requires more bone removal and has size restrictions
Solution Approach 1:
The stem offset adapter is placed inside the metaphyseal void filler, with the adapter's outer surface fitting within the void filler's internal geometry. This nested configuration allows both components to work together without requiring separate bone removal procedures, as the adapter utilizes the space already created by the void filler implantation.
Solution Approach 2:
The solution divides the fixation system into two separate implantable components: a metaphyseal void filler that addresses bone loss, and a stem offset adapter that provides alignment correction. This segmentation allows each component to be optimized for its specific function and implanted independently based on the patient's anatomical needs.
2Measurement precision
If a larger offset adapter is used to correct alignment, then alignment accuracy is improved, but the adapter may not fit or may risk perforating the cortical wall
Solution Approach 1:
The offset adapter features a tapered outer surface that provides different dimensional characteristics at different locations. The proximal portion has a larger diameter to accommodate greater offset requirements, while the distal portion tapers to a smaller diameter to fit within the limited space of the metaphyseal region without perforating the cortical wall.
Solution Approach 2:
The offset adapter incorporates a tapered geometry that allows it to be dynamically adapted to different anatomical configurations. The taper enables the adapter to expand into available space while maintaining structural integrity, allowing surgeons to achieve the necessary offset without being constrained by fixed-size adapters.
3Ease of operation
If the void filler is set deeper into the tibia to accommodate the offset adapter, then adapter clearance is improved, but more bone must be removed
Solution Approach 1:
The offset adapter is nested within the metaphyseal void filler, allowing the adapter to be positioned at the same depth as the void filler without requiring additional bone removal. The adapter's outer surface fits within the void filler's internal cavity, eliminating the need for deeper implantation.
4Manufacturing precision
If a smaller void filler is used to match defect size, then precision of fit is improved, but the stem diameter is limited by the void filler's internal bore
Solution Approach 1:
The system separates the void filler function from the stem support function. The void filler is sized to precisely match the bone defect for optimal fit, while the stem offset adapter provides the interface for the intramedullary stem. This allows the stem diameter to be determined by the adapter's internal bore rather than the void filler's size.
Solution Approach 2:
The stem offset adapter acts as an intermediary component between the void filler and the intramedullary stem. It transfers the load from the stem to the void filler, allowing the stem size to be independent of the void filler dimensions while maintaining structural integrity.
Data Source
AI summary
In one embodiment, the present disclosure relates to a joint replacement assembly. The joint replacement assembly comprises a baseplate having an articulating side and a bone facing side, and a proximal member having a proximal end and a distal end, the proximal end being connectable to the bone facing side of the baseplate, the distal end having a plurality of grooves arranged about a first axis extending through the proximal member in a lengthwise direction. The joint replacement assembly further comprises a distal member having a proximal end and a distal end, the proximal end being connectable to the distal end of the proximal member and having a plurality of protrusions configured to engage with the plurality of grooves and prevent rotation of the distal member about the first axis relative to the proximal member.