Expandable Hip Stem for Customized Femoral Canal Fit
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Solution Overview
Problem
Existing hip arthroplasty implants face challenges in achieving a precise fit within the femoral canal, leading to potential subsidence and difficulties in revision surgeries due to variations in patient anatomy.
Innovation Solution
The development of expandable hip stems that can adjust in medial/lateral, anterior/posterior, and/or proximal/distal directions, utilizing modular systems and actuation assemblies to enhance fit and fixation, including features like expandable bodies and actuation mechanisms for radial expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fixed-size hip stems are used, then the implant can be manufactured and stored in standard sizes, but the fit within the femoral canal is imprecise leading to subsidence
Solution Approach 1:
The hip stem incorporates expandable sections that can be adjusted post-insertion to change the dimensions of the distal stem. This dynamic adjustment capability allows the implant to adapt to varying patient anatomies after the initial insertion, transforming a static implant into a dynamic one that can be customized in situ to achieve precise fit and prevent subsidence.
Solution Approach 2:
The distal stem is divided into multiple expandable sections that can be independently adjusted. This segmentation allows different portions of the stem to be expanded to different degrees, enabling precise customization of the fit within the femoral canal to match the specific anatomy of each patient.
2Adaptability or versatility
If multiple stem sizes are maintained in inventory to accommodate different patient anatomies, then adaptability is improved, but device complexity and inventory requirements increase
Solution Approach 1:
A single hip stem design with expandable capabilities can replace multiple fixed-size stems, serving multiple functions across different patient anatomies. The expandable sections allow one implant to adapt to various canal sizes and shapes, eliminating the need to maintain extensive inventories of different stem sizes while maintaining full adaptability to individual patient needs.
3Reliability
If the stem is expanded in the femoral canal, then the fit is enhanced and subsidence is reduced, but the insertion complexity increases
Solution Approach 1:
The hip stem is inserted in a collapsed or compact state through the femoral canal, and the expansion action is performed as a subsequent step after proper positioning is confirmed. This preliminary insertion of the compact implant simplifies the initial placement procedure, while the expansion is then activated to achieve the enhanced fit and subsidence resistance.
Data Source
AI summary
Expandable hip stem implants, systems, and methods of implanting a hip stem during a hip arthroplasty are provided. The implant may include a proximal body having a neck terminating at a free end, a distal stem having a proximal portion coupled to the proximal body and a distal portion, and a plurality of expandable bodies aligned around the distal stem. The plurality of expandable bodies have a collapsed configuration and an expanded configuration such that the plurality of expandable bodies expand radially outward away from one another.