Asymmetric Joint Arthroplasty Stem Self-Centering
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Solution Overview
Problem
Current joint arthroplasty techniques face challenges with mal-alignment of implant stems in long bones due to limited access and exposure during minimally invasive procedures, leading to complications such as implant loosening, pain, and increased risk of fractures, as well as variability in surgical outcomes depending on surgeon skill and native bone anatomy.
Innovation Solution
A novel long bone implant design with a proximal portion having a wider medial surface and a distal portion with a wider lateral surface, which self-centers within the medullary canal, reducing the risk of varus or valgus mal-alignment, and incorporating guide rails, voids, and keels to enhance stability and alignment during implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If minimally invasive surgical techniques are used with smaller incisions, then patient trauma and soft tissue disruption are reduced, but surgical access and exposure to the bone structure are limited
Solution Approach 1:
The implant stem employs asymmetric cross-sectional geometry where the medial-lateral dimension differs from the anterior-posterior dimension. The wider dimension is oriented medially to engage the medial cortical bone, providing self-alignment and stability without requiring extensive surgical exposure or soft tissue disruption.
2Ease of manufacture
If conventional implant stems with uniform cross-section are used, then manufacturing is simpler, but mal-alignment (varus/valgus) occurs due to limited surgical exposure
Solution Approach 1:
The implant stem incorporates pre-formed geometric features including asymmetric cross-section, guide rails, and keels that are manufactured into the implant itself. These features perform the alignment function that would otherwise require precise surgical technique and extensive exposure, effectively performing alignment actions before the implant is even inserted into the bone.
3Manufacturing precision
If larger surgical exposure is used to ensure proper stem alignment, then implant positioning accuracy is improved, but soft tissue disruption and surgical complexity increase
Solution Approach 1:
The implant stem is designed with self-aligning geometric features including asymmetric cross-section and guide rails that automatically orient the implant correctly within the medullary canal during insertion. The implant performs its own alignment function without requiring complex surgical techniques or extensive soft tissue exposure, thereby simplifying the surgical procedure while ensuring accurate positioning.
Data Source
AI summary
The invention relates to a prosthesis for implantation into a long bone during joint arthroplasty, particularly Total Shoulder Arthoplasty and Total Hip Arthroplasty, and a method for use of the implant.