Blade-like Hip Prosthesis Stem Minimizing Trochanter Trauma
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Solution Overview
Problem
Conventional straight stem hip joint prostheses are not suitable for minimally invasive surgical techniques as they require resections and detachments of tendon and muscle insertions in the greater trochanter region, leading to increased trauma and longer rehabilitation times.
Innovation Solution
A blade-like stem design with a distal straight portion and a proximal arcuate portion, where the straight portion extends from 60% to 75% of the stem's total length, minimizing interference with the trochanter and muscle/tendon insertions by maintaining constant spacing from the bone structure, allowing for gap-free seating or controlled cement placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional straight stem design is used, then secure anchoring and primary stability are achieved, but resections and detachments of tendon and muscle insertions are required in the greater trochanter region, increasing trauma and rehabilitation time
Solution Approach 1:
The stem design incorporates a curved proximal portion that follows the natural curvature of the femoral neck, allowing the stem to be inserted through the femoral canal without requiring resection of the greater trochanter or detachment of muscle insertions. The curved geometry enables the stem to engage securely with the femoral anatomy while preserving soft tissue structures.
Solution Approach 2:
The stem transitions from a conventional straight configuration to a multi-dimensional curved path that utilizes the radial and axial dimensions simultaneously. This dimensional change allows the stem to navigate the femoral anatomy more efficiently, achieving secure anchoring while avoiding interference with the greater trochanter region.
2Reliability
If a straight stem design is used, then secure anchoring is achieved, but the lateral area interferes with the greater trochanter and requires extensive resection
Solution Approach 1:
The proximal portion of the stem is designed with a curved configuration that reduces the lateral footprint in the greater trochanter region. This curvature allows the stem to maintain secure anchoring while minimizing interference with the lateral bone structures and soft tissue insertions.
Solution Approach 2:
The stem exhibits different geometric characteristics at different locations: the distal portion maintains a straight configuration for secure anchoring in the femoral canal, while the proximal portion adopts a curved configuration to navigate around the greater trochanter and minimize lateral interference.
3Productivity
If minimally invasive surgical techniques are used, then reduced trauma and faster rehabilitation are achieved, but the stem design must accommodate restricted access and reduced resection capability
Solution Approach 1:
The curved proximal portion of the stem is specifically designed to be insertable through minimal incisions without requiring extensive resection of the greater trochanter. The curvature allows the stem to be guided into position while preserving the integrity of the surrounding bone and soft tissue structures.
Solution Approach 2:
The stem is divided into distinct geometric segments: a straight distal portion for anchoring and a curved proximal portion for navigation. This segmentation allows each portion to be optimized for its specific function while maintaining overall simplicity for minimally invasive insertion.
Data Source
AI summary
A blade-like stem of a hip joint prosthesis for anchoring in the femur, including a prosthesis neck portion and a femur-anchoring portion extending therefrom and having a proximal end and a distal end, the femur-anchoring portion including a proximal arcuate portion extending from a location adjacent the proximal end and having a radius of curvature that changes in a distal-to-proximal direction, and the femur-anchoring portion further including a distal tapered portion extending from the proximal arcuate portion toward the distal end.