Modular Hip Prosthesis Stem Segmentation for Bone Preservation
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Solution Overview
Problem
Current hip prostheses require invasive procedures due to long femoral stems, leading to bone loss and limited soft tissue preservation, with inadequate contact surface area for osteointegration and increased surgical trauma.
Innovation Solution
A modular prosthetic device comprising a separable stem and neck element made of biocompatible titanium alloys, allowing for minimal invasive surgery with adjustable dimensions and configurations to optimize bone sparing and muscle tension, facilitating better osteointegration and reduced surgical trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long femoral stems (130-190 mm) are used in hip prostheses, then the prosthesis can be securely anchored in the femur, but the surgical procedure becomes highly invasive requiring extensive excavation of the femoral canal and causing significant bone loss
Solution Approach 1:
The prosthesis is divided into modular components: a short stem (20-40 mm), a neck element, and a spherical head that can be assembled separately. This segmentation allows the stem to be kept short while maintaining anchoring stability through optimized surface area and osteointegration features, avoiding the need for long stems that require extensive femoral canal excavation
Solution Approach 2:
The invention changes the critical parameter from stem length to stem surface area. By increasing the surface area of the short stem through modular assembly and optimized geometry, the prosthesis achieves reliable anchoring without requiring the 130-190 mm stem length that causes surgical invasiveness and bone loss
2Object-affected harmful factors
If the stem size is reduced to minimize surgical invasiveness, then soft tissues can be preserved and smaller incisions can be made, but the contact surface area between bone and prosthesis decreases, compromising fixation stability
Solution Approach 1:
The prosthesis is divided into modular components: a short stem (20-40 mm), a neck element, and a spherical head that can be assembled separately. This segmentation allows the stem to be kept short while maintaining anchoring stability through optimized surface area and osteointegration features
Solution Approach 2:
The invention transitions from a single monolithic component to a modular assembly of multiple components (stem, neck element, head). This dimensional change in design architecture allows the short stem to achieve sufficient contact surface area through the combined surface area of all modular components, maintaining fixation stability while preserving soft tissues
3Reliability
If traditional long stems are used, then primary mechanical fixation can be achieved, but the available bone is not spared and subsequent implantations are prevented
Solution Approach 1:
The prosthesis is divided into modular components: a short stem (20-40 mm), a neck element, and a spherical head that can be assembled separately. This segmentation allows the stem to be kept short while maintaining anchoring stability through optimized surface area and osteintegration features
Solution Approach 2:
The invention changes the critical parameter from stem length to stem surface area. By increasing the surface area of the short stem through modular assembly and optimized geometry, the prosthesis achieves reliable anchoring without requiring the 130-190 mm stem length that causes surgical invasiveness and bone loss
Data Source
AI summary
A modular prosthetic device (1) for hip joint replacement comprising a stem (2) adapted to be inserted within the femur, a neck element (4) and a spherical head (5), the stem (2) comprising in an upper region a cavity (20) for accommodating the lower portion (40) of the neck element (4), which can be coupled in an upper region to a spherical element.