Hip Joint Prosthesis with Elastic Shock Absorption Layer
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Solution Overview
Problem
Conventional hip joint replacement surgeries face complications such as dislocation and loosening of the prosthesis due to abnormal strain or macrophage reaction, which are not adequately addressed by existing treatments for osteoarthritis, particularly in older patients.
Innovation Solution
A medical device with an artificial acetabulum and caput femur designed for implantation in the hip joint, featuring a fixating portion stabilized by cortical bone, with mechanical fixation elements and an elastic layer to absorb shocks, and a locking member that adjusts to strain, promoting secure fixation and reduced risk of dislocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal prosthesis is placed in Femur and a plastic bowl in Acetabulum through conventional hip joint surgery, then the hip joint can be replaced to treat osteoarthritis, but dislocation and loosening of the prosthesis occur due to abnormal strain or macrophage reactions
Solution Approach 1:
The prosthesis is divided into multiple functional components: a fixation element with cortical bone engagement features, a shock-absorbing element positioned between the fixation element and joint surface, and a joint surface element. This segmentation allows each component to address specific problems - the fixation element prevents loosening through cortical bone anchoring, the shock-absorbing element mitigates abnormal strain, and the joint surface element provides articulation.
Solution Approach 2:
A shock-absorbing element is specifically incorporated into the prosthesis structure to cushion and distribute abnormal strains before they reach the fixation elements and joint surfaces. This beforehand cushioning prevents the harmful effects of abnormal strain that would otherwise cause loosening or dislocation, directly addressing the reliability issue.
2Ease of operation
If the supporting Capsule is penetrated to access the joint during surgery, then the joint can be accessed for prosthesis implantation, but it becomes difficult to achieve full functional recovery
Solution Approach 1:
The prosthesis is designed as a segmented system with distinct fixation, shock-absorption, and articulation components that can be implanted through a minimally invasive approach. This segmentation enables access through smaller incisions while maintaining full functionality, as each component can be independently positioned and secured without requiring extensive capsule disruption.
3Ease of manufacture
If the prosthesis is fixed using conventional methods, then implantation is straightforward, but abnormal strain from patient movement or falling causes loosening and dislocation
Solution Approach 1:
The shock-absorbing element is pre-integrated into the prosthesis structure to cushion and distribute abnormal strains from patient movement or falling before they reach the fixation elements. This beforehand cushioning maintains implantation simplicity while significantly improving resistance to abnormal strain and preventing loosening or dislocation.
Solution Approach 2:
The prosthesis employs composite construction with a fixation element for anchoring, a shock-absorbing element (potentially using viscoelastic or elastomeric materials), and a joint surface element. This composite structure combines the benefits of secure fixation with strain absorption capabilities, maintaining ease of manufacture while enhancing reliability under abnormal loading conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides stable and durable fixation of the artificial hip joint, reducing the risk of dislocation and loosening, allowing for functional hip movements similar to natural joints, while promoting bone integration and comfort through elastic absorption of shocks.
Implementation Method 1
an elastic layer for shock absorption, to provide secure fixation and reduce strain on the joint
Data Source
AI summary
A medical device for implantation in a hip joint of a human patient is provided. The natural hip joint having a ball shaped caput femur as the proximal part of the femoral bone with a convex hip joint surface towards the centre of the hip joint and a bowl shaped acetabulum as part of the pelvic bone with a concave hip joint surface towards the centre of the hip joint. The caput femur has a centrally placed longitudinal extension, extending through the center of the caput and collum femur, aligned with the collum femur, defined as the caput and collum femur center axis. The medical device comprising; an artificial acetabulum, comprising a concave surface towards the centre of the hip joint. The artificial concave acetabulum is adapted to, when implanted, be fixated to the femoral bone of the human patient, and be in movable connection with an artificial caput femur fixated to the pelvic bone of the patient.