Strain-Activated Hip Prosthesis Locking Mechanism
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Solution Overview
Problem
Current hip joint prostheses often experience complications such as dislocation and loosening due to abnormal strain, which can lead to further issues like femoral bone fracture, as they do not allow for natural movement without placing excessive stress on the fixation site.
Innovation Solution
A medical device comprising a ball-shaped piece and a bowl-shaped piece with a releasing member that changes states from a fixed to a released position when a pre-determined strain is applied, allowing for non-invasive adjustment and reduction of stress on the femoral bone, thereby reducing the risk of loosening and dislocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a completely fixed hip joint prosthesis is used to prevent dislocation, then dislocation risk is reduced, but the risk of prosthesis loosening from femoral bone fixation increases due to excessive strain on the bone
Solution Approach 1:
The hip joint prosthesis employs a dynamic locking mechanism that allows the joint to move freely during normal activity and then locks in place when abnormal movement or dislocation is detected. This dynamic behavior prevents dislocation while avoiding continuous strain on the femoral bone fixation, thereby preventing loosening.
Solution Approach 2:
The prosthesis changes its mechanical parameters (from locked to unlocked state) based on detected strain levels or positional parameters. When abnormal strain exceeds a threshold indicating potential dislocation, the mechanism transitions to a locked state, providing dislocation prevention without requiring permanent rigid fixation that would compromise bone strength.
2Stability of the object's composition
If a fixed hip joint prosthesis is used to maintain joint stability, then joint stability is improved, but the risk of femoral bone fracture increases due to excessive strain
Solution Approach 1:
The prosthesis transitions between mobile and locked states dynamically. During normal use, the joint remains mobile allowing natural movement patterns that distribute strain appropriately. When instability or abnormal strain is detected, the mechanism locks to provide stability, preventing both dislocation and excessive strain on the femoral bone that could lead to fracture.
Solution Approach 2:
The mechanism provides protective locking action before severe damage can occur. By detecting abnormal strain patterns early, the prosthesis locks preemptively to cushion the femoral bone from excessive forces that would otherwise lead to fracture, while maintaining joint stability only when necessary.
3Ease of operation
If a mobile hip joint prosthesis is used to allow natural movement, then movement freedom is improved, but the risk of dislocation and loosening increases due to abnormal strain
Solution Approach 1:
The prosthesis automatically transitions between mobile and locked states based on real-time monitoring of joint position and strain. During normal movement within safe parameters, the joint remains mobile for full range of motion. When abnormal movement patterns or strain levels indicate potential dislocation, the mechanism locks to prevent dislocation and loosening, providing reliability only when needed.
Solution Approach 2:
The prosthesis incorporates feedback mechanisms that continuously monitor joint position, movement range, and strain levels. This feedback information is used to control the locking mechanism, which engages or disengages automatically based on whether movement remains within safe parameters or exceeds thresholds that would cause dislocation or loosening.
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 enables the hip joint to maintain stability and functionality by allowing the prosthetic components to adjust and release under abnormal strain, reducing the risk of complications like loosening and femoral bone fracture without the need for surgical intervention.
Implementation Method 1
a releasing member adapted to, in a first state hold the first piece attached to the second piece, and in a second state release the first piece from the second piece. The releasing member is adapted to change from the first state to the second state when a pre-determined strain is placed on the releasing member.
Data Source
AI summary
A medical device for implantation in a hip joint of a patient is provided. The medical device comprises a first and second piece and a releasing member adapted to, in a first state hold the first piece attached to the second piece, and in a second state release the first piece from the second piece. The releasing member is adapted to change from the first state to the second state when a pre-determined strain is placed on the releasing member.