Modular Rotational Prosthesis Design for Controlled Torsional Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing orthopedic implant technologies, such as humeral and femoral prostheses, fail to adequately stabilize against torsional stresses, leading to joint dislocation and damage due to their fixed rotational designs, limiting the range of motion and causing additional trauma.
Innovation Solution
A modular rotational device with a threaded coupler, housing, and lobe ring system that reduces rotational friction and limits excessive rotation, featuring biocompatible materials and adjustable rotational stops to stabilize the prosthesis against torsional stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed rotational design is used in existing prostheses, then the structure is simple and stable, but excessive torsional stresses cause joint dislocation and damage
Solution Approach 1:
The patent applies the dynamics principle by introducing a modular rotational device that allows controlled rotation of the prosthesis shaft relative to the housing. The rotational mechanism with adjustable stops transforms the fixed design into a dynamic system that can accommodate physiological torsional movements while maintaining stability, thereby reducing excessive torsional stresses that cause joint dislocation and damage.
Solution Approach 2:
The patent applies segmentation by dividing the prosthesis into modular components: a housing, a rotational device with threaded coupler, and a shaft that can rotate independently. This modular design allows the rotational element to be positioned at optimal locations and enables independent optimization of each component to handle torsional loads effectively.
2Reliability
If a modular rotational device is introduced to reduce torsional stress, then joint stability improves, but device complexity increases
Solution Approach 1:
The patent applies the intermediary principle by introducing a rotational device as a mediator between the fixed housing and the movable shaft. This intermediate component with threaded coupler and rotational stops absorbs and manages torsional stresses, protecting the joint while maintaining a relatively simple overall structure through standardized mechanical elements.
3Ease of operation
If rotational friction is reduced to allow motion, then range of motion improves, but control over rotation is lost
Solution Approach 1:
The patent applies parameter changes by incorporating adjustable rotational stops that can be positioned at specific angles. This allows the system to maintain low friction for smooth motion within the permitted range while providing controlled limits to prevent excessive rotation. The friction characteristics and rotational limits are adjustable parameters that can be optimized for different applications.
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 enhanced stability and reduced rotational friction, preventing joint dislocation and damage by allowing controlled motion, improving the functionality and durability of orthopedic implants.
Implementation Method 1
a proximal sleeve positioned within the housing proximal end axial bore, the proximal sleeve having an axial bore therethrough for receiving the elongated stem, the proximal sleeve reducing the rotational friction of the elongated stem with respect to the housing proximal end; a distal sleeve positioned within the housing distal end axial bore, the distal sleeve having an axial bore therethrough for receiving the elongated stem; the distal sleeve reducing the rotational friction of the elongated stem with respect to the housing distal end
Data Source
AI summary
An improved modular rotational device includes a first and second threaded coupler for affixation along the stem of an endoprosthetic device, for example, a humeral prosthesis or a femoral prosthesis. The rotational device axis of rotation is coaxial with the stem, and its axis of rotation is located in close proximity to the intramedullary stem of the prosthesis or in close proximity to the distal articulation of the prosthesis. A housing has a proximal and distal end with an axial bore therethrough for receiving an elongated stem of the device. A lobe ring may be utilized to limit the axis of rotation of the device. Additional endoprosthetic devices may be attached to male or female threaded couplers, or to Morse tapers. A plurality of suture attachments facilitates attachment of soft tissue thereto.