Osseointegrated Prosthetic Attachment Device for Natural Wrist Rotation
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Solution Overview
Problem
Traditional socket attachments for prosthetic limbs often cause dermatological issues and limit range of motion in amputees, particularly those with trans-radial amputations, due to the complex anatomy of the forearm bones and varying amputation levels, necessitating an adjustable and flexible connection mechanism.
Innovation Solution
An attachment device with a base plate, holders, a locking plate, and flexible members that allow for adjustable positioning and movement in multiple directions, enabling rotation and tilting to accommodate different bone configurations, while preventing unwanted movement, and incorporating features like slider elements and strain gauges for stability and stress detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional socket attachment is used to connect the prosthesis to the residual limb, then the prosthesis can be attached to the limb, but dermatological problems occur and the range of motion is limited
Solution Approach 1:
The invention extracts the prosthesis attachment from the soft tissue socket interface and relocates it to the skeletal system through osseointegrated implants. The attachment device connects directly to implants in the radius and ulna bones, eliminating the need for socket contact with the residual limb skin, thereby solving dermatological problems while maintaining secure attachment
Solution Approach 2:
The invention introduces osseointegrated implants as an intermediary between the prosthesis and the residual limb. These titanium implants integrate with the bone structure and serve as a stable anchor point, transferring the attachment function from soft tissue to the skeletal system, thus avoiding skin-related issues
2Reliability
If a fixed attachment device is used to connect the prosthesis to the implants, then the connection is stable, but it cannot accommodate varying bone configurations and amputation levels
Solution Approach 1:
The attachment device incorporates dynamic adjustment capabilities through movable holders that can be repositioned along the longitudinal axis of the bone implants. This allows the device to adapt to different amputation levels and bone configurations while maintaining stable connection, transforming a fixed structure into an adjustable one
Solution Approach 2:
The attachment device is divided into separate modular components including a base plate, individual holders for each implant, and adjustable connection elements. This segmentation allows independent positioning of each holder to match the specific anatomical configuration of the patient's residual limb and bone structure
3Adaptability or versatility
If the holders are allowed to move freely in all directions, then the device can accommodate varying bone configurations, but unwanted movement and instability occur
Solution Approach 1:
The holders are designed with selective mobility, allowing movement only in the longitudinal direction along the bone implant axis. Lateral and rotational movements are constrained by guide structures and engagement features, providing dynamic adjustability where needed while maintaining stability in other degrees of freedom
Solution Approach 2:
Different portions of the holder structure have different mobility characteristics. The lower portion allows longitudinal adjustment for positioning, while the upper connection portion provides stable, fixed attachment to the prosthesis. This local differentiation of mobility properties enables both adjustability and stability
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 a stable, flexible, and modular connection that allows natural wrist rotation and accommodates varying bone configurations, enhancing the usability and reliability of osseointegrated prostheses by allowing precise adjustment and monitoring of stress, thus improving the quality of life for amputees.
Implementation Method 1
at least one flexible member arranged between each of the first and second holder and the base plate, the flexible member being flexible in the z-direction and configured to allow a movement of the first and second holder in the z-direction in relation to the base plate and to allow the first and second holder to tilt with respect to the xy-plane of the base plate
Data Source
AI summary
The present invention relates to a an attachment device for attaching a prosthesis to a bone, comprising: a base plate having an extension in an xy-plane; a first holder for holding a first abutment; a second holder for holding a second abutment; a locking plate attached to the base plate to restrict movement of the holders in a z-direction away from the base plate. The locking plate is configured to allow rotation of the first and second holder around a z-axis perpendicular to the xy-plane. The locking plate and the base plate is configured to allow movement of the first holder along the x-direction and to prevent movement the y-direction and to prevent movement of the second holder in the x- and y-direction. At least one flexible member is arranged between each of the first and second holders and the base plate, the flexible member being flexible in the z-direction to allow movement of the first and second holder in the z-direction and to allow the first and second holder to tilt with respect to the xy-plane.