Adjustable Offset Bushing for Orthopaedic Implants
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Solution Overview
Problem
Conventional orthopaedic implants with centrally located stems often interfere with the non-centrally located intramedullary canals of the tibia or femur, requiring trial and error with multiple pieces to determine the correct offset for proper positioning.
Innovation Solution
An adjustable offset bushing system with a tibial template, bushing guide, and rotatable offset bushing, allowing precise measurement of offset magnitude and orientation using indicia and detents, enabling optimal coverage of the resected bone surface without the need for multiple pieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pieces of offset bushings with different offset distances are used, then the correct offset magnitude can be determined, but the trial and error method increases the time and complexity of the procedure
Solution Approach 1:
The offset bushing incorporates a rotatable mechanism with a trigger flange that can slide along the bushing body. This dynamic element allows the surgeon to adjust and measure offset magnitude continuously rather than switching between multiple fixed bushings, eliminating the trial and error process while maintaining measurement precision.
Solution Approach 2:
The bushing body features a groove with multiple detents at different positions, allowing the trigger flange to be positioned at various offset distances. This provides a range of adjustable offset parameters within a single bushing, replacing the need for multiple separate bushings with different fixed offset values.
2Measurement precision
If multiple pieces of offset bushings are used to determine correct offset, then accurate measurement is achieved, but the device complexity and number of components increase
Solution Approach 1:
Multiple offset measurement functions are merged into a single offset bushing component. The rotatable bushing with trigger flange and detent mechanism integrates what would otherwise require multiple separate bushings, reducing device complexity while maintaining measurement precision through the adjustable mechanism.
Solution Approach 2:
The offset bushing serves multiple functions: it provides a range of offset distances through the trigger flange positioning, allows rotational adjustment for orientation measurement, and includes detents for stable positioning. This multi-functional design replaces multiple specialized bushings, reducing overall system complexity.
3Measurement precision
If an adjustable offset bushing with rotatable mechanism is used, then both offset magnitude and orientation can be measured, but the mechanism complexity increases
Solution Approach 1:
The bushing incorporates a rotatable mechanism with a trigger flange that can slide along the bushing body. This dynamic element allows the surgeon to adjust and measure offset magnitude continuously rather than switching between multiple fixed bushings, eliminating the trial and error process while maintaining measurement precision.
Solution Approach 2:
The trigger flange acts as an intermediary element between the surgeon's manipulation and the measurement function. By sliding the trigger flange along the grooved bushing body, the surgeon can indirectly adjust and read offset measurements without directly complex mechanisms, simplifying the user interaction despite the internal mechanical complexity.
Data Source
AI summary
An orthopaedic instrumentation having an intermediate piece that has an opening for receiving an intramedullary reference. The intermediate piece such as a tibial template or a cutting guide is located on the resected tibia or femur in a manner that it optimally covers the resected surface of the tibia or the femur. A bushing guide is provided for mounting on the intermediate piece. The bushing guide has a circular opening. An offset bushing is rotatably mounted in the opening in the bushing guide. A trigger flange is slidably mounted on the offset bushing. The trigger flange can slide back and forth relative to the offset bushing. An indicia is formed on the upper surface of trigger flange. The indicia when aligned with one of the indicia on the offset bushing body measures the offset of center of a bore in the trigger flange from center of the offset bushing. The offset bushing can rotate around its longitudinal axis in the opening in the bushing guide. Indicia on the offset bushing may be used to measure the orientation of the center of the hole in the trigger with respect to the center of bushing body.