Hip Soft Tissue Tension Assessment Using Navigation-Tracked Shuck Vectors
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Solution Overview
Problem
Existing total hip arthroplasty procedures lack objective methods to measure soft tissue tension in the hip joint, relying heavily on subjective surgeon judgment, which affects the accuracy of implant component positioning and post-operative biomechanics.
Innovation Solution
A digital output shuck test using navigation and software to track real-time positions of the femur and pelvis, measuring a shuck length vector to objectively assess soft tissue tension, and providing guidelines for adjusting implant size or geometry based on quantified results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subjective tests (shuck test, kick test) are used to assess soft tissue tension, then the surgeon can obtain a feel for tissue tension, but the results remain subjective and unreliable due to reliance on surgeon judgment
Solution Approach 1:
The patent replaces the subjective mechanical assessment method (surgeon's manual shuck test) with an optical measurement system using cameras and coordinate tracking to objectively measure soft tissue tension through distraction vectors, eliminating reliance on surgeon judgment while maintaining operational simplicity
Solution Approach 2:
The patent introduces an intermediary measurement system (camera-based navigation system) that acts as a mediator between the surgeon's manual distraction maneuver and the final assessment, translating subjective physical manipulation into objective quantitative data through coordinate tracking and vector calculation
2Productivity
If traditional shuck test is performed without quantitative measurement, then the procedure remains simple and quick, but it does not provide reliable or objective measure of soft tissue tension
Solution Approach 1:
The patent maintains continuous real-time tracking of femur and pelvis positions throughout the distraction maneuver, allowing the surgeon to perform the shuck test at normal speed while the system continuously captures coordinate data to generate reliable quantitative measurements without interrupting the surgical workflow
Solution Approach 2:
The patent substitutes the lack of measurement capability in traditional shuck test with an optical tracking system that automatically calculates distraction vectors from recorded coordinates, providing reliable objective measurement without adding manual measurement steps that would slow down the procedure
3Device complexity
If implant component positioning is based on subjective judgment, then the surgical process remains straightforward, but accurate restoration of pre-disease biomechanics including center of rotation, leg length and offset cannot be achieved
Solution Approach 1:
The patent implements feedback by displaying calculated distraction vector magnitudes and directions to the surgeon in real-time, allowing immediate assessment of soft tissue tension and guiding adjustments to implant positioning to achieve accurate restoration of biomechanics while maintaining procedural simplicity
Solution Approach 2:
The patent introduces a computational intermediary that processes tracked coordinates to calculate distraction vectors and provides quantitative guidance for implant positioning, bridging the gap between simple surgical maneuvers and precise biomechanical restoration without increasing operational complexity
4Ease of operation
If no objective measurement of soft tissue tension is available, then the surgical workflow remains simple, but accurate soft tissue balance in post-operative hip joints cannot be achieved
Solution Approach 1:
The patent enables the measurement system to automatically calculate distraction vectors and provide soft tissue tension assessment without requiring additional manual measurement steps from the surgeon, maintaining workflow simplicity while delivering precise quantitative data for achieving accurate soft tissue balance
Solution Approach 2:
The patent replaces the absence of objective measurement with an automated optical tracking and calculation system that derives soft tissue tension data from recorded coordinates, achieving precise soft tissue balance assessment without adding manual complexity to the surgical workflow
Data Source
AI summary
A method of evaluating soft tissue tension surrounding a hip of a patient uses navigation and software to track positions of a femur and a pelvis of the patient in real time. The method begins with intra-operative reduction of a femoral implant into an acetabulum of a patient and retrieval of first coordinates of a femoral head center of the femoral implant when the femoral implant is in a reduced position. Performance of a shuck test follows where the femur is distracted relative to the acetabulum. Retrieval of second coordinates of the femoral head center occurs when the femoral implant is distracted from the acetabulum, and a difference between the first coordinates and the second coordinates in a coronal plane is used to determine a shuck length vector.