Hip Offset Balancing Tool With Force Feedback and Auto Adjustment
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Solution Overview
Problem
Current hip joint replacement surgeries rely on subjective 'feel' and trial-and-error for soft tissue tensioning, leading to inconsistent results, prolonged surgical times, and lack of objective measurement for optimal joint balance.
Innovation Solution
A hip joint balancing system with a femoral head offset tool incorporating force sensors, an IMU, and a spring-loaded ratcheting mechanism that automatically adjusts the femoral head offset to achieve force equilibrium, providing real-time feedback and objective measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surgeons use subjective feel and trial-and-error with multiple component sizes to achieve proper hip joint balancing, then they can perform the surgery with available tools, but the surgical time is extended and results are inconsistent
Solution Approach 1:
The system incorporates force sensors that provide real-time quantitative feedback on soft tissue tensions during range of motion testing. This objective feedback allows surgeons to immediately assess whether the hip joint is properly balanced, eliminating the need for extended trial-and-error with multiple component sizes and enabling consistent, reliable results without extending surgical time.
Solution Approach 2:
The patent replaces the traditional mechanical trial-and-error approach with an integrated sensor system that uses force sensors and computer navigation to objectively measure soft tissue tensions. This substitution of mechanical trial components with electronic sensing and data processing enables rapid, consistent assessment of hip joint balance, resolving the contradiction between reliability and surgical time.
2Measurement precision
If computer navigation systems are used to provide position data, then positioning accuracy is improved, but the systems do not integrate with adjustment devices and require additional setup time
Solution Approach 1:
The patent merges the computer navigation system with the adjustment device into a single integrated system. The force sensors are incorporated directly into the adjustment mechanism, and the computer program receives data from both the navigation system and force sensors, providing unified real-time guidance for both positioning and soft tissue tension assessment without requiring separate setup procedures.
Solution Approach 2:
The integrated system performs multiple functions simultaneously: it provides position data through computer navigation, measures soft tissue tensions via force sensors, and guides adjustment decisions through unified software. This multi-functionality eliminates the need for separate navigation and adjustment devices, reducing setup time and complexity while maintaining high positioning accuracy.
3Manufacturing precision
If multiple component sizes are tried to achieve optimal soft tissue tension, then proper joint balance can be found, but the process lacks quantitative measurement and produces inconsistent results
Solution Approach 1:
The force sensors provide real-time quantitative feedback on soft tissue tensions, converting the subjective assessment into objective numerical data. This feedback enables precise determination of optimal soft tissue tension without needing to try multiple component sizes, as the sensor system directly measures whether the desired tension level is achieved with the current configuration.
Solution Approach 2:
The patent replaces the mechanical trial-and-error method of trying multiple component sizes with an electronic sensing system that quantitatively measures soft tissue tensions. This substitution preserves all relevant information about tissue tension levels, eliminating the information loss that occurs when surgeons rely on subjective feel and discarded trial components.
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
Reduces surgical time, improves consistency, and ensures optimal soft tissue balance by objectively measuring and adjusting soft tissue tensions during hip arthroplasty.
Implementation Method 1
The spring system is configured to automatically adjust femoral head offset by moving the head relative to the collar by applying spring force against soft tissue resistance
Implementation Method 2
force sensors to measure multi-axis forces transmitted through the tool during range of motion testing
Implementation Method 3
an IMU to measure orientation data
Implementation Method 4
spring-loaded ratcheting mechanism
Data Source
AI summary
A hip balancing sensor system with an integrated ratcheting adjustment mechanism is provided for determining an optimal femoral head offset during hip arthroplasty. The system includes a femoral head offset tool with a head containing a chamber and a collar configured to attach to a femoral stem. The tool comprises force sensors, an IMU, and a spring system configured to automatically adjust femoral head offset by moving the head relative to the collar within a chamber of the head until force equilibrium is achieved. The head is configured to interface with various acetabular structures including acetabular cups, native acetabulum, or acetabular defects. A sensing controller monitors the adjustment process and detects when spring force equals soft tissue resistance indicating optimal positioning. Upon achieving equilibrium, the surgeon measures the femoral head offset distance using a sizing tool and selects a permanent femoral head implant.