Floating Patella Sensor for Robotic Knee Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for diagnosing knee joint injuries, particularly ACL tears, rely on subjective manual tests that are prone to variability and inconsistency, leading to potential misdiagnosis and inadequate treatment.
Innovation Solution
A robotic knee testing apparatus with a floating patella sensor and knee stabilizer that objectively measures residual movement of the femur and patella during testing, providing accurate and reproducible data on joint play and ligament damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual tests are used to diagnose knee joint injuries, then the testing process is simple and quick, but the diagnostic accuracy and consistency deteriorate due to subjective evaluation
Solution Approach 1:
The patent replaces manual mechanical testing with an automated robotic system that applies controlled forces and measures joint play objectively. The robotic apparatus uses motors and sensors to eliminate human subjectivity while maintaining efficient testing throughput.
Solution Approach 2:
The patent introduces a robotic intermediary between the clinician and the patient's knee joint. This intermediary executes standardized testing protocols with precise force application and measurement, removing the variable of clinician technique while preserving the benefits of automated data collection.
2Reliability
If a rigid sensor is used to measure joint movement, then the sensor provides stable readings, but it introduces friction and alters the natural movement being measured
Solution Approach 1:
The patent employs a flexible sensor assembly that can conform to the patella surface and move with the joint without creating significant friction. This flexible design allows the sensor to track natural joint movement while maintaining stable signal output.
Solution Approach 2:
The sensor system is designed to be dynamic rather than static, allowing the sensor to move with the joint components it measures. This dynamic coupling ensures the sensor follows natural joint kinematics without imposing rigid constraints that would alter the movement being measured.
3Measurement precision
If the patella is clamped firmly to prevent movement, then the sensor can accurately measure femur movement, but the clamping force alters joint mechanics and introduces measurement error
Solution Approach 1:
The patent applies differential clamping strategies where the sensor-contacting surface uses minimal force to allow natural patellar movement, while other portions of the stabilizer provide sufficient restraint to prevent unwanted degrees of freedom. This localized quality differentiation maintains joint mechanics while enabling accurate measurement.
Solution Approach 2:
The clamping mechanism is designed to be dynamically adjustable, allowing the system to adapt clamping forces based on the measurement phase and joint position. This dynamic adjustment prevents excessive restraint that would alter joint mechanics while ensuring sufficient stability for accurate measurement.
4Measurement precision
If multiple sensors are used to measure different aspects of joint movement, then measurement completeness improves, but device complexity and difficulty of calibration increase
Solution Approach 1:
The patent employs sensors with multi-functional capabilities where a single sensor assembly can measure multiple parameters (position, velocity, acceleration) and accommodate different measurement configurations. This universality reduces the total number of separate sensor components needed while maintaining comprehensive measurement coverage.
Solution Approach 2:
The patent combines multiple sensing functions into integrated sensor assemblies that can simultaneously or sequentially measure different aspects of joint kinematics. This merging approach reduces the number of separate calibration procedures needed compared to using multiple independent sensor systems.
Data Source
AI summary
A joint manipulation and evaluation apparatus has a mechanism configured to manipulate a first bone of a joint relative to a second bone of the joint. The apparatus has a joint stabilizer arranged to engage the joint and hold the second bone in place as the first bone is manipulated. A sensor is coupled to the joint stabilizer and is configured and arranged to detect residual movement of a clamped portion of the joint relative to the joint stabilizer as the first bone is manipulated.