Instrumented Knee Pivot Shift Apparatus for Rotational Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for evaluating rotational stability in ACL-reconstructed knees are subjective, variable, and lack sensitivity, making it difficult to assess the effectiveness of ACL reconstruction techniques and predict osteoarthritis development.
Innovation Solution
A mechanical pivot shift measurement apparatus that applies standardized dynamic loads to the knee joint, using a force-applying device with sensors to quantify rotational stability and kinematic signatures, allowing for more precise detection of rotational knee stability and comparison of ACL reconstruction techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual pivot shift maneuver is used to evaluate rotational stability, then clinical assessment can be performed, but the measurement is highly technique-dependent and variable among practitioners resulting in poor sensitivity and reproducibility
Solution Approach 1:
The patent replaces the manual mechanical assessment system with an instrumented device that applies standardized loads and measures rotational stability objectively. The device uses controlled mechanical loading combined with sensors to eliminate practitioner variability while maintaining clinical applicability.
Solution Approach 2:
The invention changes the measurement parameters from subjective clinical observation to objective quantitative data through instrumented loading. By standardizing the load application parameters and measuring the resulting kinematic responses, the system achieves consistent, reproducible measurements across different practitioners.
2Measurement precision
If standardized dynamic loads are applied through mechanical apparatus, then rotational stability can be quantified objectively, but the device complexity increases
Solution Approach 1:
The device is divided into functional modules: a loading mechanism for applying standardized forces, a sensing system for measuring kinematic responses, and a control system for coordinating operation. This segmentation allows each component to be optimized independently and simplifies the overall system architecture.
Solution Approach 2:
The patent introduces an intermediary measurement system that translates complex joint mechanics into quantifiable parameters. Sensors and transducers serve as intermediaries between the mechanical loading and the digital measurement system, enabling objective assessment without requiring overly complex direct measurement approaches.
3Difficulty of detecting and measuring
If different joint loading combinations are used to induce distinctive kinematic behavior, then rotational instability can be detected, but the results and interpretation become inconsistent between studies
Solution Approach 1:
The invention standardizes the loading parameters (force magnitude, direction, application point, and rate of application) to ensure that the same kinematic responses are elicited across different studies. This parameter standardization allows for consistent interpretation of rotational stability measurements regardless of when or by whom the test is performed.
Data Source
AI summary
An unmet need of orthopedic practitioners is a clinically-relevant measurement device and technique to objectively quantify joint (e.g., knee) stability, including rotational stability. An apparatus and method is disclosed for performing a mechanical joint movement test, such as a knee pivot shift test, through the application of standardized dynamic loads (e.g., using a constant-tension spring or other mechanism). When used for knee evaluation, this test reliably induces the characteristic “pivot” tibial subluxation/reduction event in an ACL-deficient knee, allowing for more sensitive detection of deficiencies in rotational knee stability, quantification of the relative importance of knee stabilizers, and comparison of the performance of contemporary ACL reconstruction techniques. The test allows for better understanding joint biomechanics and for defining unique kinematic and kinetic signatures for common joint injuries, such as knee injuries, that will be valuable for diagnostic purposes.