Knee Goniometer Heel Height Measurement for Extension Accuracy
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Solution Overview
Problem
Current knee goniometers rely on user expertise and perspective for accurate angle measurements, leading to variability in measurements between users and models, and do not provide a consistent method for assessing knee extension, hyperextension, or extensor length, especially in post-surgical rehabilitation where precise measurement is crucial.
Innovation Solution
A knee goniometer device that measures heel height difference while the patient is lying prone, allowing for precise assessment of knee joint extension or hyperextension by using an elongated ruler member and movable member with calibrated indicia, ensuring accurate and consistent measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard disc goniometer is used to measure knee extension, then angle measurement can be obtained, but measurement precision deteriorates due to reliance on user expertise and perspective
Solution Approach 1:
The patent replaces the traditional mechanical disc goniometer system with a heel height difference measurement system. Instead of using a disc-based angle measurement tool that requires user alignment, the invention uses a simple ruler or measuring device to measure the vertical height difference between heels, eliminating the need for complex mechanical alignment and user expertise while improving measurement consistency.
2Loss of information
If a disc goniometer is used for knee extension measurement, then angle data can be collected, but device complexity increases due to alignment requirements
Solution Approach 1:
The patent extracts the essential measurement function from the complex disc goniometer system. By taking out only the height measurement capability and applying it to heel height difference, the invention eliminates the complex alignment procedures, reference arm positioning, and angle reading mechanisms while retaining the core function of assessing knee extension.
3Reliability
If heel height difference measurement method is used, then measurement consistency improves, but ease of operation may worsen due to patient positioning requirements
Solution Approach 1:
The patent employs a patient positioning method where the patient lies prone with knees off the table, allowing gravity to naturally position the legs in a neutral alignment. This self-positioning approach reduces the need for complex manual manipulation by the practitioner while maintaining measurement consistency, as the patient's own body weight and anatomy facilitate proper positioning.
Data Source
AI summary
A device and method for measuring the amount of knee extension loss, hyperextension, or extensor length associated with arthritis, trauma, surgery or other medical conditions. This device and method includes measuring the difference in heel heights of a patient while patient is lying prone on a table with their legs, at the level of their knee caps, off the table. This device and method also measures extensor length in a patient's knee joint, by assessing heel height difference while a patient is lying prone on a table with a prone knee bend. This device and its methods provide accurate distance measurements that correlate to knee straightness and flexibility; these distinguishing metrics are unattainable by a standard “disc” goniometer. In addition, this device permits convenient measuring of a knee's mobility for two unique perspectives, namely in prone with legs straight or with a knee bent.