Arm Angle Indicator for Shoulder Replacement Surgery
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Solution Overview
Problem
Current methods for determining the version angle of the humeral head during shoulder replacement surgery lack precision and consistency, as they rely on visual estimation and vary in technique, which can lead to inaccuracies in setting the humeral component's retroversion angle.
Innovation Solution
An arm angle measurement device with a pivotal connection between the forearm and upper arm, featuring an angle indicator with markings and a locking mechanism, allowing surgeons to accurately dial in the desired version angle of the humeral head, ensuring consistent and precise measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual estimation method is used to determine version angle, then the surgical procedure is simple and quick, but the measurement precision and consistency deteriorate
Solution Approach 1:
The patent introduces an angle indicator device as an intermediary tool between the surgeon's visual estimation and the actual measurement. The device includes a protractor-like indicator with degree markings that physically overlays the humeral head, providing an objective reference framework. This intermediary tool translates the subjective visual estimation into objective measurable angles, resolving the contradiction between simplicity and precision.
Solution Approach 2:
The patent replaces the purely visual/mechanical estimation method with a standardized angular measurement system. By introducing a protractor-based indicator with predefined degree markings (0°, 15°, 30°, 45°, 60°, 75°, 90°), the system substitutes subjective visual judgment with objective mechanical measurement, achieving consistent and precise version angle determination without significantly increasing procedural complexity.
2Reliability
If visual estimation method is used to determine version angle, then the surgical procedure remains simple, but the consistency of measurement deteriorates
Solution Approach 1:
The angle indicator device is designed as a universal tool that can be applied to any humeral head regardless of patient anatomy or surgical approach. The protractor-like indicator with standardized degree markings provides a consistent reference system for all measurements, ensuring that the same measurement criteria are applied uniformly across different patients and surgical situations, thereby improving reliability without adding complex patient-specific customization.
Solution Approach 2:
The patent transforms the measurement parameter from subjective visual estimation to objective angular measurement with standardized degree increments. By defining specific angular parameters (0° parallel to sagittal plane, 15°, 30°, 45°, 60°, 75°, 90° perpendicular to sagittal plane), the system ensures consistent parameter measurement across different surgeons and cases, enhancing reliability while maintaining procedural simplicity.
3Measurement precision
If standardized angle measurement device is introduced, then measurement precision and consistency improve, but the surgical procedure becomes more complex
Solution Approach 1:
The angle indicator device is segmented into distinct functional components: a protractor-like indicator body with degree markings, a positioning mechanism for aligning with the humeral head, and reference lines indicating different version angles. This segmentation allows each component to perform its specific function efficiently, making the overall device easy to operate despite its enhanced measurement capabilities. The modular design enables quick alignment and reading without requiring complex manipulation.
Data Source
AI summary
An angle measurement device is provided for determining the version angle for the prosthetic humeral head during shoulder replacement surgery. The device has a first collar for contacting the forearm and has a first coupling element in the form of a rod aligned with the ulna. The device has a second collar for contacting the upper arm when the elbow is flexed to 90°. The second collar has a second coupling element coupled thereto extending in a direction generally perpendicular to the humerus. The second coupling element is pivotally coupled to the first coupling element for rotation about a pivot point axis. An angle indicator having angle indicia is located at said pivot point and fixed to one of said first or second arm contacting collars for indicating the angle between the ulna and the humerus during external rotation of the forearm.