Digital Knee Tensioner for Objective Joint Laxity Measurement
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Solution Overview
Problem
Existing orthopaedic implant procedures face challenges in accurately characterizing soft tissue properties and applying consistent forces during joint replacement surgeries, leading to inconsistent surgical outcomes due to subjective assessments and limited pre-operative joint tensioning capabilities.
Innovation Solution
A tensioner tool with force and positional sensors, coupled with a processor, to quantify joint tension by measuring applied forces and separation distances, providing real-time data for improved joint laxity assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional manual assessment methods are used to evaluate soft tissue tension, then the surgical procedure is simple and quick, but the measurement precision and objectivity are insufficient leading to inconsistent outcomes
Solution Approach 1:
The patent replaces manual mechanical assessment with electronic sensing systems. Force sensors measure the force applied during joint distraction, while positional sensors track the separation distance between bone segments. This substitution of mechanical judgment with electronic measurement directly improves measurement precision while the modular sensor design keeps device complexity manageable.
Solution Approach 2:
The patent introduces sensors as intermediary elements between the surgeon's manual tensioning action and the measurement system. The force sensor acts as an intermediary to capture the applied force, while positional sensors serve as intermediaries to measure separation distance. These intermediaries enable objective quantification without requiring the surgeon to directly interpret complex tactile feedback.
2Reliability
If pre-operative joint tensioning is performed to assess soft tissue properties, then more accurate implant fitting can be achieved, but the device profile must be narrow enough to fit in tight pre-operative joint anatomy
Solution Approach 1:
The patent divides the tensioner tool into separate functional modules: force sensing elements, positional sensing elements, and actuation components. This segmentation allows each component to be minimized in size for insertion through narrow pre-operative joint spaces, while the integrated system provides comprehensive joint laxity assessment capability when all components are assembled and functioning together.
Solution Approach 2:
The patent employs a nested configuration where sensors and measurement components are integrated within the structural elements of the tensioner tool. The force sensors are embedded in the distraction mechanism, and positional sensors are incorporated into the arm structure, allowing the measurement system to be contained within the minimal external profile required for pre-operative insertion.
3Loss of information
If force is applied subjectively by hand or conventional tools, then the surgical procedure is straightforward, but the quantification of soft tissue response is inconsistent
Solution Approach 1:
The patent implements feedback mechanisms where force sensors continuously measure the force applied during joint distraction and positional sensors track the resulting separation distance. This real-time feedback provides objective data about soft tissue response, eliminating the information loss associated with subjective manual assessment while maintaining surgical simplicity through automated measurement and display of tensioning parameters.
Data Source
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AI summary
A tensioner tool for assessing joint laxity is disclosed. The tensioner tool comprises a pair of pivotally coupled arms, each arm comprising a proximal handle portion, a distal portion, and an insertion tip selectively coupled to the distal portion. The pair of arms pivot between a compressed configuration for insertion within the joint and an expanded configuration for distraction of the joint by applying a force to the handles, thus spreading the insertion tips. The tensioner tool also comprises a force sensor configured to measure the force applied to the handle portion and a positional sensor configured to measure a separation distance between the pair of arms. The tensioner tool also comprises a processor configured to calculate a distraction force at the insertion tips based on the measured force and to calculate a tip distance between the insertion tips based on the measured separation distance.