Patellar Kinematic Profiling for TKA Implant Positioning
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Solution Overview
Problem
Current methods for selecting patellar implants in total knee arthroplasty (TKA) are inadequate as they do not account for the complex biomechanics of the patellofemoral joint, leading to improper sizing and positioning that can result in patellar maltracking and other complications.
Innovation Solution
A surgical system and method that employs imaging and tracking technologies to dynamically track the patella throughout its range of motion, capturing multiple data points to create a detailed kinematic profile, compare it to a target profile, and suggest adjustments to implant position, size, and component type to ensure optimal joint function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current methods are used to select patellar implants based on limited knee flexion-extension positions, then the implant selection process is simple and quick, but the measurement precision and reliability of patellar kinematics assessment deteriorates
Solution Approach 1:
The patent segments the patella tracking into multiple discrete points (apex, medial edge, lateral edge) and multiple knee positions (0°, 30°, 60°, 90° flexion). This segmentation allows comprehensive kinematic assessment without requiring overly complex continuous tracking, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The system performs preliminary tracking and assessment of patellar kinematics before final implant selection. By capturing data at multiple predefined positions and calculating kinematic parameters in advance, the system enables informed implant selection without requiring complex real-time adjustments during surgery.
2Reliability
If anatomically shaped patellar implants are used, then rehabilitation outcomes are improved, but the manufacturing precision and positioning difficulty increases due to complex geometric configuration
Solution Approach 1:
The patent calculates specific kinematic parameters (anterior-posterior translation, medial-lateral translation, rotation) at multiple knee flexion positions to characterize the patient's native patellar movement. These quantified parameters guide the selection and positioning of anatomically shaped implants, transforming complex geometric challenges into manageable parameter-based decisions.
Solution Approach 2:
The system provides feedback on measured patellar kinematics compared to desired kinematic profiles. This feedback loop enables surgeons to adjust implant positioning and selection to achieve optimal rehabilitation outcomes while managing the complexity of anatomical implant configuration.
3Measurement precision
If dynamic tracking throughout the entire range of motion is implemented, then the measurement precision of patellar kinematics is improved, but the time required for assessment and the device complexity increase
Solution Approach 1:
The patent employs periodic measurement at discrete knee flexion positions (0°, 30°, 60°, 90°) rather than continuous tracking. This periodic sampling captures essential kinematic information throughout the range of motion while significantly reducing the time and complexity compared to continuous dynamic tracking.
Solution Approach 2:
The system captures kinematic data at selected key positions within the full range of motion rather than every possible position. This partial action approach provides sufficient precision for implant selection without the time cost of complete continuous tracking, achieving an optimal balance between measurement quality and surgical efficiency.
Data Source
AI summary
Disclosed herein is a method for patella planning. The method can include tracking a location of a point adjacent an unresected patella in flexion and extension of a knee, generating a native kinematic profile from the location of the point, and displaying and comparing the native kinematic profile with a target kinematic profile. The native kinematic profile can represent a kinematic profile of the unresected patella. The method can include using the native kinematic profile prior to bone resections if the native kinematic profile is within predetermined thresholds of the target kinematic profile, performing pre-resection steps prior to bone resections if the native kinematic profile is outside predetermined thresholds of the target kinematic profile.