Intramedullary Canal Registration for Accurate Knee Stem Alignment
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Solution Overview
Problem
Variations in human anatomy, particularly in bones such as the tibia and femur, necessitate precise alignment and orientation of implants during knee arthroplasty procedures to avoid improper positioning and pain, which existing systems fail to address uniformly.
Innovation Solution
A computer-assisted surgical system (CASS) utilizing electromagnetic tracking systems with multiple small diameter sensors and a coupler stem connection that allows for variable alignment to anatomical or kinematic alignment, accommodating bone deformities and muscle structures, and includes a robotic arm for precise instrument guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standard tibial stem is implanted along the mechanical axis, then implantation is simplified, but improper positioning occurs in patients with bowed intramedullary canals causing pain
Solution Approach 1:
The system dynamically adapts the stem alignment based on real-time tracking of the intramedullary canal geometry. Instead of using a fixed mechanical axis alignment, the registration system allows the stem axis to be adjusted to match the actual canal path, accommodating variations such as valgus bowing while maintaining precise positioning through computer-assisted guidance.
2Reliability
If offset alignment is used to accommodate anatomical variations, then proper positioning is achieved, but the complexity of alignment increases
Solution Approach 1:
The patent replaces complex mechanical alignment tools and manual measurement techniques with an electromagnetic tracking system and computer-assisted registration. The system uses sensors to track the intramedullary canal geometry and automatically calculates the optimal stem alignment, eliminating the need for complex physical alignment devices while achieving precise positioning.
3Device complexity
If manual alignment methods are used, then device complexity is reduced, but measurement precision and alignment accuracy deteriorate
Solution Approach 1:
The system creates a digital copy or model of the patient's intramedullary canal geometry through electromagnetic tracking and registration. This virtual model allows for precise measurement and planning of stem alignment without requiring complex physical measurement tools during surgery. The registered canal path is then used to guide stem implantation with high accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and efficient implant placement by compensating for individual anatomical variations, reducing the risk of improper positioning and associated pain, and enhancing surgical precision.
Implementation Method 1
A computer-assisted surgical system (CASS) utilizing electromagnetic tracking systems with multiple small diameter sensors
Data Source
AI summary
Methods and systems for identifying and determining the size and orientation of a reamed portion of a patient's bone are disclosed. A tracking array and/or point probe may be inserted into an adapter device. The adapter device comprising a plurality of openings, having various connection means therein, such that when the tracking array is inserted into the adapter, a secure and robust connection is created. A reamer, stem, or similar tool may then be inserted into the opposing side of the adapter, during which, a secure and robust connection is created between the adapter and the tool. Thus, through the use of Computer Assisted Surgery Systems, a more accurate representation of the patient's anatomy can be obtained.