Tensor Device for Revision Knee Arthroplasty Precision
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Solution Overview
Problem
In revision knee arthroplasty, the removal of existing implants often damages the bone and ligaments, leading to precision issues during the placement of new implants due to altered bone surfaces and abnormal ligament tension.
Innovation Solution
A tensor device is used in conjunction with a robotic surgical device to improve precision in revision knee arthroplasty by providing accurate and quick gap balancing information, joint line information, and implant sizing, which helps in precise alignment and positioning of new implants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cutting blocks and bone landmarks are used for defining orientation during implant removal, then the surgical procedure can be performed with standard equipment, but the precision of bone surface machining deteriorates due to altered or removed bone landmarks
Solution Approach 1:
The patent applies preliminary action by pre-operatively scanning the patient's anatomy to create a 3D model and pre-planning the implant removal procedure. This allows the surgical guide to be designed beforehand with precise bone surface machining instructions, compensating for the loss of bone landmarks during implant removal. The pre-planned approach enables the surgical guide to account for altered anatomy before the surgery begins, thereby maintaining manufacturing precision without requiring complex intraoperative adjustments.
Solution Approach 2:
The patent introduces a surgical guide as an intermediary device between the planning software and the actual bone machining process. This surgical guide acts as a mediator that translates the pre-operative 3D plan into precise intraoperative guidance for bone surface preparation. The guide includes features that interface with the patient's anatomy and the machining tool, enabling accurate bone surface machining even when traditional bone landmarks are altered or removed, thus resolving the precision issue without requiring complex real-time adjustments.
2Measurement precision
If computer-assisted surgery devices are used to improve precision in orthopedic joint repair, then the accuracy of implant positioning is improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies the copying principle by creating a digital 3D model (virtual copy) of the patient's anatomy through pre-operative scanning. This digital replica allows for precise planning and simulation of the implant removal and positioning procedure without requiring complex robotic or navigation systems during surgery. The virtual model is then used to design a custom surgical guide that physically guides the surgical instruments, thereby achieving high measurement precision through a simplified system that combines digital planning with physical guidance.
Solution Approach 2:
The patent replaces complex mechanical computer-assisted surgery systems (such as robotic arms or intraoperative navigation equipment) with a simpler system based on a pre-designed surgical guide. The surgical guide incorporates all the positioning information from the digital plan, allowing the surgeon to achieve accurate implant positioning through direct mechanical guidance rather than complex real-time computational systems. This substitution reduces device complexity while maintaining measurement precision.
Data Source
AI summary
Systems and methods may use a tensor device in various aspects of a knee revision. For example, the tensor device may include a femoral arm configured to couple with an end portion of a femoral intramedullary canal reamer and a tibial arm moveably connected to the femoral arm, the tibial arm configured to couple with an end portion of a tibial intramedullary canal reamer. The tensor device may include a component or be used to identify a knee gap or a component size for an implant.