Trochlear Groove Resection Guide for Knee Prosthesis Alignment
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Solution Overview
Problem
Current patello-femoral joint replacement systems lack control over the shape and depth of resection in the trochlear groove of the femur, leading to inadequate restoration of the natural patella track and potential restriction of knee flexion during prosthesis implantation.
Innovation Solution
An elongate guide with multiple guide holes and a flexible sizing membrane is used to accurately position guide pins along the trochlear groove, allowing for precise placement of bone cutting instruments to create recesses that match the prosthesis, ensuring proper anatomical alignment and bone preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional resection instruments (osteotome, rasp, reciprocating saw, or burr) are used to remove bone in the trochlear groove region, then bone removal can be achieved, but there is very little control of the shape and depth of the resection
Solution Approach 1:
The guide is positioned and secured to the femur before bone resection begins. The guide includes pre-formed guide holes at specific locations and orientations that predetermined the exact path and depth of bone removal. This preliminary positioning and planning allows precise control of resection shape and depth while maintaining ease of operation through the pre-established guide structure.
Solution Approach 2:
The guide acts as an intermediary tool between the surgeon and the bone resection process. It provides a physical template with guide holes that translate the desired prosthesis geometry into precise bone removal paths. The guide mediates between the complex requirement for anatomically accurate resection and the simplicity of the surgical procedure, enabling precise control without complicating the operation.
2Manufacturing precision
If traditional resection instruments are used, then bone can be removed, but there is no true anatomically based means of restoring the trochlear groove or patella track
Solution Approach 1:
The guide is designed as a physical copy or template of the desired trochlear groove anatomy and prosthesis geometry. The guide holes are positioned to match the anatomical landmarks and curvature of the natural groove. By copying the target anatomy into the guide structure, the system achieves precise anatomical restoration without requiring complex real-time measurement or adjustment procedures.
Solution Approach 2:
The guide is divided into multiple sections with distinct guide holes positioned at specific locations (proximal, intermediate, distal sections). Each guide hole corresponds to a specific anatomical region and restoration requirement. This segmentation allows the complex restoration task to be broken down into multiple precise, controlled bone removal steps, each guided by a specific hole position, thereby achieving high anatomical accuracy without overwhelming complexity.
3Reliability
If the prosthesis is implanted without accurate restoration of the trochlear groove, then implantation can be performed, but the prosthesis may restrict flexion of the knee by raising the patella anteriorly
Solution Approach 1:
The guide provides visual and tactile feedback during the resection process. The guide holes and guide pins allow the surgeon to continuously monitor and adjust the bone removal to match the desired anatomical restoration. This feedback mechanism ensures that the patella track is accurately restored, preventing post-implantation flexion restriction while maintaining high precision in the restoration process.
Data Source
AI summary
The present invention relates to systems and methods for preparing the trochlear groove of a patient's femur to receive a prosthesis thereon. In the system, a combination drill-and-alignment guide includes at least a proximal and intermediate section, and preferably also includes a distal section. Guide holes for receiving guide pins therein are located in the proximal and distal sections of the guide. After the guide is positioned using at least one of several visual and/or tactile guide references in the system, the guides pins are placed through the guide holes of the guide and into bone. The guide may then be removed and replaced by cannulated reamers that are rotated and used to resect a predetermined amount of bone around the guide pins. A prosthesis having at least a portion of an outer surface that substantially matches the trochlear groove of the patient in a pre-degenerated state is then implanted on the resected bone.