Simplified Bone Resection Jig for Knee Replacement
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Solution Overview
Problem
Existing bone resection jigs for knee joint replacement surgery are complex, require proficiency, and prolong surgical time due to numerous moving parts and adjustment steps, making them cumbersome and expensive.
Innovation Solution
A simplified bone resection jig comprising a spacer block, reference pin guide, and aiming member that ensures consistent ligament tension between extension and flexion positions, allowing for accurate resection plane setting without interfering with the patellar tendon, and enabling easy operation with minimal skill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a complex bone resection jig with many moving parts and adjustment parts is used to ensure accurate resection, then manufacturing precision is improved, but device complexity increases and ease of operation deteriorates
Solution Approach 1:
The jig is divided into separate functional modules: a positioning member with positioning pins for establishing the resection plane, a spacer block for maintaining the resection interval, and a reference member for guiding the resection. Each module performs a specific function independently, simplifying the overall design while maintaining precision.
Solution Approach 2:
The positioning pins are inserted into the bone surface before resection to pre-establish the resection plane. The spacer block is positioned beforehand to define the correct resection interval. This preliminary positioning eliminates the need for complex adjustments during the resection process.
2Manufacturing precision
If a bone resection jig with numerous operation steps and adjustment parts is used to achieve precise resection, then manufacturing precision is improved, but ease of operation deteriorates
Solution Approach 1:
The positioning pins are inserted into the bone surface before resection to pre-establish the resection plane. The spacer block is positioned beforehand to define the correct resection interval. This preliminary positioning eliminates the need for complex adjustments during the resection process.
Solution Approach 2:
The positioning pins automatically self-align with pre-drilled holes in the bone, and the spacer block self-positions against the positioning pins. This self-aligning mechanism eliminates the need for complex adjustment procedures by the surgeon.
3Manufacturing precision
If a bone resection jig with many moving parts is used to ensure accurate resection, then manufacturing precision is improved, but weight increases
Solution Approach 1:
The jig is divided into separate functional modules: a positioning member with positioning pins for establishing the resection plane, a spacer block for maintaining the resection interval, and a reference member for guiding the resection. Each module performs a specific function independently, simplifying the overall design while maintaining precision.
Solution Approach 2:
Instead of using a heavy, complex jig that actively enforces positioning, the invention uses lightweight positioning pins that passively self-align with pre-drilled holes in the bone. The positioning is achieved by the bone structure itself rather than by a heavy mechanical constraint system.
4Manufacturing precision
If a complex bone resection jig is used to ensure accurate resection, then manufacturing precision is improved, but surgical time increases
Solution Approach 1:
The positioning pins are inserted into the bone surface before resection to pre-establish the resection plane. The spacer block is positioned beforehand to define the correct resection interval. This preliminary positioning eliminates the need for complex adjustments during the resection process.
Solution Approach 2:
The positioning pins automatically self-align with pre-drilled holes in the bone, and the spacer block self-positions against the positioning pins. This self-aligning mechanism eliminates the need for complex adjustment procedures by the surgeon, reducing surgical time.
Data Source
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AI summary
A bone resection jig that can make ligament tension equal at extension and flexion positions without any actual measurements when resecting femur and tibia during artificial knee joint replacement surgery. The bone resection jig used in artificial knee joint replacement surgery includes a spacer block (1) comprised of a grip (6), a hollow box (7) that is provided on an other end side of the grip and has a vertical hole (7a) therein, and a reference spacer part (8) that extends out from the hollow box (7) and is adapted be inserted into the resection region between femur and tibia; a reference pin guide (2) which, when the femur and tibia are in the flexion position, is inserted into the vertical hole (7a) of the hollow box, extends on the reference spacer part (8) to the other end side ofthe grip so as to come into contact with a resection plane (FH) of the tip of the distal end of the femur, and is formed with guide holes (9) for guiding reference pins (3) to be installed from a front side into the resection plane (FH) of the tip of the distal end of the femur; and an aiming member (12) which is, after the spacer block (1) has been removed from a space between the femur and tibia leaving the reference pins (3), brought onto the reference pins (3) by being guided thereby, the aiming member being provided with an indicator (14) that indicates a resection plane (FR) at a back of the distal end of the femur when the aiming member (12) comes into contact with the resection plane (FH) of the tip of the distal end of the femur.