Fixed single-condyle prosthesis with different sagittal plane forms

Abstract

The invention relates to the field of medical instrument design, in particular to a fixed unicompartmental prosthesis with different sagittal plane forms, the sagittal plane forms comprise a straight plane with the curvature radius being REF, a buckling plane with the curvature radius being RFF and a rear angle plane with the curvature radius being RPHF, the REF is larger than the RPHF, the straight plane is tangent to the buckling plane, the buckling plane is tangent to the rear angle plane, and the RPHF is larger than the REF. A transition arc section ALEF from the farthest point of the curvature radius of the unbent surface to the tangent point of the unbent surface and the buckling surface and a transition arc section ALFF from the tangent point of the unbent surface and the buckling surface to the last point of the buckling surface are arranged, and different sagittal plane forms are achieved when the fixed unicondylar prosthesis is used for replacing the thighbone inner side compartment or the thighbone outer side compartment. The product provided by the invention enables the sagittal plane of the femoral condyle prosthesis to be more adaptive to the physiological knee joint shape, avoids the instability of the semi-flexion position of the knee joint, and realizes the accurate ligament tension balance in the whole course of the knee joint movement after the unicompartmental knee arthroplasty, thereby reducing the postoperative complications.

Description

technical field [0001] The invention relates to the field of medical device design, in particular to a fixed unicondyle prosthesis with different sagittal plane shapes. Background technique [0002] Currently, the existing fixed unicompartmental prostheses on the market can be applied to both the medial and lateral compartments of the femur, but their sagittal plane shapes are consistent. In clinical practice, the normal physiological and anatomical structures of the medial and lateral compartments of the femoral condyle are different, which will lead to the inconsistency between the sagittal plane of the femoral condyle prosthesis and the physiological anatomy of the femoral condyle. In addition, clinically, the flexion-extension balance is only performed on the fixed unicondyle in the position of extension and flexion of 90 degrees. This will lead to over-packing or under-packing in the semi-flexion position of the knee joint after unicompartmental replacement, resulting ...

AI Technical Summary

Problems solved by technology

If the knee joint is overpacked after unicompartmental replacement, it will cause a cam effect during moderate knee flexion. When the knee joint is flexed, the ligaments will first tighten and then suddenly relax, which will greatly increase the wear of the tibial plateau pad of the knee joint.

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