Knee joint prosthesis
OwnerJosef Grafingerinventor
Life of this patent
Estimating the term…
Abstract
The invention relates to a knee joint prosthesis comprising two arched guiding elements (3, 4) with a variable curvature in a first body (1) associated with the thigh, bolts (6, 7), or the like, of a second body (2) associated with the lower leg engaging in said guiding elements. The points XP(φ), YP(φ) of one guiding element (3) and the points XQ(φ) and YQ(φ) of the other guiding element (4) correspond approximately to the following equations: XP(φ)=A1×φ5+B1×φ4+C1×φ3+D1×φ2+E1×φ−F1; YP(φ)=A2×φ5+B2×φ4+C2×φ3+D2×φ2+E2×φ−F2; XQ(φ)=A3×φ5+B3×φ4+C3×φ3+D3×φ2+E3×φ−F3; YQ(φ)=A4×φ5+B4×φ4+C4×φ3+D4×φ2+E4×φ−F3, the deflection angle f of the knee joint being indicated in radians. The inventive knee joint prosthesis enables a significant adaptation to the natural movement.
Claims4
A knee joint prosthesis with a first body associated with the thigh and a second body associated with the lower leg, which engages around the first body in fork fashion, whereby arched guiding elements with a variable curvature are provided in the first body, into which engage bolts of the like of the second body wherein in each of the limbs of the fork-shaped first body two guiding elements with a variable curvature are provided, whereby in each case a bolt or the like of the second body engages into each of the guiding elements, and the points XP(φ), Yp(φ) of the first guiding element and the points XQ(φ), YQ(φ) of the other guiding element correspond approximately to the following equations:
- XP(φ)=A1*φ5+B1*φ4+C1*φ3+D1*φ2+E1*φ−F1
- YP(φ)=A1*φ5+B1*φ4+C1*φ3+D1*φ2+E1*φ−F1
- XQ(φ)=A1*φ5+B1*φ4+C1*φ3+D1*φ2+E1*φ−F1
- YQ(φ)=A1*φ5+B1*φ4+C1*φ3+D1*φ2+E1*φ−F1
- whereby the deflection angle of the knee joint is indicated in radians, the points XP(φ), YP(φ) of the first guiding element and the points XQ(φ), YQ(φ) of the other guiding element corresponding approximately to the following equations:
- XP(φ)=2.5468φ5−13.3577φ4+27.2734φ3−25.0789φ2−14.3902φ−0.0195
- YP(φ)=−2.0355φ5+8.4168φ4−11.4013φ3+0.3239φ2+5.5098φ+0.0201
- XQ(φ)=2.6774φ5−12.9957φ4+21.7884φ3−24.8599φ2+15.9312φ−0.0179
- YQ(φ)=−1.8306φ5+6.7402φ4−10.9995φ3+15.3202φ2+5.5433φ−30.3853
- where the deflection angle φ of the knee joint is indicated in radians.
Dependencies are inferred from the claim text.