GB1395896A - Endoprosthetic knee joint devices - Google Patents

Abstract

1395896 Endoprosthetic knee joints NATIONAL RESEARCH DEVELOPMENT CORP 25 May 1972 [1 June 1971] 18278/71 Heading A5R An endoprosthetic knee joint device has a femoral part 10, Fig. 11, having portions 11, 12 defining respective elongate bearing surfaces of longitudinally convex form, portions 11, 12 being joined by a bridge 13 so that a slot extends between portions 11, 12 from corresponding ends thereof, and a tibial part, Fig. 17, having portions 21, 22 each defining a bearing surface for engaging a said convex bearing surface of the part 10, portions 21, 22 being interconnected by a bridge 23 so that a slot extends between portions 21, 23 from bridge 23 to corresponding edges of portions 21, 22. In use the .bridges are located anteriorly with portions 11, 12, 21, 22 extending posteriorly therefrom and with the natural cruciate ligaments passing through said slots. The convex bearing surfaces are preferably shaped to conform closely to the natural femoral condyles. The bearing surfaces of portions 21, 22 are elongate and of generally dished form longitudintally and laterally, so that one pair of corresponding ends closely conform to the surface shapes of the anterior portions of the natural merisci when the joint is at or near zero flexion, and opposite ends conform to the natural menisii shape when the joint is at or near maximum flexion and the intermediate portions of said bearing surfaces smoothly join said end portions. The bridge 23 is formed as a ridge, and the bridge 13 which is formed as a trough and acts as a bearing surface for the patella. The components may be attached to the natural femur and tibia using acrylic resin or other gap-filling agents or cements, the back surface of the femoral component being provided with pegs 14 and/or webs and the back surface of the tibial component being provided with dovetail grooves 24 and central plateaus 26 to assist such securement. The femoral and tibial components may be made of metal, such as chrome/cobalt alloy, and of plastics material, such as polyethylene, respectively by casting in moulds made by using the natural bones.