GB1390494A - Endoprosthetic knee joint devices - Google Patents

Abstract

1390494 Prosthetic knee joints NATIONAL RESEARCH DEVELOPMENT CORP 16 March 1972 [7 Jan 1971] 829/71 Heading A5R An implantable prosthetic knee joint comprises a femoral component, for attachment to the natural femur, comprising two interconnected parts each defining a longitudinally convexly curved first bearing surface and a tibial component, for attachment to the natural tibia, comprising two parts each defining a concave second bearing surface, the bearing surfaces being held in engagement in use by natural elements of the knee. The femoral component includes a generally U- shaped channel member I having two transversely spaced ridges 2a, 2b extending around the outer surface of the member. The tibial component (Fig. 8) has one or two generally flat members having elongate concave areas 7 on a major surface thereof to receive the ridges, projections 5, 9 to fix the components to the femur and tibia respectively. The ridge 2a which functions as the lateral condyle extends around the full outer surface of the channel member whereas the ridge 2b which functions as the medial condyle extends only part-way up the arm of the channel member which forms the anterior part of the component. The ridge 2b projects further than the ridge 2a over the portions of the ridges that articulate with the tibial member. The trough 4 defined by the ridges may have a smooth cross-sectional profile at least on the front arm and part of the base of the channel member to accommodate the patella. The region between the ridges may be slotted to allow the passage of cruxiate ligaments which may be retained. A pair of stems 5 extend from the base of the channel member and are used to fix the member to the natural femur. The tibial component has intracondylar blades 9 extending from the base member 6. The space (8) Fig. 10 (not shown) between the concave areas 7 may be slotted or the tibial component may be formed of two flat parts each having a concave area 7 and a blade 9. The femoral component may be fabricated from a metal such as chromecobalt alloy and the tibial component from a plastics material such as high density polyethylene.