PROBLEM TO BE SOLVED: To provide an artificial knee joint capable of controlling rotation of a knee joint according to a bending angle and simultaneously securing high stability in the forward and backward directions.SOLUTION: A thighbone component 26 has a medial condyle 21 and a lateral condyle 22. An opening 23 and an elliptic sphere-like sliding part 24 connecting the rear ends of the medial condyle and the lateral condyle and sliding to a tibia plate 10 when the knee joint is bent are formed between the medial condyle and the lateral condyle. The tibia plate includes: an inside fossa for receiving the medial condyle and an outside fossa for receiving the lateral condyle. A spine 13 coming into contact with the elliptic sphere-like sliding part when the knee joint is bent and a recessed sliding surface 14 constituting the rear face of the spine for slidably receiving the elliptic sphere-like sliding part are formed between the inside fossa and the outside fossa, and the elliptic sphere-like sliding part is increased in width continuously from the opening as it goes toward the rear end. The tibia plate is provided with a rear end sliding surface formed to slide the lateral condyle of the thighbone component by chamfering the rear end part of the outside fossa with a flat surface or a curved surface, and the rear end sliding surface is orientated backward to the inside.COPYRIGHT: (C)2014,JPO&INPIT【課題】膝関節の回旋を屈曲角度に応じて制御し、同時に前後方向への高い安定性を確保できる人工膝関節を提供する。【解決手段】大腿骨コンポーネント26が内側顆21と外側顆22とを有し、内側顆と外側顆の間には、開口23と内側顆と外側顆との後端を接続し膝関節屈曲時に脛骨プレート10に対して摺動する楕円球状摺動部24とが形成され、脛骨プレートが、内側顆を受容する内側窩と外側顆を受容する外側窩とを備え、内側窩と外側窩との間には、膝関節屈曲時に楕円球状摺動部に接触するスパイン13と、スパインの後面を構成し楕円球状摺動部を摺動可能に受容する凹状摺動面14とが形成され、楕円球状摺動部の幅が開口から連続して後端に向かって広くなっており、脛骨プレートには、外側窩の後端部を平面又は曲面により面取りすることにより、大腿骨コンポーネントの外側顆を摺動させるための後端摺動面が形成され、後端摺動面が内側後方に方向付けらる。【選択図】図1
