Patent ID: 8403985

Claim:
A spacer implant for placement between a femoral condyle and a tibial plateau of a knee joint, the knee joint including soft tissue components, the spacer implant comprising: a spacer body sized and shaped to fit within and substantially occupy a single compartment of the knee joint between the femoral condyle of a femur and the tibial plateau of a tibia, the single compartment of the knee joint extending in a lateral-medial direction from a position near an outermost point of the femoral condyle to a position near an intercondylar notch of the femur and extending in an anterior-posterior direction from a position near an anterior-most point of the femoral condyle to a position near a posterior-most point of the femoral condyle, the spacer body being defined by a femoral concave bearing surface, a tibial bearing surface opposite the femoral concave bearing surface, and an outer periphery extending about the spacer body between the femoral concave and tibial bearing surfaces; and at least one tether extending transversely relative to the spacer body, the at least one tether having a first end coupled to the outer periphery of the spacer body between the femoral concave and tibial bearing surfaces and a second end extending outwardly from the outer periphery of the spacer body to one of a first location above the femoral concave and tibial bearing surfaces for attachment to an outer surface of the femur and a second location below the femoral concave and tibial bearing surfaces for attachment to an outer surface of the tibia wherein the spacer body is formed of a plurality of layers, the plurality of layers including an exterior layer and a core layer, wherein the exterior layer and the core layer have different material properties such that the core layer is greater in strength than the exterior layer.