This specification covers total knee replacement (TKR) prostheses used to provide functioning articulation by employing femoral and tibial components, allowing a minimum of 110� of flexion to high flexion. Replaceable components of modular designs, for example, tibial articulating surfaces and all components labeled for or capable of being used with cement, regardless of whether the same components can also be used without cement are described. Primary and revision prostheses and also covers fixed and mobile bearing knee designs are discussed. Basic descriptions of material and prosthesis geometry are provided. Additionally, those characteristics determined to be important to in vivo performance of the prosthesis are defined. The prostheses are classified into three kinds according to degree of constraint. The first kind is considered constrained which prevents dislocation of the prosthesis in more than one anatomic plane and consists of either a single, flexible, across-the-joint component or more than one component linked together or affined. The second one is a semiconstrained joint prosthesis which limits translation or rotation, or both, of the prosthesis in one or more planes via the geometry of its articulating surfaces. It has no across-the-joint linkages. The third kind is a nonconstrained joint prosthesis which minimally restricts prosthesis movement in one or more planes. Its components have no across-the-joint linkages. The choice of materials is understood to be a necessary but not sufficient assurance of function of the device made from them. All devices shall be fabricated from materials with adequate mechanical strength and durability, corrosion resistance, and biocompatibility.

1.1 This specification is intended to cover all the widely used generic types of knee replacement prostheses used to provide functioning articulation. This includes total knee replacement (TKR) and unicondylar knee replacement (UKR) prostheses of both fixed and mobile bearing varieties, and for primary or revision surgeries. Although a patellar component may be considered an integral part of a TKR, the detailed description of this component is excluded here since it is provided in Specification F1672.

1.2 Included within the scope of this specification are replaceable components of modular designs, for example, tibial articulating surfaces and all components labeled for, or capable of, being used with cement, regardless of whether the same components can also be used without cement.

1.3 This specification is intended to provide basic descriptions of material and prosthesis geometry. Additionally, those characteristics determined to be important to in vivo performance of the prosthesis are defined. However, compliance with this specification does not itself define a device that will provide adequate clinical performance.

1.4 Excluded from the scope are hemiarthroplasty devices that replace only the femoral or tibial surface, but not both; and patellofemoral prostheses. Also excluded are devices designed for custom applications.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.