This excerpt taken from the SMA 10-K filed Feb 27, 2006.
Knees. The knee joint includes the surfaces of three distinct bones: the lower end of the femur, the upper end of the tibia or shin bone, and the patella (knee cap). Cartilage on any of these surfaces can be compromised by disease or injury, leading to pain and inflammation that may require knee reconstruction. Our knee implants include a femoral component, a patella, a tibial tray and an articulating surface (placed on the tibial tray) and are used in total knee reconstruction, partial knee reconstruction and revision procedures. We provide one or more, and in some cases all, of these implants for our customers knee implant systems. We use proprietary manufacturing know-how and advanced computer aided simulation techniques to produce tight tolerance near-net shaped to net shaped tibial implants that require minimal if any machining.