Patent ID: 7470288
Filing Date: 2008-12-30
Classification: A61B,A61F

Abstract:
1. In a telemetric knee prosthesis adapted to measure forces transmitted across the knee joint, the knee prosthesis having a femoral component, a tibial bearing member in articulating contact with the femoral component, a tibia engaging member and a tibial tray engaged to the tibial bearing member and the tibia engaging member, the tibial tray comprising: an upper plate having a portion configured for engaging the tibial bearing member; a lower plate having a portion configured for engaging the tibia engaging member, said lower plate spaced apart from said upper plate and defining a plurality of cavities opening away from said upper plate, each of said cavities including a diaphragm adapted to flex when subjected to a load normal to the diaphragm; a plurality of support posts, each connected between said upper plate and said diaphragm of a corresponding one of said plurality of cavities, wherein said support posts are circular in cross-section and have a diameter that is about ⅓ the diameter of the corresponding one of said plurality of cavities; and a force sensing element disposed within each of said plurality of cavities and operable to produce an output signal in response to flexing of said diaphragm.