Durability Test Method for Patella Implants

Modeling and testing of the patello-femoral joint (PFJ) presents challenges in simulating the appropriate loading and kinematics. Walking is an activity of lower demand for patella performance. Higher demands occur during higher flexion activities such as stair ascending/descending, chair rising, and squatting. High patellofemoral joint reaction forces (PFJR) have been shown to begin around 60° of tibiofemoral flexion and remain high (2.5 × BW to 3.35 × BW) until approximately 110° of tibiofemoral (TF) flexion, at which point contact with soft tissue will tend to off-load the knee joint. Therefore, the flexion range of highest load for the patella is considered to be between 60° and 110° of TF flexion.