Finite element study on knee injuries in the parachute landing

Objective: To numerically simulate the half-squat parachute landing and analyze the mechanism of knee injuries with the finite element method based on the data of the simulated parachute landing experiment. Method: The half-squat parachuting experiment was performed by 16 healthy volunteers. The heights of simulated landing were 0.32 m, 0.52 m and 0.72 m respectively. A three-dimensional finite element model of human knee joint was developed based on magnetic resonance images. The kinematical data of the knee and the data of the reaction force obtained by experiments were used to make a numerical simulation of the parachute landing process. Results: The stress level of the knee increased with the increase of the height. The lateral meniscus and cartilage suffered greater loads than the medial ones. Obvious stress concentrations occurred in the anterior cruciate ligament and the medial collateral ligament when the knee flexion degree reached the peak value. Conclusions: The severe impact in parachute landing is the direct cause of injuries in parachute landing. The lateral cartilage and meniscus are more likely to be injured, and the anterior cruciate ligament and the medial collateral ligament are easier to tear when the knee flexion degree reaches the peak value.