In order to further refine the rehabilitation protocols for transverse patellar fractures, this study conducted numerical simulations using Abaqus to model the interaction between a nickel-titanium shape memory alloy patellar tensioner and bone tissue. By subjecting the fractured patella to biomechanical loading, a comprehensive analysis of multiple variations in the mechanical environment of the patellar tensioner, patella, quadriceps muscle tension, and fracture site was systematically conducted. The following conclusions were drawn: Lower degrees of knee flexion result in primarily bending moments on the patellar tensioner, reducing internal fixation stability, while greater degrees of knee flexion lead to primarily tensile forces, increasing internal fixation stability. Within the knee flexion range of 0 to 150 degrees, the maximum quadriceps muscle force ranged from 240 to 670 N, representing a safe working range for the patellar tensioner. The appropriate range for early rehabilitation exercises falls between 60 and 90 degrees of knee flexion, providing a reliable foundation for fracture recovery training.