Periprosthetic femoral fractures are the third most reason for reoperation after the total hip arthroplasty with an incident rate of approximately 6%. The Vancouver type B periprosthetic femoral fractures account for over 70% of all cases, while the sub-type B1 fracture (when the total hip stem is stable) has remained a clinical challenge due to incidences of severe complications after the standard plate-screw fixation. To seek biomechanically sound fixations for the Vancouver type B1 fracture, this dissertation developed a combined modeling and testing framework to investigate the efficacy of fixation for a Vancouver type B1 fracture using different construct lengths and different plating systems. Specifically, the coupled musculoskeletal and finite element model of total hip stem and plate implanted femurs were developed to simulate the physiological bone strain and the plate stress under loads of common activities of daily living. The modeling results were shown to be able to effectively evaluate and compare the mechanics of different plating systems and construct lengths but were also able to shed light on the mechanisms of mechanical pathogenesis of PFFs. The models also showed good fidelity in predictions of bone strain and bone remodeling stimuli as compared with the previous clinical and biomechanical studies. The results of the coupled models were used as a basis for developing several new mechanical tests, which were shown to match the simulated physiological bone strain and plate stress in the coupled musculoskeletal and finite element models.