Few studies have studied the benefits of custom AM implants for fracture fixations. Proximal humerus fractures are the third most common fractures among elderly population (age 65 and older) and account for 6% of all annually reported fractures, especially common among those who suffer from osteoporosis. Current fixation plates are offered in standard sizes and screw positions which do not address patient’s anatomic variability and loading conditions resulting in severe anatomic reduction (2-3 mm). This original study focuses on proximal humerus fractures using a novel design process that customizes fixation plate and accounts for anisotropic mechanical properties based on AM build orientation. The main objectives are to: (1) develop FEA based design optimization routines for 316L SS produced via L-PBF for proximal humerus fractures and (2) experimentally validate better mechanical stability and compressive fatigue life when compared to conventional fracture fixation plates. Three pairs of fresh-frozen human cadaver shoulders (both left and right upper extremity of the same individuals) are used to: (1) surgically create fractures prior to CT and (2) evaluate fatigue life of AM and conventional plates post-fixation during fatigue testing. This study can be further extended to other common fractures in wrist, clavicle and lower extremity.
- Identify the role of AM build orientation on the fatigue behavior and mechanical stability of fracture fixation plates.
- Understand the significance and ease of achieving better bone-implant countering via metal AM and its impact on both the fatigue life and stability of the fixation plate.
- Identify the need for a systematic design-modeling approach based on patient’s bone density, type and category of fractures and screw positioning to reduce the risk of screw failure.