Biomechanical Comparison of A New Stemless Hip Prosthesis with Different Shapes-A Finite Element Analysis

Minimally invasive surgery (MIS) is a trend of surgery in orthopedics. It can not only reduce patients' pain, but also shorten the recovery period after surgery. However, the benefits of MIS for hip replacement are still limited by the design of conventional total hip stem. The conventional femoral stem is not inserted into the femoral canal through the minimal incision easily. This study aimed to design a new prosthesis to fit the MIS as well as to evaluate the biomechanical effect of the new stemless prosthesis. The design of the new hip prostheses preserved the femoral neck to support eh body weight by introducing a stemless femoral implant with two different shapes, "I" and "O". An anti-sliding fixation rod was then implanted through the fossa of great trochanter to the bottom of the implant and constructed a "gamma"-shaped structure. The finite element (FE) model was implemented to analyze the newly design of the hip stemless prostheses and conventional hip stem. The FE model indicated the I-type implant had not only a comparable result with the conventional implant but also a better performance than the O-type implant in terms of femur stress. Therefore, to shorten the recovery period after surgery, the I-type implant was suggested to be used in MIS.