Biomechanical Investigation of the Impact of Femoral Stem Size on Stress Distribution in Total Hip Arthroplasty: A Finite Element Analysis Study

Total Hip Arthroplasty (THA) is a commonly performed procedure for treating hip joint damage. Aseptic loosening represents a leading cause of implant failure, and inadequate femoral stem sizing has been implicated in this complication. The primary objective of this study was to explore the influence of stem size on the distribution of stress within the bone and stem. To accomplish this, ten stem models with varying sizes were created, and a biomechanical finite element model of the right femur was developed using CT scans of an adult male patient. The study found that the largest femoral stem size exhibited a 26.5% increase in stress shielding compared to the smallest size. On average, each incremental size change led to a stress increase rate of 1.63%. Furthermore, the stress disparity between the largest and smallest femoral stem sizes at the bone interface was approximately 59.73%, with an average stress increase rate of 4.56% per size. Based on these results, it can be inferred that employing smaller stem sizes may offer advantages in terms of enhancing implant longevity and mitigating the risk of stress shielding-related implant failure. It is crucial for clinicians to consider patient-specific factors when determining the most appropriate stem size, as this decision plays a pivotal role in optimizing outcomes and minimizing complications in THA procedures.