Total Hip Arthroplasty in Hip Osteoarthritis with Subtrochanteric Localized Periosteal Thickening: Preoperative Planning Using Finite Element Analysis to Determine the Optimal Stem Length

Background: Owing to the risk of atypical femoral fractures, total hip arthroplasty presents unique challenges for patients with ipsilateral osteoarthritis and localized periosteal thickening in the femoral subtrochanteric region. Stem length selection is critical for minimizing stress concentration in the thickened cortex to avoid such fractures. Herein, we report the case of a 78-year-old woman with ipsilateral hip osteoarthritis and localized subtrochanteric periosteal thickening. Methods: Preoperative planning included a finite element analysis to assess the stress distribution across various stem lengths. A simulation was conducted to determine the optimal stem length to span the cortical thickening and reduce the risk of postoperative complications. Results: The finite element analysis indicated that a stem length of >150 mm was required to effectively reduce the stress at the site of cortical thickening. A 175 mm stem was selected for total hip arthroplasty, which provided a favorable stress distribution and avoided the risk of stress concentration. Conclusions: In cases of ipsilateral osteoarthritis with localized subtrochanteric periosteal thickening, finite element analysis can be valuable for preoperative planning to determine the optimal stem length, thereby reducing the risk of atypical femoral fractures. Further studies with multiple cases are recommended to validate these findings and improve surgical outcomes.