Sex-based differences in neck selectivity in total hip arthroplasty using a modular femoral neck system

Background: Dislocation is a major complication of total hip arthroplasty (THA). The modular femoral neck system has some practical advantages in that it permits adjustment neck version and length, if intraoperative instability is present. Anatomical studies have identified morphological differences in the hip joint between men and women. Although sex-based differences exist in hip morphology, it is unclear whether sex-based differences exist in femoral neck selection when the hip is anatomically reconstructed with THA using a modular femoral neck system. This retrospective study aimed to investigate sex-based differences in femoral neck selectivity in THA using a modular neck system. Hypothesis We hypothesised that sex-based differences exist in neck selectivity in THA using a modular neck system. Patients and Methods Between July 2007 and March 2013, 163 THAs using a modular femoral neck system were performed in 149 patients at Teikyo University Chiba Medical Center. Data on the type of modular neck were retrieved from patient records. Fisher’s exact test was used to investigate sex-based differences in femoral neck selectivity in THA using a modular neck system. Results: Neck selectivity did not significantly differ between men and women. Discussion: This retrospective study on THA with a modular femoral neck system revealed no sex-based difference in neck selectivity; however, more than half of the series used varus or version-controlled neck, indicating that a changeable neck may play a role in preventing postoperative dislocation.