Relationships between Femoral Offset Change and Clinical Score following Bipolar Hip Arthroplasty in Femoral Neck Fractures

Purpose This study aimed to investigate the relationship between femoral offset (FO) and clinical outcomes of patients with femoral neck fracture following bipolar hip arthroplasty (BHA). Materials and methods Records for a total of 520 patients who underwent BHA for a femoral neck fracture between December 1, 2003, and September 30, 2018, were reviewed retrospectively. Patients with unclear medical records, a congenital deformity and preoperative trauma history of the hip, high-energy multiple trauma, or a history of neurodegenerative disease or cerebrovascular disease were excluded. The remaining 77 patients included in the analysis had a minimum follow-up period of one year. For clinical assessment, the postoperative pain visual analogue scale (VAS) and Harris hip score (HHS) were analyzed at each follow-up period. For radiological assessment, the difference in leg length discrepancy (LLD) and FO were measured. Results The difference in mean FO postoperatively was 6.7±4.8 mm, and the difference in mean postoperative LLD was 4.9±3.4 mm. The mean HHS was 77.1±7.7, 82.3±8.6, 83.4±7.7, and 86.4±6.7 at 1, 3, 6, and 12 months postoperative, respectively. The correlation coefficient between FO and HHS in 1-year follow-up was -0.38, and a statistically significant outcome was found (P=0.001). For the HHS domain, the correlation coefficient for function at 1-year follow-up was -0.42, revealing a statistically significant outcome (P=0.0001). Conclusion There was a statistically significant correlation between clinical outcomes and FO difference at 1 year after BHA in patients over 65 years of age with femoral neck fractures.