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.