Femoral Neck System Versus Total Hip Arthroplasty in the Treatment of Pauwels Type III Unstable Femoral Neck Fractures in Patients Aged 60–70 Years: A Comparative Analysis of Clinical Efficacy and Hip Function

OBJECTIVE: At present, there is no clear clinical consensus on the optimal surgical method for the specific population of patients aged 60-70 years with unstable Pauwels Type III femoral neck fractures. Few studies have investigated the efficacy of the Femoral Neck System (FNS) in hip-preserving treatment for this patient group. Therefore, it is necessary to analyze the safety and efficacy of FNS in treating this population. METHODS: A retrospective analysis with pair matching of 93 patients who received FNS or total hip arthroplasty (THA) for Pauwels type III unstable femoral neck fracture in our hospital between January 2021 and August 2023 was conducted. This study used the inverse probability weighting (IPW) method to balance the baseline covariates between the THA group and the FNS group. The effect of covariate balance was evaluated by calculating the standardized mean difference (SMD). The operation duration, intraoperative blood loss, time to begin weight-bearing, Harris score, and complication rate were compared between the two groups. For Harris hip score, generalized estimation equations (GEE) were used. For continuous outcomes, weighted linear regression was used. All statistical analyses report estimates, standard errors, test statistics, p-values, and 95% confidence intervals (CI), with p < 0.05 indicating statistically significant differences. RESULTS: After inverse probability weighting (IPW), the standardized mean difference (SMD) of all covariates was < 0.1, indicating well-balanced baseline covariates between groups and effective reduction of confounding bias. The THA group had significantly longer operation duration (119.23 ± 4.62 min vs. 69.61 ± 2.23 min; between-group difference: -49.62 min, 95% CI: -59.51~-39.73 min, p < 0.05) and greater intraoperative blood loss (205.20 ± 8.60 mL vs. 80.99 ± 7.36 mL; between-group difference: -124.22 mL, 95% CI: -146.62~-101.82 mL, p < 0.05) than the FNS group, but significantly shorter time to begin weight-bearing (3.12 ± 0.15 d vs. 73.38 ± 1.04 d; between-group difference: 70.26 d, 95% CI: 68.19~72.34 d, p < 0.05). During follow-up, HSS scores increased over time in both groups, but the between-group difference trend varied. Complication rate was 6.5% in THA group vs. 8.5% in FNS group; relative risk: 3.709 (95% CI: 0.53~26.08, p = 0.1877), with no statistical significance. CONCLUSION: For the treatment of Pauwels type III unstable femoral neck fractures in elderly patients aged 60-70 years, FNS can achieve satisfactory joint range of motion and clinical efficacy. Compared with THA, FNS can preserve the normal anatomical structure of the hip joint and has less blood loss and shorter operation time.