Risk factors for revisions in patients following total hip arthroplasty and hemiarthroplasty due to femoral neck fractures

BACKGROUND: Total hip arthroplasty (THA) and hemiarthroplasty (HA) are established treatments for displaced femoral neck fractures (FNF), yet factors associated with revision following either procedure remain poorly defined. This study evaluated demographic, clinical, and laboratory predictors of revision after THA and HA for FNF. METHODS: A retrospective cohort study was conducted at a tertiary trauma centre including 2,522 patients treated with arthroplasty for FNF (885 THA, 1,637 HA). Demographic characteristics, comorbidities, and pre- and postoperative laboratory parameters were compared between patients who underwent revision and those who did not. Variables significant on univariate analysis were entered into multivariable logistic regression. Receiver operating characteristic (ROC) analysis was performed to determine optimal cutoff values for significant continuous predictors. RESULTS: Revision occurred in 93 of 885 THA patients (10.5%) and 43 of 1,637 HA patients (2.6%) (p < 0.001). In the THA cohort, patients requiring revision were younger (65.4 vs. 72.5 years, p < 0.001), had shorter hospital stays (5.4 vs. 7.5 days, p = 0.001), higher postoperative haemoglobin (10.5 vs. 9.6 g/dL, p < 0.001), and lower postoperative C-reactive protein (CRP) levels (10.8 vs. 15.7 mg/dL, p = 0.007). Multivariable analysis identified younger age (OR 0.94 per year, 95% CI 0.91-0.98; p = 0.003), higher postoperative haemoglobin (OR 1.29, 95% CI 1.01-1.66; p = 0.044), and lower postoperative CRP (OR 0.94, 95% CI 0.90-0.99; p = 0.029) as independent predictors of revision. ROC analysis identified age < 60 years (AUC 0.66) and postoperative haemoglobin ≥ 10.55 g/dL (AUC 0.63) as optimal thresholds. In the HA cohort, only postoperative lymphocyte count differed significantly between revision and non-revision groups, precluding multivariable analysis. CONCLUSIONS: Revision following arthroplasty for femoral neck fracture was substantially more common after THA than HA. Among THA patients, revision was associated with younger age and markers of better postoperative physiological recovery rather than medical frailty. These findings suggest that revision risk after fracture-related THA may largely reflect the greater activity level and longer survivorship of healthier patients, information that may assist preoperative counseling and individualized procedure selection.