Risk factors of excessive sliding in elderly patients with intertrochanteric fractures treated with PFNA-II: a retrospective observational study.

Purpose: Excessive sliding of cephalic components of cephalomedullary nails has been established to be significantly associated with the development of mechanical failures and unfavorable results in the surgical treatment of intertrochanteric fractures. This study aims to elucidate the risk factors that contribute to excessive sliding in elderly patients treated with PFNA-II devices for the fixation of intertrochanteric fracture.

Methods: We conducted a retrospective analysis of patients aged 65 and older who presented with intertrochanteric fractures and underwent surgical treatment using PFNA-II devices at a university teaching hospital between January 2020 and December 2021. All patients were subjected to a minimum of one year of follow-up. We collected data on patient demographics, as well as preoperative, perioperative, and postoperative radiographic information, identifying mechanical failures during routine follow-ups. Patients were categorized into an excessive sliding group and a normal sliding group based on the sliding distance, with the optimal cut-off determined by receiver operating characteristic (ROC) curve analysis. Binary logistic regression was employed to identify independent risk factors associated with excessive sliding.

Result: Among the 507 eligible patients, the mean postoperative sliding distance was 4.45 mm (SD, 5.39 mm; range, 0-31.67 mm). The cut-off for excessive sliding was determined as 6.75 mm, with 61 patients (12.0%) classified as hving excessive sliding, of whom 18 (29.5%) experienced mechanical failures. Binary logistic analysis indicated that poor reduction quality (OR = 11.493, 95% CI: 3.386-39.014, P < 0.001), and Subtype P in LAT reduction (OR = 15.621, 95% CI: 5.984-40.779, P < 0.001) were independently associated with excessive sliding distance. Their associations were robust across subgroup analyses.

Conclusions: Poor reduction quality and the Subtype P in LAT reduction were identified as independent risk factors for excessive sliding. It is essential for surgeons to be mindful of these two risk factors during preoperative assessment and intraoperative procedures.