Risk of peri-implant femoral fracture after cephalomedullary nailing in older patients with trochanteric fractures

Introduction Despite the recent increase in the use of cephalomedullary nails for trochanteric hip fractures, factors that may be associated with peri-implant femoral fracture (PIFF) after cephalomedullary nailing for trochanteric fractures remain unknown. We investigated the factors associated with PIFF after cephalomedullary nailing of trochanteric hip fractures in older patients. Methods A nested case–control study was conducted using a database of patients aged ≥65 years who underwent surgery with cephalomedullary nails for trochanteric fractures caused by low-energy trauma during 2005–2021. The cases were defined as patients who developed PIFF after surgery, while controls were patients who did not develop PIFF and who were followed up for ≥3 years after surgery. Four controls were randomly matched to each case for sex and age. First, potential factors associated with PIFF were compared between cases and controls. Second, multivariable conditional logistic regression analysis was employed to assess factors possibly associated with PIFF, controlling for potential confounding factors. Results Of 1,531 patients who underwent surgery with cephalomedullary nails because of trochanteric fractures, we assessed 34 cases and 136 controls (N = 170; mean age 85.7 ± 7 years; and females, 94%). PIFF was significantly associated with patients having undergone total knee arthroplasty (adjusted odds ratios [95% confidence intervals], 4.41 [1.16–16.8]) and those with AO/OTA classification 31A3 fracture (A3 fracture) (2.3 [1.12–4.76]), after adjusting for potential confounding factors. Conclusions Our results showed that PIFF was more likely to develop among older patients with a clinical history of total knee arthroplasty and A3 fracture. These findings suggest that such patients may require careful follow-up with rigorous assessments after cephalomedullary nailing for trochanteric fractures.