Rates of interlock screw back-out are high with the retrograde femoral nailing advanced system for distal femur fractures

• Published in: European journal of orthopaedic surgery & traumatology Vol. 34; no. 6; pp. 2909 - 2913
• Main Authors: Bhale, Rahul, Campbell, Sean T., Fitzpatrick, Ellen, Soles, Gillian, Lee, Mark, Saiz, Augustine M.
• Format: Journal Article
• Language: English
• Published: Paris Springer Paris 28.05.2024; Springer Nature B.V
• Subjects: Fractures; Medicine; Medicine & Public Health; Original Article; Surgical Orthopedics; Traumatic Surgery; Retrograde femoral nail; Intramedullary nail; Femoral nail; Retrograde femoral nailing advanced; Distal femur fracture
• DOI: 10.1007/s00590-024-04006-5
• ISSN: 1432-1068; 1633-8065

Purpose The retrograde femoral nailing advanced (RFNA) system (DePuy synthes) is a commonly used implant for the fixation of low distal femur and periprosthetic fractures. There is concern that the rate of distal interlock screw back-out may be higher for the RFNA compared to other nails (ON). The purpose of this study was to evaluate the incidence of interlock screw back-out and associated screw removal for RFNA versus ON, along with associated risk factors. Methods A retrospective comparative study of patients who underwent retrograde nailing for a distal femur fracture at an academic level one trauma center was performed. The incidence of distal interlock screw back-out and need for screw removal were compared for RFNA versus a propensity score matched cohort who received other nails. Results One hundred and ten patients underwent retrograde nailing with the RFNA for a distal femur fracture from 2015 to 2022 (average age: 66, BMI: 32, 52.7% smokers, 54.5% female, 61.8%). There was a significantly higher rate of interlock back-out in the RFNA group compared to the ON (27 patients, 24.5% vs 12 patients, 10.9%, p  = 0.01), which occurred 6.3 weeks postoperatively. Screw removal rates for back-out were not significantly different for the RFNA group versus ON (8 patients, 7.3% vs 3 patients, 2.7%, p  = 0.12). Conclusion In this retrospective comparative study of distal femur fractures treated with retrograde nailing, the RFNA implant was associated with an increased risk of distal interlock screw back-out compared to other nails.