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Comparative Study
. 2025 Oct 1;39(10):564-571.
doi: 10.1097/BOT.0000000000003043.

Distal Interlocking Screw Backout in New-Generation Retrograde Femoral Nails

Adam N Musick  1   2 , Robert K Wagner  1   2 , Kameron M Kraus  3 , Wyatt G S Southall  3 , Austin T Gregg  1   2 , Thomas J Policicchio  1   2 , Maaz Muhammad  1   2 , Stephen T Duncan  4 , David C Landy  5 , Arun Aneja  1   2
Affiliations
Comparative Study

Distal Interlocking Screw Backout in New-Generation Retrograde Femoral Nails

Adam N Musick et al. J Orthop Trauma. .

Abstract

Objectives: To compare distal interlocking screw backout rates between 2 new-generation retrograde femoral nails: the DePuy Synthes RFN-Advanced Retrograde Femoral Nail (RFNA) and the Stryker T2 Alpha Femur Retrograde Nail (T2 Alpha).

Design: Retrospective comparative study.

Setting: Three Level 1 trauma centers.

Patient selection criteria: Patients aged ≥18 years who underwent operative fixation with the RFNA or T2 Alpha for a diaphyseal or distal femur fracture [Orthopaedic Trauma Association/Arbeitsgemeinschaft für Osteosynthesefragen (OTA/AO) 32-33] between November 2022 and August 2024 with a minimum follow-up of 3 months.

Outcome measures and comparisons: The primary outcome was the distal interlocking screw backout rate. Secondary outcomes included time to backout and reoperation rates for screw removal. Outcomes were compared between the RFNA and T2 Alpha.

Results: A total of 103 patients [median age 59 years (IQR: 38-73), 61% women] were included, comprising 63 OTA/AO 32 and 40 OTA/AO 33 fractures, with 24 treated with the RFNA and 79 with the T2 Alpha. Backout rates were higher in the RFNA group [38% (95% CI: 20%-59%) vs. 5.1% (95% CI: 1.6%-13%), P < 0.001]. Stratified by fracture location, backout rates remained higher in the RFNA group for both diaphyseal [6/20 (30%) vs. 1/43 (2.3%), P = 0.003] and metaphyseal fractures [3/4 (75%) vs. 3/36 (8.3%), P = 0.008]. Time to backout was earlier in the RFNA group [5 weeks (IQR: 3-6) vs. 19 weeks (IQR: 14-31), P = 0.013]. Reoperation rates for screw removal were higher in the RFNA group (21% vs. 0%, P < 0.001). The median follow-up for the overall cohort was 27 weeks (IQR: 18-41).

Conclusions: The RFNA was associated with a higher rate of distal interlocking screw backout, an earlier time to backout, and an increased reoperation rate for screw removal compared with the T2 Alpha. These findings can guide surgeons in implant selection and highlight the need for solutions to mitigate distal interlocking screw backout in the RFNA.

Level of evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Keywords: RFNA; T2 Alpha; distal interlocking screw backout; femur fracture; retrograde femoral nail.

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Conflict of interest statement

A. Aneja reports honoraria from the Arbeitsgemeinschaft fur Osteosynthesefragen Foundation and research support from the Orthopaedic Trauma Association, American Orthopaedic Foot and Ankle Society, and United States Department of Defense. S. T. Duncan receives royalties from Smith and Nephew; is a paid consultant for Smith and Nephew, OrthAlign, and Bone Support; has stock options in MiCare and ROMTech; receives research support from Smith and Nephew; Stryker, Medtronic, and Zimmer/Biomet. R. K. Wagner received support from the Marti-Keuning Eckhardt Foundation (Amsterdam, the Netherlands), the Cultuurfonds (Amsterdam, the Netherlands), the VSB Foundation (Utrecht, the Netherlands), and the Stichting Prof. Michaël-van Vloten Foundation (the Hague, the Netherlands). The remaining authors report no conflict of interest.

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