Updated literature review of distal locking techniques for long femoral nails: Advantages and disadvantages.

INTRODUCTION: Distal locking during intramedullary femoral nailing remains a technically demanding and radiation-intensive procedure. Since the last systematic review by Whatling et al., numerous innovations over the past two decades have aimed to improve accuracy, shorten operative time, reduce radiation exposure, and simplify the learning curve. A comprehensive synthesis of available techniques is lacking in the recent literature.

METHODS: A systematic review was conducted, according to PRISMA guidelines, including all studies published between January 2006 and January 2025 that reported on distal locking techniques for femoral intramedullary nails. Five databases (PubMed, Cochrane, Embase, Web of Science, Google Scholar) were screened using predefined keywords. Data were extracted on technique type, associated advantages and disadvantages, operative time, radiation exposure, accuracy, and complication rates. Risk of bias was assessed using RoB 2, ROBINS-I, JBI, NOS, and ROBIS as appropriate. PROSPERO registration: CRD42025626521 RESULTS: Thirty-six studies met the inclusion criteria, covering several categories: fluoroscopy-free techniques, modification of traditional freehand, targeting devices, and navigation-assisted systems (electromagnetic, robotic, optical, laser-guided). Low-tech solutions such as the "nail-over-nail" or auditory-guided techniques demonstrated promising accuracy in low-resource settings but lacked standardization. Meta-analyses confirmed the efficacy of electromagnetic navigation systems, particularly in reducing radiation exposure and operative time, without compromising success rates. Overall, navigation-based systems showed significant reductions in radiation time and promising accuracy across multiple trials.

CONCLUSION: This review highlights the broad spectrum of available distal locking techniques, from conventional approaches to advanced technological solutions. Navigation-assisted systems offer measurable benefits but remain limited by cost and accessibility. Simpler mechanical or acoustic methods remain relevant alternatives in specific contexts. No universal gold standard currently exists that can fully replace "freehand technique". Technique selection should be guided by clinical context, surgeon experience, and available resources. Ultimately, technique adoption will depend on clinical context, available resources, and surgeon familiarity.