RESUMEN
OBJECTIVES: To determine the incidence of cut-out, cut-in, cut-through, Z-effect, and reverse Z-effect in two cephalomedullary nail (CMN) systems: one with single cephalic screw fixation and the other with dual-screw fixation using a lag screw and an anti-rotation screw. METHODS: A retrospective study from a cohort of patients was conducted between January 2017 and August 2019 in patients with intertrochanteric fractures treated with osteosynthesis using CMN. RESULTS: One hundred ninety-six patients with intertrochanteric fractures who met the inclusion criteria were recruited. The median age was 81 years [interquartile range (IQR) 12]. Seventy-six percent had fractures classified as Orthopaedic Trauma Association/Arbeitsgemeinschaft für Osteosynthesefragen (OTA/AO) 31A2. Twenty-one mechanical complications occurred, 8.7% (17) was cut-out with a single cephalic screw CMN and 2% (4) was Z-effect with a dual-screw CMN non-integrated. The median tip-apex distance (TAD) was 19.4 mm (IQR 10.8) in patients who experienced cut-out and 19 mm (IQR 10) in those who experienced Z-effect. The median time to cut-out occurrence was 39,5 days (IQR 47,5), while the median time to Z-effect was 90 days (IQR 86). CONCLUSIONS: The incidence of osteosynthesis failure using CMN is more frequent in patients treated with a single cephalic screw CMN. LEVEL OF EVIDENCE: Therapeutic, Level III.