Clinical outcomes of using contralateral-side laterally bent intramedullary nails in atypical femur fractures with femoral bowing

This study aimed to evaluate the clinical outcomes of using contralateral-side laterally bent intramedullary nails (IMNs) in bowed atypical femur fractures (AFFs). We retrospectively reviewed bowed AFFs treated with contralateral-side laterally bent IMNs. In total, 20 patients with 25 cases of AFFs were included. Surgical outcomes including bone union time, complications, femoral bowing, and leg length discrepancy (LLD) were evaluated. We evaluated the surgical safety of performing contralateral-side intramedullary nailing with its intraoperative and postoperative complications and compared the LLD. The average age was 76.8 years (range 67–86 years), and all of patients were female. There were 10 cases of complete AFFs and 15 cases of incomplete AFFs. Fourteen patients (70%) had a history of bisphosphonate (BP) use with an average of 74.5 months of its use. In the complete AFF cases, reduction of the fractures was tried to restore the patients’ normal anatomical geometry. The average lateral gap was 0.6 mm (0–1 mm), and the average medial gap was 1.6 mm (1–3 mm). All cases achieved bone union without secondary intervention. There were no intraoperative fractures or postoperative complications. The average bone union time was 22.0 weeks and 9.2 weeks in complete and incomplete AFFs, respectively. The average preoperative femoral bowing seen in the coronal and sagittal planes was 10.1° and 16.1°, respectively, while the average postoperative bowing was 6.6° and 11.3°, respectively. The average change of angle was 3.5° in the coronal plane and 4.8° in the sagittal plane. The mean change of LLD was 5.7 mm. The use of contralateral-side laterally bent IMNs in treating bowed femurs showed excellent clinical outcomes without complications. In severely bowed femurs, this technique can be safe and useful.