Clinical and radiological outcomes of patients treated with the Orthofix Chimaera Long nailing system for proximal and diaphyseal femoral fracture

Abstract

Background Intramedullary long nailing is a popular method to treat femoral shaft or sub-trochanteric fractures. Various complications have been described such as intraoperative anterior cortical perforation of the distal femoral shaft or post-surgical lateral thigh pain. In order to prevent those possible complications, a new intramedullary nailing system (Chimaera, Orthofix®) was designed. This study aims to evaluate the clinical and radiological results after antegrade intramedullary nailing of traumatic femoral shaft and inter-/subtrochantreric fractures.Methods A prospective cohort study was conducted on 20 consecutive patients with AO/OTA type 31A2.3-A3.3 and type 32A-C fractures treated with the Chimaera long nailing system from December 2017 to January 2021 at our level 1 trauma center. Parker & Palmer and Jenson scores were assessed at 3 months and compared to before the surgery. Radiologic assessment consisted in checking the position of the cephalic screw, using the tip-apex distance (TAD) and Cleveland zone. The mean follow-up was 12.5 (1–33) months.Results Parker and Palmer scores were equivalent to before the fracture for 4 patients (31%); minor changes were seen in 6 patients (46%). Jensen score was equivalent or with maximum gain of 1 point for 11 patients (87%) at 3 months. No intra-operative major complication was recorded. The median TAD was 16.4 mm (IQR 14.0-20.2) and lag screw position was in 85% of patients in the Cleveland central zone. Two patients needed revision surgery. Fracture union occurred in all patient.Conclusion The long Chimaera nailing device showed good functional and radiological outcomes.