Does the femoral neck system provide better outcomes compared to cannulated screws fixation for the management of femoral neck fracture in young adults? A systematic review of literature and meta-analysis

Background: Management of neck of femur fractures depend upon the age of presentation and it ranges from internal fixation to arthroplasty. In a relatively young population, anatomical reduction with stable internal fixation is the preferred treatment modality; the choice of implants available are multiple cannulated cancellous screws, dynamic hip screws, and the newly devised femoral neck system. The fracture configuration and pattern dictate the ideal implant to be utilized, with the femoral neck system documented to be apt for all the fracture types, while the cannulated screws are deemed better for stable fractures. Methods: A primary electronic search was conducted on databases of Medline, Scopus, Scopus, Cochrane Library, and Embase, to look for articles published between 1st January 2010 to 22nd November 2021. Studies including adults with femoral neck fractures treated with internal fixation with femoral neck system and comparing them with internal fixation with cannulated cancellous screws in terms of variables like mean surgical duration, loss of blood, length of incision, fluoroscopy time, duration of hospital stay and outcomes like union time, complications, functional outcomes, Visual Analogue Score, and femoral neck shortening, were included. Results: 6 retrospective studies with 371 patients (224 males,147 females) (164: FNS; 207: CCS) were included. Our analysis demonstrated no statistically significant difference in terms of duration of surgery, incision length, and length of hospital stay, there was more blood loss in FNS, but less fluoroscopy time. The fracture union time was lesser for the FNS group and also the femoral shortening was lesser in it. There was no difference in terms of complications, pain relief, and functional outcomes. Conclusion: Femoral neck system is a new and effective implant for femoral neck fractures in the young with faster union rates and lesser neck shortening through an incision similar to the conventional multiple cancellous screws. It has additional advantages of lesser fluoroscopy exposure to the patient and the OT personnel. However, the rates of complications like implant failure, non-unions, and avascular necrosis are similar to the cannulated screws and either of the implants do not offer any advantage in the final functional status and pain relief to the patient over each other.