The Outcome of FNS System for Femoral Neck Fracture

Background:
Femoral neck fractures represent approximately 50% of all reported hip fracture cases. While varying treatment modalities exist, the majority of hip fractures are managed surgically, and current surgical options consist of internal fixation or arthroplasty. The new minimal invasive implant FNS (Femoral Neck System) by Synthes was developed for the treatment of femoral neck fractures and was thought to become a replacement for the aged canulated screws fixation method. To our knowledge there is no literature addressing short or long outcomes of this new implant. This study was conducted to investigate the outcome of FNS system.

Patients and Methods:
Data was collected from Shaare Zedek Medical Center (SZMC) electronic data base. Inclusion criteria were patient diagnosed with femoral neck fracture which were treated by FNS system between 01.01.2019-01.05.2021. Patients with unavailable initial or follow up radiographs or evidence of pathological fractures were excluded. Data collected includes demographics, documented major comorbidities (divided to 6 main categories) surgical procedure duration and blood loss estimation, hospitalization duration and reoperation rates. Radiographs were revised and fractures were classified according to Garden and Powel`s classification, reduction of the fracture was graded in a 1-3 scale ( excellent , good and bad using Garden classification as a reference).

Results:
Twenty three patients were included in the cohort, with average age of 64 years, 7 males and 16 females. The average number of comorbidities per patient was 0.82. Seventeen fractures were garden 1/2 and 6 as 3/4. Regarding Powel`s classification 11 patients were graded Powel`s 2,and eight graded Powel`s 3. Operations duration was in average 46.5 minutes, blood loss estimated during the surgery was averaged 110 ml. Quality of reduction was graded excellent in 9 cases, good in 11, and bad in 4. One patient died 30 days after the operation not directly related to operative complications. No readmissions or reoperations related to surgical complications were recorded. No cases of failure of fixation or femoral head avascular necrosis were recorded or evaluated in follow up radiographs. The average follow up time was 5.8 months.

Conclusion/Discussion:
This is one of the first studies to report clinical outcome of patients who were treated by FNS system for femoral neck fractures, larger cohort and longer duration of follow-up are required to strongly prove the efficiency of this system.