First clinical results of 1-year follow-up of the femoral neck system for internal fixation of femoral neck fractures.

Background: Closed reduction and internal fixation (CRIF) is the preferred treatment to retain the native joint and maintain optimal functionality in femoral neck fractures. Sliding hip screw (SHS) and cannulated hip screws (CHS) are established CRIF options. SHS offer high biomechanical stability, whereas CHS are minimally invasive. These established systems have a 17-21% failure rate. The Femoral neck system (FNS) was recently developed to combine the advantages of both predecessors. The aim of this study was to describe the first clinical experience with this novel implant with special emphasis on the safety and efficacy.

Methods: During a 1-year period all patients in our level-2 trauma centre with a FNF indicated for CRIF were treated using the FNS and evaluated at 2, 6, 12 weeks, 6 months and 1 year postoperatively using patient and fracture characteristics, surgical notes and radiographic imaging.

Results: Thirty-four patients were included, mean age was 63 years (SD 8), 58.2% was female. Fractures were classified as Pauwels I (n = 10), Pauwels II (n = 15), Pauwels III (n = 9), Garden I (n = 1), Garden II (n = 17), Garden III (n = 12) and Garden IV (n = 4). Eight reoperations were reported after 1-year follow-up; osteosyntheses failed in 6 patients due to avascular necrosis (n = 4) and cut-out (n = 2). In two patients the implant was removed due to inexplicable pain. Age (< 65 years) was related to lower risk for failure. There was a trend for females having more failures.

Conclusion: This study indicates that the FNS is a potential safe and effective CRIF modality. Age (< 65 years) is an important factor to keep in mind when selecting patients for CRIF as it is related to lower risk for failure. Future long-term follow-up studies with larger populations should indicate if functional results and risk factors for failure are comparable to SHS or CHS.