Femoral Neck System vs Multiple Screw Fixation in Femoral Neck Fractures
For femoral neck fractures, arthroplasty is strongly recommended over internal fixation for unstable (displaced) fractures, while for stable fractures, the Femoral Neck System (FNS) appears to offer advantages over multiple cannulated screws with faster union rates and less femoral neck shortening, particularly in Pauwels type III fractures. 1, 2
Fracture Classification and Treatment Approach
- Femoral neck fractures are classified as intracapsular or extracapsular, with treatment decisions based on fracture stability, displacement, and patient factors 3
- For unstable/displaced femoral neck fractures, arthroplasty is strongly recommended over internal fixation according to the American Academy of Orthopaedic Surgeons (AAOS) guidelines 1
- In properly selected patients with unstable fractures, total hip arthroplasty may provide functional benefits over hemiarthroplasty, though with increased risk of complications 1
- For stable/non-displaced femoral neck fractures in younger patients, internal fixation is preferred to preserve the native joint 3, 4
Comparison of Internal Fixation Methods
Femoral Neck System (FNS)
- The FNS is a newer implant designed to provide angular stability and resistance to shear forces in femoral neck fractures 5, 2
- FNS demonstrates shorter operative time compared to cannulated screw fixation 2
- Recent multicenter research shows FNS achieves a 90% union rate with mean time to union of 4.4 months 2
- FNS shows particular advantage in Pauwels type III (vertical) fractures with significantly shorter time to union (4.8 months vs 6.8 months) compared to cannulated screws 2
- Less femoral neck shortening is observed with FNS compared to cannulated screws 5
Multiple Cannulated Screws (CS)
- Traditional method using 3 parallel cannulated screws in an inverted triangle configuration 4, 5
- Recent multicenter study shows 83.1% union rate with mean time to union of 5.1 months 2
- Lower union rates (58.8%) in Pauwels type III fractures compared to FNS (75.0%) 2
- Requires less surgical exposure but may provide less stability in unstable fracture patterns 5, 6
Other Fixation Options
- Dynamic hip screw with derotational screw (DHS+DS) provides stronger fixation for vertical femoral neck fractures compared to cannulated screws or proximal femoral locking plates 6
- For intertrochanteric fractures, either sliding hip screws or cephalomedullary devices are recommended for stable patterns, while cephalomedullary devices are preferred for unstable patterns 1, 3
Clinical Considerations and Potential Complications
- Risk factors for early failure with FNS include displaced fractures (Garden III or IV), poor reduction quality, longer tip-apex distance, greater sliding distance, and 1-hole implants 2
- Sliding distance was identified as the most significant risk factor for early FNS failure in multivariate analysis 2
- Both FNS and CS fixation methods show similar complication rates, including implant failure, non-union, and avascular necrosis 5
- Anatomical reduction and stable fixation are critical principles regardless of implant choice 7, 2
Perioperative Management
- Either spinal or general anesthesia is appropriate for hip fracture surgery 1, 3
- Multimodal analgesia incorporating preoperative nerve blocks is strongly recommended 1, 3
- Tranexamic acid administration is recommended to reduce blood loss and transfusion requirements 1, 3
- Interdisciplinary care programs should be implemented to decrease complications and improve outcomes 1, 3
Conclusion
For femoral neck fractures requiring internal fixation (particularly stable fractures in younger patients), the Femoral Neck System appears to offer advantages over multiple cannulated screws, especially for Pauwels type III fractures. However, for unstable/displaced femoral neck fractures in older adults, arthroplasty remains the strongly recommended treatment of choice according to current guidelines.