From Valgus-impacted to Displaced: Clinical and Technical Lessons in Femoral Neck Fracture Fixation with the Femoral Neck System.

Introduction: Femoral neck fractures continue to challenge orthopedic surgeons due to their complex biomechanics, high shear stresses, and risk of avascular necrosis (AVN) or non-union. The Femoral Neck System (FNS) is a relatively newer fixed-angle device designed to enhance stability while minimizing soft-tissue damage. This case series presents our clinical experience with the FNS across a spectrum of femoral neck fractures, focusing on technical nuances and lessons that influenced our patients' outcomes. Case Series: Eight patients (aged 24-66 years) with femoral neck fractures of varying Garden and Pauwel types were managed with the FNS. Fracture patterns ranged from stable valgus-impacted to high-energy displaced fractures, including cases with concomitant pelvic or shaft injuries. Stable, valgus-impacted fractures treated with in situ fixation and minimal compression consistently achieved union and excellent function by 3 months. Displaced and vertical fractures united reliably when near-anatomical or valgus reduction with central implant placement and bi-cortical distal fixation was achieved. Technical errors such as anterior or eccentric bolt placement, unicortical distal locking, or correction of valgus to neutral alignment were associated with complications including varus collapse, implant back out, and neck shortening. One young patient developed AVN following high-energy trauma despite satisfactory fixation. Conclusion: The FNS offers a stable and minimally invasive option for femoral neck fracture fixation when applied with precise technique and respect for fracture morphology in selected cases. In situ or slight valgus fixation, especially in osteoporotic bone, yields superior outcomes due to the FNS's invasive nature, avoidance of rotational torque to the at-risk head fragment and retention of the inherently stable valgus or neutral alignment. Complications were largely attributable to mechanical and technical factors rather than implant design, highlighting the importance of meticulous surgical planning and execution and careful patient selection.