Failure of the Femoral Neck System in a Young Patient: A Case Report.

Introduction: Femoral neck fractures in young adults are rare but carry a high risk of complications, including non-union and implant failure. The femoral neck system™ (FNS) is a newer fixation device designed to enhance mechanical stability while minimizing surgical morbidity. Limited reports exist on its failure modes. The purpose of this case report is to describe a unique failure of the FNS and the challenges encountered during revision surgery.

Case report: A 21-year-old female sustained a basicervical femoral neck fracture and underwent fixation with the FNS and an additional headless screw at an outside institution. Seven months post-operatively, she developed progressive, atraumatic hip pain and was unable to bear weight. Imaging revealed non-union and implant failure at the aperture where the bolt and antirotation screw exit the plate barrel. Revision surgery included intertrochanteric valgus osteotomy and blade plate fixation. Removal of the broken FNS components was technically demanding and required trephination, leading to further compromise of the femoral head and neck bone stock.

Conclusion: This case highlights a rare failure mode of the FNS involving simultaneous failure of the bolt and antirotation screw at the barrel aperture. Surgeons should be aware of this potential complication and the technical challenges it may pose during implant removal and revision surgery. These considerations may influence implant selection and pre-operative planning, particularly in young patients at risk for non-union.