Early Mechanical Dissociation of Helical Blade-Barrel Interface in Proximal Femoral Nail: A Case Report.

INTRODUCTION

Proximal femoral nail (PFN) fixation is widely used for intertrochanteric (IT) fractures; however, implant-related complications remain a concern. While commonly reported failures include cut-out, back-out, and implant breakage, dissociation at the helical blade-barrel interface is extremely rare and poorly described in the literature. To the best of our knowledge, no prior case reports have described this specific mode of failure.

CASE REPORT: A 62-year-old male presented with pain in the left hip region following prior PFN fixation for an IT femur fracture. On evaluation, implant failure in the form of PFN nail breakage was identified. The patient underwent revision with a long PFN and lateral support plate. On post-operative day 21, he developed pain and implant prominence. Radiographs did not demonstrate classical blade back-out or cut-out but showed mechanical disengagement at the blade-barrel interface. Three-dimensional computed tomography confirmed dissociation of the barrel from the helical blade, with the blade remaining in situ within the femoral head. There was no evidence of infection. Revision surgery confirmed mechanical failure at the blade-barrel interface. The blade was replaced, and debridement performed. Microbiological cultures were sterile. The patient had an uneventful recovery.

CONCLUSION

This case highlights a rare and early mechanical failure of PFN involving blade-barrel dissociation. Awareness of this failure mode and early radiological evaluation are essential to prevent complications and guide timely intervention.