# The Femoral Neck-Bite Sign: A Radiographic Indicator of Catastrophic Sandwich Liner Failure in Total Hip Arthroplasty

## TL;DR

This case report describes a hip implant failure in a 74-year-old woman, introducing the 'Femoral Neck-Bite Sign' as a radiographic indicator of catastrophic liner failure.

## Contribution

The paper introduces the 'Femoral Neck-Bite Sign' as a novel radiographic indicator for catastrophic sandwich liner failure in hip implants.

## Key findings

- A sandwich liner failure caused extensive femoral neck notching, metallosis, and osteolysis in a 74-year-old woman.
- Revision surgery was performed using a cage, polyethylene cup, ceramic head, and modular cementless stem.
- The Femoral Neck-Bite Sign was identified as a potential indicator of ceramic liner fracture or implant impingement.

## Abstract

In this case report, we present the failure of a sandwich liner resulting in extensive notching of the femoral neck as well as metallosis and osteolysis in a 74-year-old woman. All implants were removed due to large bone defects and a cage was combined with a polyethylene cup, ceramic head, and modular cementless stem. Clinical and radiological follow-ups were conducted at 6 weeks and 6 months postoperatively, showing postoperative patient-reported outcome measures that were marginally inferior to the preoperative status. We discussed that a timely revision surgery was nonetheless warranted in order to prevent further bone loss and systemic toxic metallosis. We introduce the Femoral Neck-Bite Sign, a radiographic finding that may indicate ceramic liner fracture as in this case or implant impingement resulting in femoral notching.