Mind the gap! The Lucent Line Sign: A Pathognomonic Radiographic Finding in Periprosthetic Hip Fractures Around Cemented Polished Tapered Femoral Stems

Introduction: Diagnosing minimally displaced femoral PPFs using plain-film radiographs can be challenging. As a result, fractures can be missed. Case Report: We present four cases of minimally displaced PPFs around cemented polished tapered stems. In each case, radiographs demonstrate no clear cortical breach, but the presence of a fracture is highlighted by a pathognomic lucent line between the cement mantle and the prosthesis: The Lucent Line Sign. Conclusion: Paying attention to the Lucent Line Sign can be pivotal in the diagnosis of minimally displaced PPFs around cemented polished tapered stems. Keywords: Periprosthetic fracture, hip fracture, femoral fracture, taper-slip stem, polished-tapered stem, radiographs.