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

BACKGROUNDDiagnosing minimally displaced femoral PPFs using plain-film radiographs can be challenging. As a result, fractures can be missed. CASE REPORTWe 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. CONCLUSIONPaying attention to the Lucent Line Sign can be pivotal in the diagnosis of minimally displaced PPFs around cemented polished tapered stems.