Background: The elbow joint is stabilized by complex interactions between bony structures and soft tissues, notably the lateral and medial collateral ligaments. Posterolateral rotatory instability (PLRI), a form of elbow instability, is challenging to diagnose due to overlapping symptoms with other conditions. The radiocapitellar line (RCL) is a radiographic tool for assessing humeroradial alignment and elbow stability, but its diagnostic accuracy remains debated. This study aims to …