Final answer:
The radiographic indicator of a lateral meniscus tear in the setting of tibial plateau is the presence of joint effusion or fluid in the knee joint.
Step-by-step explanation:
The radiographic indicator of a lateral meniscus tear in the setting of tibial plateau is the presence of joint effusion or fluid in the knee joint. When the lateral meniscus is torn, it can lead to increased movement of fluid within the joint, causing swelling and fluid accumulation. This can be seen on radiographic imaging, such as an X-ray or MRI, where the presence of joint effusion indicates a possible lateral meniscus tear.