When performing a radiographic examination of the knee in the lateral position, which statement is correct?

When performing a radiographic examination of the knee in the lateral position, which statement is correct?

• A. The knee is rotated medially so the intercondylar line is parallel to the film.
• B. The knee is extended fully with the medial portion of the knee touching the film.
• C. The knee is rotated laterally so that the intercondylar line is perpendicular to the film.
• D. The knee is rotated to prone position so that the patella is touching the film.

Answer: (C)

In a lateral knee radiograph, the goal is a true lateral view where the femoral condyles are superimposed and the joint spaces are clearly shown. This is best achieved by placing the knee in a true side-lying position with the knee slightly flexed (about 20–30 degrees) and rotated so the intercondylar line—the line between the femoral condyles—is perpendicular to the image receptor. That orientation aligns the knee so the structures inside the joint are accurately demonstrated and the patellofemoral and femorotibial relationships can be assessed. Rotating laterally accomplishes this true lateral alignment; rotating medially would prevent the condyles from being superimposed and distort the view. Extending the knee fully reduces the visibility of the joint spaces and deranges the lateral perspective, while placing the patient prone or having the patella pressed against the film again fails to provide the correct lateral orientation.

In a lateral knee radiograph, the goal is a true lateral view where the femoral condyles are superimposed and the joint spaces are clearly shown. This is best achieved by placing the knee in a true side-lying position with the knee slightly flexed (about 20–30 degrees) and rotated so the intercondylar line—the line between the femoral condyles—is perpendicular to the image receptor. That orientation aligns the knee so the structures inside the joint are accurately demonstrated and the patellofemoral and femorotibial relationships can be assessed.

Rotating laterally accomplishes this true lateral alignment; rotating medially would prevent the condyles from being superimposed and distort the view. Extending the knee fully reduces the visibility of the joint spaces and deranges the lateral perspective, while placing the patient prone or having the patella pressed against the film again fails to provide the correct lateral orientation.