X-ray

X-rays of the knee will reveal the bones but not the soft tissues. The surgeon may need to 'interpret' the blank spaces to get information about the menisci or joint cartilage.

Page updated August 2023 by Dr Sheila Strover (Clinical Editor)

A single X-ray of the knee gives limited useful information because of the flat dimension. This A-P view hints at the patella and gives some information about the status of the actual joint but on its own it is of limited value.

X-rays are generally taken in at least three planes - both with the knee straight and with the knee bent:

AP view - anteroposterior
Lateral view
Skyline or Sunrise view

This will allow the clinician to evaluate the bones two or three-dimensionally, and small fractures and other problems may be revealed that were not apparent with a single dimension.

Again less information is obtained if the patient is lying on the X-ray table, compared to standing up weight-bearing. The joint space may appear perfectly normal if the patient is lying down, suggesting that the menisci and joint cartilage are normal and filling the space, but a weight-bearing view may show the joint space to collapse on one side if these structures are damaged or missing.