Fig. 2

a X-ray showing an example of a posterolateral polyethylene spinout; there is posterior translation of the tibia on the lateral X-ray and on the anteroposterior (AP) view the lateral side of the joint space is closed down. b X-ray showing an example of a posteromedial polyethylene spinout; there is also posterior translation of the tibia on the lateral X-ray but on the AP view the medial side of the joint space is closed down