Fig. 4A–B

(A) The false profile view of the left hip of a 37-year old female patient with bilateral protrusion who complained of worsening symptoms and loss of extension on the left side is shown. While the superior joint space is preserved, there is marked joint space narrowing in the posteroinferior aspect of the joint. A prominent ossification of the inferior rim is visible, indicating posteroinferior impingement. (B) Computer tomography revealed that the area of cartilage destruction and subchondral cyst formation in the posteroinferior joint is even more extensive than on the false profile view. A large bone apposition of the inferior rim can be seen, explaining the impingement and loss of extension.