Fluoroscopic demonstration of femoroacetabular impingement during hip arthroscopy.

Femoroacetabular impingement is a cause of hip pain that in selected cases can be treated by removal of impinging bone (osteoplasty). No absolute parameters for osteoplasty exist. We present a technique for dynamic evaluation of bony impingement and control of arthroscopic osteoplasty using intraoperative fluoroscopy. With the patient supine on a fracture table, the C-arm is positioned between the legs. Femoral anteversion is measured with the C-arm vertical and the hip flexed 90° (Dunn view). The C-arm is then tilted back 25° from vertical to create a profile view of the anterior rim, and the hip is flexed under fluoroscopy to find the location of maximum head/neck deformity. Because the distance between rim and neck is apparent, a spot view in that position is used to plan the osteoplasties. Impingement is demonstrated by forced internal rotation and is obvious as bony contact, movement of the pelvis, or joint subluxation. Osteoplasty of the neck is performed with the hip extended and the C-arm tilted to reproduce the view of the maximum neck deformity. The dynamic examination is repeated to confirm adequacy of the osteoplasty and improvement in internal rotation. Hip deformities could be efficiently identified and individually corrected.