Sindrome do impacto femoro-acetabular

Tannast et al. Femoroacetabular Impingement

M u s c ul o s kel et a l I m ag i n g • R ev i ew

Femoroacetabular Impingement: Radiographic Diagnosis—What the Radiologist Should Know
Moritz Tannast1 Klaus A. Siebenrock1 Suzanne E. Anderson2,3
Tannast M, Siebenrock KA, Anderson SE OBJECTIVE. The purpose of this article is to show the important radiographic criteria that indicate the two types of femoroacetabular impingement: pincer and cam impingement. In addition, potential pitfalls in pelvic imaging concerning femoroacetabular impingement are shown. CONCLUSION. Femoroacetabular impingement is a major cause for early “primary” osteoarthritis of the hip. It can easily be recognized on conventional radiographs of the pelvis and the proximal femur. emoroacetabular impingement (previously also called “acetabular rim syndrome” [1] or “cervicoacetabular impingement” [2]) is a major cause of early osteoarthritis of the hip, especially in young and active patients [3–6]. It is characterized by an early pathologic contact during hip joint motion between skeletal prominences of the acetabulum and the femur that limits the physiologic hip range of motion, typically flexion and internal rotation. Depending on clinical and radiographic findings, two types of impingement are distinguished (Fig. 1): Pincer impingement is the acetabular cause of femoroacetabular impingement and is characterized by focal or general overcoverage of the femoral head. Cam impingement is the femoral cause of femoroacetabular impingement and is due to an aspherical portion of the femoral head–neck junction (Fig. 2). Most patients (86%) have a combination of both forms of impingement, which is called “mixed pincer and cam impingement,” with only a minority (14%) having the pure femoroacetabular impingement forms of either cam or pincer impingement [7]. During sports activities and activities of daily living, repetitive microtrauma of these osseous convexities occur. As a consequence of this