Radiographic featuresįor initial evaluation of the acetabulum plain radiographs of the pelvis are recommended and an additional view of the femoral neck such as Dunn views, cross-table lateral, frog-leg lateral or Meyer lateral for the assessment of the femoral head-neck junction 2.Ĭross-sectional imaging is advised for better characterization, the detection of chondral and labral lesions and preoperative planning 2,3. Chondral contrecoup lesions in the case of pincer morphology are often found posteroinferiorly 1. Labral injuries and tears are most frequently located at the most prominent site of cam and/or pincer morphology, which is most frequently at the anterosuperior portion of the acetabular rim. The morphological change in cam morphology is situated at the femoral head-neck junction, most often in the anterosuperior position lateral to the physeal scar with decreased femoral head-neck offset 1,3.Īcetabular over-coverage in pincer morphology can be global or focal and concerns the acetabular rim, focal acetabular overcoverage can be anywhere but most often is also located anterosuperior due to acetabular retroversion, posterior wall prominence and os acetabuli being other forms of focal overcoverage 1. Mixed type: a combination of the two morphologies Pincer type: focal or global acetabular over-coverage can lead to labral compression and chondral wear at the site of impingement also frequently anterosuperiorly with concomitant chondral injury posteroinferiorly as a contrecoup lesion as a long-term sequel Two basic structural factors or subtypes of the femoroacetabular morphology have been identified, which can lead to femoroacetabular impingement either alone or in combination:Ĭam-type: the loss of sphericity leads to shear forces at the chondrolabral junction during hip flexion and internal rotation which can then lead to chondrolabral separation and chondral delamination typically in the anterosuperior aspect of the acetabulum 2 The etiology of cam and pincer morphology comprises primary (idiopathic) and secondary (developmental, traumatic and iatrogenic) causes 3. Pathologyįemoroacetabular impingement is an intra-articular or internal form of impingement, where structural changes combined with dynamic factors as repetitive abnormal contact of the acetabulum and the femoral head-neck junction lead to mechanical stress and shear forces on the labrum and chondral surfaces and subsequent damage 1-4. Sometimes the pain is also described in the buttock, back or thigh and in addition, there may be symptoms of stiffness, clicking, locking, catching 2.Ī common clinical test for femoroacetabular impingement is the FADIR (flexion, adduction, internal rotation) test, which is sensitive but not specific 2. a painfully restricted range of motion during hip flexion, internal rotation and adduction.

Patients usually present with motion or position-related hip and/or groin pain e.g. Given the widespread prevalence of cam and/or pincer morphology in the asymptomatic population, the diagnosis of femoroacetabular impingement syndrome is reliant on positive symptoms and clinical examination signs in addition to imaging findings of a femoroacetabular impingement morphology 24. Previous slipped capital femoral epiphysis or Perthes disease High impact sport activity, especially in adolescence during physeal closure Femoroacetabular impingement is common in active young and middle-aged adult individuals, with pincer morphology being more common in middle-aged women and cam morphology more common in young men 1,2.

Hip joint xray normal