Prevalence of Cam Deformity with Associated Femoroacetabular Impingement Syndrome in Hip Joint Computed Tomography of Asymptomatic Adults

Abstract

PurposeFemoroacetabular impingement (FAI) is considered an important cause of early degenerative arthritis development. Although three-dimensional (3D) imaging such as computed tomography (CT) and magnetic resonance imaging are considered precise imaging modalities for 3D morphology of FAI, they are associated with several limitations when used in out-patient clinics. The paucity of FAI morphologic data in Koreans makes it difficult to select the most effective radiographical method when screening for general orthopedic problems. We postulate that there might be an individual variation in the distribution of cam deformity in the asymptomatic Korean population.Materials and MethodsFrom January 2011 to December 2015, CT images of the hips of 100 subjects without any history of hip joint ailments were evaluated. A computer program which generates 3D models from CT scans was used to provide sectional images which cross the central axis of the femoral head and neck. Alpha angles were measured in each sectional images. Alpha angles above 55° were regarded as cam deformity.ResultsThe mean alpha angle was 43.5°, range 34.7–56.1°(3 o'clock); 51.24°, range 39.5–58.8°(2 o'clock); 52.45°, range 43.3–65.5°(1 o'clock); 44.09°, range 36.8–49.8°(12 o'clock); 40.71, range 33.5–45.8°(11 o'clock); and 39.21°, range 34.1–44.6°(10 o'clock). Alpha angle in 1 and 2 o'clock was significantly larger than other locations (P<0.01). The prevalence of cam deformity was 18.0% and 19.0% in 1 and 2 o'clock, respectively.ConclusionCam deformity of FAI was observed in 31% of asymptomatic hips. The most common region of cam deformity was antero-superior area of femoral head-neck junction (1 and 2 o'clock).

Prevalence of Morphological Variations Associated With Femoroacetabular Impingement According to Age and Sex: A Study of 1878 Asymptomatic Hips in Nonprofessional Athletes

“…16 However, that study did not perform subgroup analysis by age or sex. 6,16,29 Previous studies have suggested that the cam variant is an acquired phenomenon, particularly in men during the second growth spurt, and that it is highly influenced by exercise-related loads applied to the hip during this phase. 55 The 3 radiographic signs of cam-type FAI demonstrated a constant prevalence across age and sex, resulting in no significant differences in sex.…”

Hip and Groin Pain in Soccer Players

“…This is caused by repetitive impact of the proximal portion of the femoral neck against the acetabular labrum and its adjacent cartilage. 54 Two types of femoroacetabular impingement can be distinguished the cam and pincer one. 54 These two types of FAI can occur as separate entities, but it has recently been shown that combined impingement occurs in the majority of cases (86%).…”

“…54 Two types of femoroacetabular impingement can be distinguished the cam and pincer one. 54 These two types of FAI can occur as separate entities, but it has recently been shown that combined impingement occurs in the majority of cases (86%). 54 In case the chondral injury results from cam-type impingement, this is more severe than those which result from pincer type.…”

“…54 These two types of FAI can occur as separate entities, but it has recently been shown that combined impingement occurs in the majority of cases (86%). 54 In case the chondral injury results from cam-type impingement, this is more severe than those which result from pincer type. 56 Pincer-type impingement involves an abnormal morphology of the acetabulum which causes an impingement of the labrum between the femoral neck and acetabulum.…”

“…33,53 Risk factors for an impingement are activities with a high range of motion of the hip or an abnormal anatomic configuration of the hip. 54 Structural deformities of the hip often limit the activity of soccer players. 55 The cam-type femoroacetabular impingement deformity occurs frequently in young male soccer players.…”