title: Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement.
abstract: Femoroacetabular impingement secondary to the cam effect is thought to be associated with an insufficient anterior concavity in the sagittal/axial plane of the femoral head-neck junction. Using three-dimensional computed tomography the anterior and posterior concavity of the femoral head-neck junction was assessed in 36 painful non-dysplastic hips (30 patients). The mean age of the symptomatic hips was 40.7 with 13 females and 17 males. Eighteen out of the 36 hips had a pistol grip deformity. Magnetic resonance gadolinium arthrography was performed to assess for labral and cartilage lesions. Alpha and beta angles measuring the anterior and posterior femoral head-neck junction concavities were also determined in 20 asymptomatic hips (12 patients; mean age 37, 5 females and 7 males) using three-dimensional computed tomography. The mean alpha angle for the symptomatic and the control group were: 66.4 versus 43.8 (p=0.001), and for the beta angle 40.2 versus 43.8 (p=0.011), respectively. All but one of the symptomatic hips had a labral tear with 61% of these hips having associated cartilage damage. Three-dimensional computed tomography represents an accurate tool to quantify the femoral head-neck concavity providing a non-invasive assessment of hips at risk of femoroacetabular impingement.
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, 1250 16th Street Suite 745, Santa Monica, CA 90404, USA. pbeaule@laoh.ucla.edu
authors.forename: Paul E
authors.initials: PE
authors.lastname: Beaulé
authors.forename: Edward
authors.initials: E
authors.lastname: Zaragoza
authors.forename: Kambiz
authors.initials: K
authors.lastname: Motamedi
authors.forename: Nathan
authors.initials: N
authors.lastname: Copelan
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Dorey
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging*; D000328:Adult; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging*; D005272:Femur Neck / Q000000981:diagnostic imaging*; D006615:Hip / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007592:Joint Diseases / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed