title: Hip Morphology Characterization: Implications in Femoroacetabular Impingement in a Chilean Population.
abstract: BACKGROUND
  Femoroacetabular impingement (FAI) is the result of a mechanical conflict in the hip joint, and its diagnosis is based on clinical and radiological parameters. To our knowledge, there are no published studies describing the radiologic characteristics of FAI in Latin American populations.
  
  
  OBJECTIVE
  To describe the radiological features associated with FAI in an asymptomatic Chilean population.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  We prospectively recruited asymptomatic patients with no history or symptoms of hip pathology who underwent abdomen-pelvis computed tomography (CT) for a nonorthopaedic indication. The acetabular and femoral parameters related to FAI were measured.
  
  
  RESULTS
  We studied 101 subjects (202 hips) with a mean age of 36.8 ± 14.4 years. The mean center-edge angle was 39.4° ± 7.2°. The crossover sign was present in 34 cases (33.7%). The mean alpha angle was 49.7° ± 8.3°. Depending on the cut points chosen for FAI-related parameters, between 39.6% and 69.3% of an asymptomatic Chilean population were found to have morphological features related to FAI.
  
  
  CONCLUSIONS
  Our findings suggest that the proposed pathological threshold values in the literature cannot be extrapolated to a Chilean population, and this must be taken into consideration when evaluating Latin American patients with hip pain.
authors.affiliation: Department of Orthopaedic Surgery, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors.forename: Cristián
authors.initials: C
authors.lastname: Barrientos
authors.affiliation: Department of Imaging, Musculoskeletal Radiology Unit, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Diaz
authors.affiliation: Department of Orthopaedic Surgery, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors.forename: Julian
authors.initials: J
authors.lastname: Brañes
authors.affiliation: Department of Orthopaedic Surgery, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors.forename: Felipe
authors.initials: F
authors.lastname: Chaparro
authors.affiliation: Department of Orthopaedic Surgery, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors.forename: Maximiliano
authors.initials: M
authors.lastname: Barahona
authors.affiliation: Department of Imaging, Musculoskeletal Radiology Unit, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Salazar
authors.affiliation: Department of Orthopaedic Surgery, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors.forename: Jaime
authors.initials: J
authors.lastname: Hinzpeter
keywords: computed tomography of hip; femoroacetabular impingement; hip morphological characterization