title: Prevalence of cam and pincer-type deformities on hip MRI in an asymptomatic young Swiss female population: a cross-sectional study.
abstract: OBJECTIVE
  Femoroacetabular impingement is proposed to cause early osteoarthritis (OA) in the non-dysplastic hip. We previously reported on the prevalence of femoral deformities in a young asymptomatic male population. The aim of this study was to determine the prevalence of both femoral and acetabular types of impingement in young females.
  
  
  METHODS
  We conducted a population-based cross-sectional study of asymptomatic young females. All participants completed a set of questionnaires and underwent clinical examination of the hip. A random sample was subsequently invited to obtain magnetic resonance images (MRI) of the hip. All MRIs were read for cam-type deformities, increased acetabular depths, labral lesions, and impingement pits. Prevalence estimates of cam-type deformities and increased acetabular depths were estimated, and relationships between deformities and signs of joint damage were examined using logistic regression models.
  
  
  RESULTS
  The study included 283 subjects, and 80 asymptomatic females with a mean age of 19.3 years attended MRI. Fifteen showed some evidence of cam-type deformities, but none were scored to be definite. The overall prevalence was therefore 0% [95% confidence interval (95% CI) 0-5%]. The prevalence of increased acetabular depth was 10% (95% CI 5-19). No association was found between increased acetabular depth and decreased internal rotation of the hip. Increased acetabular depth was not associated with signs of labral damage.
  
  
  CONCLUSIONS
  Definite cam-type deformities in women are rare compared to men, whereas the prevalence of increased acetabular depth is higher, suggesting that femoroacetabular impingement has different gender-related biomechanical mechanisms.
authors: Hip Service, Schulthess Clinic, Zürich, Switzerland and University of Bern, Switzerland.
authors: M
authors: M
authors: Leunig
authors: P
authors: P
authors: Jüni
authors: S
authors: S
authors: Werlen
authors: A
authors: A
authors: Limacher
authors: E
authors: E
authors: Nüesch
authors: C W
authors: CW
authors: Pfirrmann
authors: S
authors: S
authors: Trelle
authors: A
authors: A
authors: Odermatt
authors: W
authors: W
authors: Hofstetter
authors: R
authors: R
authors: Ganz
authors: S
authors: S
authors: Reichenbach
mesh_terms: D000077:Acetabulum / Q000473:pathology; D000293:Adolescent; D003430:Cross-Sectional Studies; D005260:Female; D057925:Femoracetabular Impingement / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology / Q000503:physiopathology; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015995:Prevalence; D016059:Range of Motion, Articular; D012737:Sex Factors; D013557:Switzerland / Q000453:epidemiology; D055815:Young Adult