title: Clinical examination and ultrasound of self-reported snapping hip syndrome in elite ballet dancers.
abstract: BACKGROUND
  Although snapping hip syndrome is commonly reported in ballet dancers, the prevalence, impact, and underlying mechanism of this condition have not been formally studied within a cohort of dancers.
  
  
  OBJECTIVE
  To determine the prevalence, associated factors, and mechanisms of snapping hip and to investigate self-reported snapping with physical and ultrasound examination.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  A snapping hip questionnaire was completed by 87 unselected elite ballet dancers at 2 institutions. Twenty-six of the dancers (50 hips) who were able to voluntarily snap their hips were selected from this group for further physical examination by 2 clinicians to determine whether there was a palpable snap, and each underwent an ultrasound examination of his or her hips.
  
  
  RESULTS
  Ninety-one percent of dancers reported snapping hip, of which most (80%) had bilateral symptoms. Fifty-eight percent had pain associated with the snap, and 7% had taken time off dance because of this condition. Sixty percent of the dancers could voluntarily snap their hip. One or more of 3 dance movements elicited the snapping in 81%. The clinicians could palpate 46 of the 50 self-reported snapping hips. Ultrasound showed a snapping iliopsoas tendon in 59% of the hips and the iliotibial band snapping in 4%. In one third of cases, ultrasound was not helpful in identifying the cause of the snapping.
  
  
  CONCLUSIONS
  Snapping hip is extremely common in ballet dancers. Some dancers have significant pain, yet many are asymptomatic. Self-reported snapping is likely to be palpable by the clinician. Iliotibial band snapping is evident by physical examination and ultrasound. Iliopsoas snapping was most common and required ultrasonic confirmation.
authors.affiliation: Toronto Rehabilitation Institute, University of Toronto, Toronto, Ontario M5G2A2, Canada. paul.winston@utoronto.ca
authors.forename: Paul
authors.initials: P
authors.lastname: Winston
authors.forename: Raza
authors.initials: R
authors.lastname: Awan
authors.forename: J David
authors.initials: JD
authors.lastname: Cassidy
authors.forename: Robert K
authors.initials: RK
authors.lastname: Bleakney
mesh_terms: D000293:Adolescent; D000328:Adult; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003615:Dancing / Q000293:injuries*; D005260:Female; D025981:Hip Injuries / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D008297:Male; D010808:Physical Examination; D015995:Prevalence; D016059:Range of Motion, Articular; D011795:Surveys and Questionnaires; D013577:Syndrome; D013708:Tendon Injuries / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D014463:Ultrasonography