title: The relationship between the frequency of football practice during skeletal growth and the presence of a cam deformity in adult elite football players.
abstract: OBJECTIVE
  Cam deformity (CD) is likely a bony adaptation in response to high-impact sports practice during skeletal growth. We ascertained whether a dose-response relationship exists between the frequency of football practice during skeletal growth and the presence of a CD in adulthood, and if the age at which a football player starts playing football is associated with the presence of a CD in adulthood.
  
  
  METHODS
  Prevalence of a CD (α angle>60°) and a pathological CD (α angle>78°) was studied using standardised anteroposterior (AP) and frog-leg lateral (FLL) radiographs that were obtained during seasonal screening. The age of starting to play football with a low frequency (LF; ≤3 times/week) and high frequency (HF; ≥4 times/week) was retrospectively assessed. The differences in prevalence of a CD per hip, in either view, between groups were calculated by logistic regression with generalised estimating equations.
  
  
  RESULTS
  63 players (mean(±SD) age 23.1(±4.2) years) participated, yielding 126 hips for analysis. The prevalence of a CD in the FLL was 40% (n=82) in players who started playing HF football from the age of 12 years or above, and 64% (n=44) in those playing HF football before the age of 12 years (p=0.042). This was also true for a pathological CD (12% vs 30%, p=0.038). The AP views revealed no difference.
  
  
  CONCLUSIONS
  Our results indicate a probable dose-response relationship between the frequency of football practice during skeletal growth and the development of a CD, which should be confirmed in future prospective studies.
authors.affiliation: Sports Rehabilitation and Manual Therapy Department, Physiotherapy Utrecht Oost, Utrecht, The Netherlands Department of Orthopaedics and Sports Traumatology, Academic Medical Centre Amsterdam, Amsterdam, The Netherlands.
authors.forename: Igor
authors.initials: I
authors.lastname: Tak
authors.affiliation: Sports Medicine Department, Sports Groin Pain Centre, Aspetar Hospital, Doha, Qatar.
authors.forename: Adam
authors.initials: A
authors.lastname: Weir
authors.affiliation: Private Practice Physiotherapy Dukenburg, Nijmegen, The Netherlands.
authors.forename: Rob
authors.initials: R
authors.lastname: Langhout
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, Rotterdam, The Netherlands.
authors.forename: Jan Hendrik
authors.initials: JH
authors.lastname: Waarsing
authors.affiliation: Amsterdam University of Applied Sciences, School of Sports & Nutrition, Amsterdam, The Netherlands. Codarts University for the Arts, Rotterdam, The Netherlands.
authors.forename: Janine
authors.initials: J
authors.lastname: Stubbe
authors.affiliation: Department of Orthopaedics and Sports Traumatology, Academic Medical Centre Amsterdam, Amsterdam, The Netherlands.
authors.forename: Gino
authors.initials: G
authors.lastname: Kerkhoffs
authors.affiliation: Department of Orthopaedics, Erasmus University Medical Centre, Rotterdam, The Netherlands.
authors.forename: Rintje
authors.initials: R
authors.lastname: Agricola
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000254:growth & development*; D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000209:etiology; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D016916:Joint Deformities, Acquired / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D008297:Male; D009426:Netherlands; D011859:Radiography; D012189:Retrospective Studies; D012916:Soccer / Q000502:physiology*; D055815:Young Adult
keywords: Bone; Growth; Hip; Radiology; Risk factor