title: The development of Cam-type deformity in adolescent and young male soccer players.
abstract: BACKGROUND
  Cam impingement is a well-recognized cause of hip pain and might cause osteoarthritis of the hip. Clinically, cam impingement is mostly observed in young, active male patients, but only a few studies have focused on the manifestation of cam-type deformities during skeletal development.
  
  
  OBJECTIVE
  To determine the age of onset and prevalence of cam-type deformities in young male soccer players versus controls.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  In this study, 89 elite preprofessional soccer players and 92 controls aged 12 to 19 years were included. In the soccer players, range of motion and impingement tests were performed. Both an anteroposterior (AP) pelvic radiograph and a frog-leg lateral radiograph of the hip were obtained according to a standardized protocol. Controls with both an AP pelvic and a frog-leg lateral radiograph and no hip disorders were obtained from radiology databases. The α angle was automatically determined in all radiographs, using a threshold value of 60° to define a cam-type deformity. Further, all radiographs were scored using a 3-point scoring system. The anterosuperior head-neck junction was classified as (1) normal, (2) flattened, or (3) having a prominence. Differences in prevalence were tested using logistic regression. Differences in range of motion were calculated using generalized estimating equations.
  
  
  RESULTS
  An α angle >60° was already found at the age of 12 years in some soccer players and controls. A cam-type deformity defined by α angle tended to be more prevalent in soccer players (26%) than in controls (17%; P = .31). In 13% of soccer players, a prominence was visible on radiographs and was first seen at the age of 13 years. The anterosuperior flattening (56% vs 18%, P = .0001) and prominence (13% vs 0%, P < .03) were more prevalent in soccer players than in controls.
  
  
  CONCLUSIONS
  Cam-type deformities were recognizable and present from the age of 13 years and were more prevalent in soccer players than in their nonathletic peers. Cam-type deformity develops during adolescence and is likely to be influenced by high-impact sports practice.
authors.affiliation: Department of Orthopaedics, Erasmus MC University Medical Center, Rotterdam, the Netherlands. r.agricola@erasmusmc.nl
authors.forename: Rintje
authors.initials: R
authors.lastname: Agricola
authors.forename: Johannes H J M
authors.initials: JH
authors.lastname: Bessems
authors.forename: Abida Z
authors.initials: AZ
authors.lastname: Ginai
authors.forename: Marinus P
authors.initials: MP
authors.lastname: Heijboer
authors.forename: Rianne A
authors.initials: RA
authors.lastname: van der Heijden
authors.forename: Jan A N
authors.initials: JA
authors.lastname: Verhaar
authors.forename: Harrie
authors.initials: H
authors.lastname: Weinans
authors.forename: Jan H
authors.initials: JH
authors.lastname: Waarsing
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D002648:Child; D002657:Child Development; D003430:Cross-Sectional Studies; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D011859:Radiography; D016059:Range of Motion, Articular; D012916:Soccer / Q000502:physiology; D055815:Young Adult