title: Prevalence of Cam-Type Morphology in Elite Ice Hockey Players.
abstract: BACKGROUND
  Femoroacetabular impingement (FAI) has been increasingly recognized as a cause of hip pain in athletes at all levels of competition, specifically ice hockey players.
  
  
  OBJECTIVE
  The purpose of this study was to define the prevalence of cam and pincer radiographic deformity in elite ice hockey players. The hypothesis was that elite hockey players will have a higher prevalence of radiographic hip abnormalities compared with the general population.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  Anteroposterior and frog-leg lateral radiographs on 137 elite ice hockey players were prospectively obtained during the 2014-2015 preseason entrance examinations. Study participants included National Hockey League roster players as well as the respective farm team members. Demographic data were collected, including age, position, shooting side, and any history of hip pain or hip surgery. Patients with a history of hip surgery were excluded from the analysis. A single sports medicine fellowship-trained orthopaedic surgeon used standard radiographic measurements to assess for the radiographic presence of cam or pincer deformity. Radiographs with an alpha angle ≥55° on a frog-leg lateral view were defined as cam-positive. Each participant underwent a preseason physical examination with an assessment of hip range of motion and impingement testing.
  
  
  RESULTS
  A total of 130 elite ice hockey players were included in the analysis; 180 (69.4%) hips met radiographic criteria for cam-type deformity. The prevalence in right and left hips was 89 (69.5%) and 91 (70.0%), respectively; 70 (60.8%) players demonstrated bilateral involvement. Hips with cam deformity had a mean alpha angle of 67.7° ± 8.3° on the right and 68.9° ± 9.0° on the left. Of the patients with alpha angles ≥55°, 5.6% (5/89) had a positive anterior impingement test of the right hip, while 11% (10/91) had positive anterior impingement test of the left. Players with radiologic cam deformity had a statistically significant deficit in external rotation of the right hip, as well as in both internal and external rotation of the left hip, compared with those with normal alpha angles. When assessing for crossover sign, 64 of 107 (59.8%) had a positive radiographic finding. Forty-one players (38.3%) had evidence of a crossover sign of the right hip and 42 (39.3%) of the left. When comparing position players, goalies had the highest prevalence of cam-type deformity (93.8%) and the least acetabular coverage.
  
  
  CONCLUSIONS
  The study data suggest that elite ice hockey players have a significantly higher prevalence of radiographic cam deformity in comparison to what has been reported for the general population.
authors.affiliation: Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California, USA.
authors.forename: Frantz
authors.initials: F
authors.lastname: Lerebours
authors.affiliation: Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA Dallas Stars, National Hockey League, Dallas, Texas, USA.
authors.forename: William
authors.initials: W
authors.lastname: Robertson
authors.affiliation: ProHealth Care Associates, Lake Success, New York, USA New York Islanders, National Hockey League, New York, New York, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Neri
authors.affiliation: Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California, USA Anaheim Ducks, National Hockey League, Anaheim, California, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Schulz
authors.affiliation: Department of Orthopaedic Surgery, New York University Langone Medical Center, New York, New York, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Youm
authors.affiliation: Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California, USA Anaheim Ducks, National Hockey League, Anaheim, California, USA limpisvasti@hotmail.com.
authors.forename: Orr
authors.initials: O
authors.lastname: Limpisvasti
mesh_terms: D000328:Adult; D056352:Athletes; D003430:Cross-Sectional Studies; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging*; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006688:Hockey; D006801:Humans; D008297:Male; D015995:Prevalence; D055815:Young Adult
keywords: FAI; elite athletes; femoroacetabular impingement; ice hockey