title: Prevalence of chondral defects in athletes' knees: a systematic review.
abstract: OBJECTIVE
  To determine the prevalence of full-thickness focal chondral defects in the athlete's knee.
  
  
  METHODS
  We conducted a systematic review of multiple databases, evaluating studies of the prevalence of articular cartilage defects in athletes. Because of the heterogeneity of data, a meta-analysis could not be performed.
  
  
  RESULTS
  Eleven studies were identified for inclusion (931 subjects). All studies were level 4 evidence. Defects were diagnosed via magnetic resonance imaging, arthroscopy, or both. Forty percent of athletes were professionals (NBA and NFL). The overall prevalence of full-thickness focal chondral defects in athletes was 36% (range = 2.4%-75% between all studies). Fourteen percent of athletes were asymptomatic at the time of diagnosis. Patellofemoral defects (37%) were more common than femoral condyle (35%) and tibial plateau defects (25%). Medial condyle defects were more common than lateral (68% vs 32%), and patella defects were more common than trochlea (64% vs 36%). Meniscal tear (47%) was the most common concomitant knee pathological finding, followed by anterior cruciate ligament tear (30%) and then medial collateral ligament or lateral collateral ligament tear (14%).
  
  
  CONCLUSIONS
  Full-thickness focal chondral defects in the knee are more common in athletes than among the general population. More than one-half of asymptomatic athletes have a full-thickness defect. Further study is needed to define more precisely the prevalence of these lesions in this population.
authors.affiliation: Department of Orthopaedics, Division of Sports Medicine Cartilage Repair Center, The Ohio State University Medical Center, Columbus, OH 43221-3502, USA. david.flanigan@osumc.edu
authors.forename: David C
authors.initials: DC
authors.lastname: Flanigan
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Harris
authors.forename: Thai Q
authors.initials: TQ
authors.lastname: Trinh
authors.forename: Robert A
authors.initials: RA
authors.lastname: Siston
authors.forename: Robert H
authors.initials: RH
authors.lastname: Brophy
mesh_terms: D001182:Arthroscopy; D001265:Athletic Injuries / Q000175:diagnosis / Q000453:epidemiology*; D002358:Cartilage, Articular / Q000293:injuries*; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis / Q000453:epidemiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D015995:Prevalence