title: Prevalence and incidence of new meniscus and cartilage injuries after a nonoperative treatment algorithm for ACL tears in skeletally immature children: a prospective MRI study.
abstract: BACKGROUND
  The increased risk of long-term osteoarthritis from concomitant injuries to the menisci or cartilage after an anterior cruciate ligament (ACL) injury in adults is well established. In skeletally immature children, ACL reconstruction is often recommended to reduce the risk of new intra-articular injuries. However, the prevalence and incidence of new injuries after nonoperative treatment of ACL injuries in children are unknown.
  
  
  OBJECTIVE
  To prospectively investigate the incidence of new injuries to the menisci and joint cartilage in nonoperatively treated, skeletally immature children with a known ACL injury by use of bilateral 3.0-T MRI.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Forty skeletally immature children with a ruptured ACL (41 knees) followed a nonoperative treatment algorithm and were evaluated with bilateral 3.0-T MRI on 2 occasions (MRI1 and MRI2). The intra-articular structures were analyzed by 2 independent MRI radiologists. Monitoring of participation in physical activities was accomplished through a monthly online activity survey. Descriptive statistics and frequencies were extracted from the scoring forms and compared using the Fisher exact test.
  
  
  RESULTS
  Fourteen girls (35%) and 26 boys (65%) with a mean age of 11.0 ± 1.4 years at the time of injury were included. Time from injury to the final follow-up was 3.8 ± 1.4 years. Eighty-eight percent of the ACL-deficient children confirmed monthly participation in pivoting sports and/or in physical education classes in school. The prevalence of meniscus injuries in the 28 nonreconstructed knees was 28.5% at MRI1 and MRI2, and the incidence of new meniscus and cartilage injuries in the nonreconstructed knees from MRI1 to MRI2 was 3.6%. Thirteen children underwent ACL reconstruction, with a prevalence of meniscus procedures of 46.2%. The incidence of new meniscus injuries from diagnostic MRI to final follow-up was 19.5%. Surgical treatments for meniscus injuries were performed in 8 of the 41 knees.
  
  
  CONCLUSIONS
  The incidence of new injuries to menisci and joint cartilage was low between MRI1 and MRI2 in the 28 nonreconstructed knees. Thirty-two percent of the knees required ACL reconstruction, and 19.5% required meniscus surgeries during the 3.8 ± 1.4 years of follow-up from injury. Further follow-up is needed to evaluate the long-term knee health in these children.
authors.affiliation: Norwegian Research Center for Active Rehabilitation (NAR), Norwegian School of Sport Sciences, Department of Sport Medicine, PO Box 4014 Ullevål Stadion, 0806 Oslo, Norway. havard.moksnes@nih.no
authors.forename: Håvard
authors.initials: H
authors.lastname: Moksnes
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.forename: May Arna
authors.initials: MA
authors.lastname: Risberg
mesh_terms: D000293:Adolescent; D000465:Algorithms; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D001915:Braces; D002358:Cartilage, Articular / Q000293:injuries*; D002648:Child; D003661:Decision Support Techniques; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery; D019637:Orthopedic Procedures; D015995:Prevalence; D011446:Prospective Studies; D000070600:Tibial Meniscus Injuries; D016896:Treatment Outcome
keywords: anterior cruciate ligament; cartilage; magnetic resonance imaging; meniscus; skeletally immature