title: Autologous chondrocyte implantation in children and adolescents.
abstract: OBJECTIVE
  Autologous chondrocyte implantation (ACI) is a well-established treatment method for cartilage defects in knees. Age-related grouping was based on expression data of cartilage-specific markers. Specificities of ACI in the different populations were analysed.
  
  
  METHODS
  Two hundred and sixty-seven patients undergoing ACI in the knee between 2006 and 2010 were included in this analysis. Cell characteristics and expression data of cartilage-specific surface markers as CD44, aggrecan and collagen type II were statistically analysed for age association. Epidemiological data of the defined groups were compared. Course of treatment was evaluated using MRI.
  
  
  RESULTS
  A correlation analysis showed statistically significant associations between age and aggrecan or collagen type II expression in all patients <30 years. A cluster analysis could predict age-dependent expression of these markers separating groups with an average age of 18.1 ± 2.3 and 23.6 ± 4.2 years, respectively (p < 0.02). Discriminance analysis suggested the age border between adults and juveniles at about 20 years. There was no influence of age on cell characteristics or CD44 expression. In the 19 of 267 patients with an age ≤18 years, gender distribution was not different compared to adults, but patella was significantly more affected. Cartilage lesions were mainly caused by osteochondritis dissecans (OCD) and trauma. The Knee Osteoarthritis Scoring System in MRI reached 4.8 ± 2.3 points before, declining to 3.3 ± 2.3 points 6 and 12 months after the operation.
  
  
  CONCLUSIONS
  Age-related expression of cartilage-specific markers allows definition of adolescents in cartilage regenerating surgery. Chondromalacia in these patients is mainly caused by OCD or trauma.
  
  
  METHODS
  Case series, Level IV.
authors.affiliation: Department of Orthopaedic Surgery, University of Freiburg Medical Centre, Hugstetter Str. 55, 79106, Freiburg im Breisgau, Germany. hagen.schmal@freenet.de
authors.forename: H
authors.initials: H
authors.lastname: Schmal
authors.forename: J M
authors.initials: JM
authors.lastname: Pestka
authors.forename: G
authors.initials: G
authors.lastname: Salzmann
authors.forename: P C
authors.initials: PC
authors.lastname: Strohm
authors.forename: N P
authors.initials: NP
authors.lastname: Südkamp
authors.forename: P
authors.initials: P
authors.lastname: Niemeyer
mesh_terms: D000293:Adolescent; D000328:Adult; D053674:Aggrecans / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002357:Cartilage Diseases / Q000378:metabolism / Q000628:therapy*; D002648:Child; D019902:Chondrocytes / Q000378:metabolism / Q000637:transplantation*; D024043:Collagen Type II / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014182:Transplantation, Autologous; D055815:Young Adult
chemical_list: D053674:Aggrecans; D015415:Biomarkers; D024043:Collagen Type II