title: Autologous chondrocyte implantation of the knee: multicenter experience and minimum 3-year follow-up.
abstract: OBJECTIVE
  To determine clinical outcome and graft survivorship in patients undergoing autologous chondrocyte implantation (ACI) for the repair of chondral defects of the knee.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  19 centers in the United States.
  
  
  METHODS
  50 patients (37 males, 13 females). Mean age was 36 years (range: 19-53). Defects were grade III or IV with a mean size of 4.2 cm 2. All patients had a minimum of 36 months postoperative follow-up.
  
  
  METHODS
  Clinician and patient evaluation based on the modified Cincinnati Knee Rating System. Graft failure was defined as replacement or removal of the graft due to mechanical symptoms or pain.
  
  
  RESULTS
  Clinician and patient evaluation indicated median improvements of 4 and 5 points, respectively, at 36 months following ACI (p < 0.001). Previous treatment with marrow stimulation techniques and size of defect did not impact the results with ACI. The most common adverse events reported were adhesions and arthrofibrosis and hypertrophic changes. Three patients had graft failure and required reimplantation or treatment with alternative cartilage repair techniques. Kaplan-Meier estimated freedom from graft failure was 94% at 36 months postoperatively (95% CI = 88-100%).
  
  
  CONCLUSIONS
  These results of this study indicate excellent graft survivorship using ACI as well as substantial improvement in functional outcome.
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, Children's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Micheli
authors.forename: J E
authors.initials: JE
authors.lastname: Browne
authors.forename: C
authors.initials: C
authors.lastname: Erggelet
authors.forename: F
authors.initials: F
authors.lastname: Fu
authors.forename: B
authors.initials: B
authors.lastname: Mandelbaum
authors.forename: J B
authors.initials: JB
authors.lastname: Moseley
authors.forename: D
authors.initials: D
authors.lastname: Zurakowski
mesh_terms: D000328:Adult; D002357:Cartilage Diseases / Q000145:classification / Q000601:surgery*; D002358:Cartilage, Articular / Q000293:injuries* / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007717:Knee / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011446:Prospective Studies; D016059:Range of Motion, Articular; D012086:Reoperation; D014182:Transplantation, Autologous / Q000379:methods; D017211:Treatment Failure; D016896:Treatment Outcome; D014481:United States; D014942:Workers' Compensation