title: Long-term outcomes after first-generation autologous chondrocyte implantation for cartilage defects of the knee.
abstract: BACKGROUND
  Autologous chondrocyte implantation (ACI) represents an established surgical therapy for large cartilage defects of the knee joint. Although various studies report satisfying midterm results, little is known about long-term outcomes.
  
  
  OBJECTIVE
  To evaluate long-term clinical and magnetic resonance imaging (MRI) outcomes after ACI.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Between January 1997 and June 2001, a total of 86 patients were treated with ACI for isolated cartilage defects of the knee. The mean patient age at the time of surgery was 33.3 ± 10.2 years, and the mean defect size was 6.5 ± 4.0 cm(2). Thirty-four defects were located on the medial femoral condyle and 13 on the lateral femoral condyle, while 6 patients were treated for cartilage defects of the trochlear groove and 17 for patellar lesions. At a mean follow-up of 10.9 ± 1.1 years, 70 patients (follow-up rate, 82%) treated for 82 full-thickness cartilage defects of the knee were available for an evaluation of knee function using standard instruments, while 59 of these patients were additionally evaluated by 1.5-T MRI to quantify the magnetic resonance observation of cartilage repair tissue (MOCART) score. Clinical function at follow-up was assessed by means of the Lysholm score, the International Knee Documentation Committee (IKDC) score, and the Knee injury and Osteoarthritis Outcome Score (KOOS). Patient activity was assessed by the Tegner score. In addition, pain on a visual analog scale (VAS) and patient satisfaction were evaluated separately.
  
  
  RESULTS
  At follow-up, 77% reported being "satisfied" or "very satisfied." The mean IKDC score at follow-up was 74.0 ± 17.3. The mean Lysholm score improved from 42.0 ± 22.5 before surgery to 71.0 ± 17.4 at follow-up (P < .01). The mean pain score on the VAS decreased from 7.2 ± 1.9 preoperatively to 2.1 ± 2.1 postoperatively. The mean MOCART score was 44.9 ± 23.6. Defect-associated bone marrow edema was found in 78% of the cases. Nevertheless, no correlation between the MOCART score and clinical outcome (IKDC score) could be found (Pearson coefficient, r = 0.173).
  
  
  CONCLUSIONS
  First-generation ACI leads to satisfying clinical results in terms of patient satisfaction, reduction of pain, and improvement in knee function. Nevertheless, full restoration of knee function cannot be achieved. Although MRI reveals lesions in the majority of the cases and the overall MOCART score seems moderate, this could not be correlated with long-term clinical outcomes.
authors.affiliation: Philipp Niemeyer, Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, Hugstetter Strasse 55, D-79095 Freiburg, Germany. philipp.niemeyer@uniklinik-freiburg.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Niemeyer
authors.forename: Stella
authors.initials: S
authors.lastname: Porichis
authors.forename: Matthias
authors.initials: M
authors.lastname: Steinwachs
authors.forename: Christoph
authors.initials: C
authors.lastname: Erggelet
authors.forename: Peter C
authors.initials: PC
authors.lastname: Kreuz
authors.forename: Hagen
authors.initials: H
authors.lastname: Schmal
authors.forename: Markus
authors.initials: M
authors.lastname: Uhl
authors.forename: Nadir
authors.initials: N
authors.lastname: Ghanem
authors.forename: Norbert P
authors.initials: NP
authors.lastname: Südkamp
authors.forename: Gian
authors.initials: G
authors.lastname: Salzmann
mesh_terms: D000328:Adult; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D019637:Orthopedic Procedures; D020370:Osteoarthritis, Knee / Q000601:surgery; D010147:Pain Measurement; D017060:Patient Satisfaction; D016059:Range of Motion, Articular; D014182:Transplantation, Autologous
keywords: autologous chondrocyte implantation; cartilage; knee joint; long-term outcomes