title: Analysis of the autologous chondrocyte quality of matrix-based autologous chondrocyte implantation in the knee joint.
abstract: OBJECTIVE
  Matrix based autologous chondrocyte implantation is an established method for treatment of full cartilage defects in the knee joint, but little is known about the influence of the implanted autologous chondrocyte quality and its clinical value. The aim of this study is to evaluate the influence of the gene expression of the implanted autologous chondrocytes on the clinical outcomes in the follow-up period of three years.
  
  
  METHODS
  Biological parameters of the implanted chondrocytes were analysed histologically and immunohistologically. An analysis of the gene expression of the relevant chondrogenic dedifferentiation markers was performed as well. In order to detect the rate of apoptosis, we analysed specific apoptosis markers. To evaluate the clinical outcome, the International Knee Documentation Committee (IKDC) subjective score and the visual analogue scale (VAS) were used pre-operatively and after 0.5, one, two and three years.
  
  
  RESULTS
  Significantly improved clinical scores were observed. The subjective IKDC score increased from 50.6 ± 20.7 points to 69.3 ± 26.1 points at three years (p = 0.001). The implanted chondrocytes showed a typical expression of the chondrogenic markers with a high rate of collagen type II expression without dedifferentiation. The analysed differentiation, dedifferentiation and apoptosis markers showed no influence on the clinical outcome.
  
  
  CONCLUSIONS
  The implanted autologous chondrocytes have a high chondrogenic quality with a high rate of collagen type II expression without dedifferentiation. An influence of differentiation, de-differentiation and apoptosis marker gene expression on the clinical outcomes could not be found in a follow-up period of three years.
  
  
  METHODS
  Case series; Level of evidence, 3.
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany. thomas.niethammer@med.uni-muenchen.de.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Niethammer
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Limbrunner
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany.
authors.forename: Oliver B
authors.initials: OB
authors.lastname: Betz
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany.
authors.forename: Mehmet F
authors.initials: MF
authors.lastname: Gülecyüz
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany.
authors.forename: Matthias F
authors.initials: MF
authors.lastname: Pietschmann
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Feist
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Müller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017209:Apoptosis; D002357:Cartilage Diseases / Q000601:surgery*; D002358:Cartilage, Articular / Q000601:surgery*; D002454:Cell Differentiation; D002648:Child; D019902:Chondrocytes / Q000378:metabolism / Q000637:transplantation*; D024043:Collagen Type II / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011446:Prospective Studies; D014182:Transplantation, Autologous / Q000379:methods*; D055815:Young Adult
chemical_list: D024043:Collagen Type II
keywords: ACI; Autologous chondrocyte implantation; Cartilage; Chondrocyte