title: Incomplete defect filling after third generation autologous chondrocyte implantation.
abstract: BACKGROUND
  Third generation autologous chondrocyte implantation (ACI) is a suitable method for the treatment of cartilage defects in the knee joint. However, knowledge about the development of graft thickness and the clinical relevance of incomplete defect filling in the postoperative course is low. This prospective study analyses the graft integration into the surrounding cartilage, with special consideration of the graft thickness.
  
  
  METHODS
  A total of 71 consecutive patients with 79 cartilage defects were treated with third generation autologous chondrocyte implantation (NOVOCART 3D) in the knee. Follow-up magnetic resonance imaging (MRI) was performed at 0.25, 0.5, 1 and 2 years. Graft thickness was measured compared to the surrounding healthy cartilage. The International Knee Documentation Committee (IKDC) scoring system and the visual analogue scale (VAS) were used for clinical evaluation. Cartilage defect filling was classified as the percentage of the surrounding cartilage.
  
  
  RESULTS
  The average graft thickness showed a significant increase between 3 and 6 months after autologous chondrocyte implantation. Incomplete defect filling occurred in 44 (55.7%) cases. Of these, 33 cases showed incomplete defect filling grade I (> 75%), 10 cases were grade II (> 50%) and one case grade III (> 25%). Incomplete defect filling grade IV (< 25%) was not observed. Incomplete defect filling occurred significantly more often in women (p = 0.021), without worse clinical results.
  
  
  CONCLUSIONS
  Graft thickness after third generation autologous chondrocyte implantation shows increasing graft thickness over the period of 2 years postoperatively. A high rate of incomplete defect filling in the surrounding cartilage was observed, without worse clinical results.
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Munich, Germany.
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: 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: Andreas
authors.initials: A
authors.lastname: Ficklscherer
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: Florian
authors.initials: F
authors.lastname: Hammerschmid
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
keywords: autologous chondrocyte implantation; cartilage defect; incomplete defect filling