title: Early resumption of physical activities leads to inferior clinical outcomes after matrix-based autologous chondrocyte implantation in the knee.
abstract: OBJECTIVE
  Matrix-based autologous chondrocyte implantation is a well-established operation procedure for full cartilage defects. When to resume physical activity after matrix-based autologous chondrocyte implantation is controversial. Our hypothesis was that early resumption of physical activity leads to a worse clinical outcome after matrix-based autologous chondrocyte implantation in the knee two years post-operatively. Physical activity is defined as any kind of impact sport.
  
  
  METHODS
  Forty-four patients with cartilage defects of the knee were treated with matrix-based autologous chondrocyte implantation (Novocart3D). All patients were assessed preoperatively and after a period of 24 months with the University of California Los Angeles (UCLA) Activity score. The return to physical activities or sports after matrix-based autologous chondrocyte implantation was documented. Patients were evaluated using the International Knee Documentation Committee Knee Examination Form and visual analogue scale for pain after 6, 12 and 24 months.
  
  
  RESULTS
  Fifty-five percent showed an unchanged level of physical activity in the UCLA Activity score post-operatively. About 35% showed a lower level and 10% a higher level of physical activity. The average return to physical activities or sports after matrix-based autologous chondrocyte implantation procedure was 10.2 months. Patients with a later return of sports after 12 months showed significantly better clinical results after two years. In particular, patients who started practicing impact sport after 12 months post-operatively showed significantly better results.
  
  
  CONCLUSIONS
  Resuming physical activity including impact sports without waiting at least 12 months after the operation leads to inferior outcomes up to 24 months after matrix-based autologous chondrocyte implantation.
  
  
  METHODS
  Level IV.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistr. 15, 81377, Munich, Germany, thomas.niethammer@med.uni-muenchen.de.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Niethammer
authors.forename: Peter E
authors.initials: PE
authors.lastname: Müller
authors.forename: Elem
authors.initials: E
authors.lastname: Safi
authors.forename: Andreas
authors.initials: A
authors.lastname: Ficklscherer
authors.forename: Björn P
authors.initials: BP
authors.lastname: Roßbach
authors.forename: Volkmar
authors.initials: V
authors.lastname: Jansson
authors.forename: Matthias F
authors.initials: MF
authors.lastname: Pietschmann
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000534:rehabilitation* / Q000601:surgery; D002357:Cartilage Diseases / Q000534:rehabilitation* / Q000601:surgery; D002358:Cartilage, Articular / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000534:rehabilitation* / Q000601:surgery; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D019637:Orthopedic Procedures / Q000009:adverse effects; D011182:Postoperative Care; D020127:Recovery of Function; D014182:Transplantation, Autologous / Q000009:adverse effects; D055815:Young Adult