title: [Factors that influence clinical outcome following autologous chondrocyte implantation for cartilage defects of the knee].
abstract: OBJECTIVE
  Since its introduction in 1994, autologous chondrocyte implantation (ACI) has become an established surgical treatment for symptomatic isolated cartilage defects of the knee. Success rates vary between 80 and 95% and the clinical outcome seems to depend on various individual factors. The aim of the present review article is to summarise factors that affect clinical outcome following ACI for treatment of symptomatic cartilage defects of the knee based upon the scientific literature available on this topic.
  
  
  METHODS
  The present publication represents a non-systematic review including publications which were considered relevant describing factors that influence clinical outcome following ACI for treatment of symptomatic full thickness cartilage defects of the knee. In order to identify relevant literature concerning complications following cartilage repair, medical databases including "medline", "ovid" and "web of science" were searched for the terms "autologous chondrocyte implantation", "autologous chondrocyte transplantation", "prognostic factor", "clinical outcome", "cartilage repair", "cartilage defect" and "cartilage regeneration". The literature search was performed in April 2010.
  
  
  RESULTS
  Factors that influence clinical outcome following ACI for treatment of cartilage defects of the knee include patient-specific parameters on the one hand, such as body mass index, nicotine abusus, patients age, prior surgical treatment, duration of symptoms and more, and defect characteristics such as containment, defect location, defect size, number of defects treated, on the other hand. Furthermore, surgical technique, cell quality and rehabilitation seem to significantly influence the clinical outcome following autologous chondrocyte implantation. Among all factors identified as relevant for clinical outcome, some of these parameters are fixed and cannot be changed by either the surgeon nor the patient, while others can be influenced and even changed during the treatment and rehabilitation of a patient who underwent ACI.
  
  
  CONCLUSIONS
  Knowledge of all relevant parameters that influence clinical outcome following ACI is essential in order to achieve an optimal clinical outcome in patients with cartilage defects of the knee. This paper presents a review of the scientific literature available which focuses on the questions as to what parameters influence the outcome of a patient following ACI for treatment of cartilage defects of the knee. No isolated factors could be identified that influence the outcome following ACI alone, but it seems that clinical outcome is influenced by many different parameters. These parameters should be considered carefully, at the time of decision about what kind of treatment is applied. Furthermore, the patient should be informed especially about those parameters which can be influenced by him-/herself in order to create good prerequisites for the surgical treatment.
authors.affiliation: Department für Orthopädie und Traumatologie, Universitätsklinikum Freiburg, Hugstetterstrasse 55, Freiburg. philipp.niemeyer@uniklinik-freiburg.de
authors.forename: P
authors.initials: P
authors.lastname: Niemeyer
authors.forename: G M
authors.initials: GM
authors.lastname: Salzmann
authors.forename: A
authors.initials: A
authors.lastname: Hirschmüller
authors.forename: N P
authors.initials: NP
authors.lastname: Südkamp
mesh_terms: D002357:Cartilage Diseases / Q000453:epidemiology* / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D006801:Humans; D020370:Osteoarthritis, Knee / Q000453:epidemiology* / Q000601:surgery*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome