title: The comparison between the different generations of autologous chondrocyte implantation with other treatment modalities: a systematic review of clinical trials.
abstract: OBJECTIVE
  This paper aims to review the current evidence for autologous chondrocyte implantation (ACI) generations relative to other treatment modalities, different cell delivery methods and different cell source application.
  
  
  METHODS
  Literature search was performed to identify all level I and II studies reporting the clinical and structural outcome of any ACI generation in human knees using the following medical electronic databases: PubMed, EMBASE, Cochrane Library, CINAHL, SPORTDiscus and NICE healthcare database. The level of evidence, sample size calculation and risk of bias were determined for all included studies to enable quality assessment.
  
  
  RESULTS
  Twenty studies were included in the analysis, reporting on a total of 1094 patients. Of the 20 studies, 13 compared ACI with other treatment modalities, seven compared different ACI cell delivery methods, and one compared different cell source for implantation. Studies included were heterogeneous in baseline design, preventing meta-analysis. Data showed a trend towards similar outcomes when comparing ACI generations with other repair techniques and when comparing different cell delivery methods and cell source selection. Majority of the studies (80 %) were level II evidence, and overall the quality of studies can be rated as average to low, with the absence of power analysis in 65 % studies.
  
  
  CONCLUSIONS
  At present, there are insufficient data to conclude any superiority of ACI techniques. Considering its two-stage operation and cost, it may be appropriate to reserve ACI for patients with larger defects or those who have had inadequate response to other repair procedures until hard evidence enables specific clinical recommendations be made.
  
  
  METHODS
  II.
authors.affiliation: Clinical Investigation Centre, University Malaya Medical Centre, 59100, Kuala Lumpur, Malaysia. elyzarina07@yahoo.com.
authors.forename: Ely Zarina
authors.initials: EZ
authors.lastname: Samsudin
authors.affiliation: Clinical Investigation Centre, University Malaya Medical Centre, 59100, Kuala Lumpur, Malaysia.
authors.forename: Tunku
authors.initials: T
authors.lastname: Kamarul
mesh_terms: D002357:Cartilage Diseases / Q000628:therapy*; D002358:Cartilage, Articular / Q000293:injuries*; D019902:Chondrocytes / Q000637:transplantation*; D002986:Clinical Trials as Topic; D003365:Costs and Cost Analysis; D006801:Humans; D007718:Knee Injuries / Q000628:therapy*; D019637:Orthopedic Procedures / Q000191:economics / Q000379:methods; D014182:Transplantation, Autologous / Q000191:economics / Q000379:methods
keywords: Articular cartilage; Autologous chondrocyte implantation; Cartilage repair; Knee