Treatment of Articular Cartilage Lesions of the Knee by Microfracture or Autologous Chondrocyte Implantation: A Systematic Review

PURPOSE: We performed a systematic review of the treatment of articular cartilage lesions of the knee by microfracture or autologous chondrocyte implantation to determine the differences in patient outcomes after these procedures. METHODS: We searched PubMed/Medline, Embase, and The Cochrane Library databases in the period from January 10 through January 20, 2013, and included 34 articles in our qualitative analysis. RESULTS: All studies showed improvement in outcome scores in comparison with baseline values, regardless of the treatment modality. The heterogeneity of the results presented in the studies precluded a meta-analysis. CONCLUSIONS: Microfracture appears to be effective in smaller lesions and is usually associated with a greater proportion of fibrocartilage production, which may have an effect on durability and eventual failure. Autologous chondrocyte implantation is an effective treatment that may result in a greater proportion of hyaline-like tissue at the repair site, which may in turn have a beneficial effect on durability and failure; it appears to be effective in larger lesions. Autologous chondrocyte implantation with periosteum has been shown to be associated with symptomatic cartilage hypertrophy more frequently than autologous chondrocyte implantation with collagen membrane. Matrix-associated autologous chondrocyte implantation is technically less challenging than the other techniques available, and in lesions greater than 4 cm(2), it has been shown to be more effective than microfracture. LEVEL OF EVIDENCE: Level IV, systematic review of Level I-IV studies.