title: What is the effect of matrices on cartilage repair? A systematic review.
abstract: BACKGROUND
  Articular cartilage has minimal endogenous ability to undergo repair. Multiple chondral restoration strategies have been attempted with varied results.
  
  
  OBJECTIVE
  The purpose of our review was to determine: (1) Does articular chondrocyte transplantation or matrix-assisted articular chondrocyte transplantation provide better patient-reported outcomes scores, MRI morphologic measurements, or histologic quality of repair tissue compared with microfracture in prospective comparative studies of articular cartilage repair; and (2) which available matrices for matrix-assisted articular chondrocyte transplantation show the best patient-reported outcomes scores, MRI morphologic measurements, or histologic quality of repair tissue?
  
  
  METHODS
  We conducted a systematic review of PubMed, CINAHL, and MEDLINE from March 2004 to February 2014 using keywords determined to be important for articular cartilage repair, including "cartilage", "chondral", "cell source", "chondrocyte", "matrix", "augment", "articular", "joint", "repair", "treatment", "regeneration", and "restoration" to find articles related to cell-based articular cartilage repair of the knee. The articles were reviewed by two authors (JDW, MKH), our study exclusion criteria were applied, and articles were determined to be relevant (or not) to the research questions. The Methodological Index for Nonrandomized Studies (MINORS) scale was used to judge the quality of nonrandomized manuscripts used in this review and the Jadad score was used to judge the quality of randomized trials. Seventeen articles were reviewed for the first research question and 83 articles were reviewed in the second research question from 301 articles identified in the original systematic search. The average MINORS score was 9.9 (62%) for noncomparative studies and 16.1 (67%) for comparative studies. The average Jadad score was 2.3 for the randomized studies.
  
  
  RESULTS
  Articular chondrocyte transplantation shows better patient-reported outcomes at 5 years in patients without chronic symptoms preoperatively compared with microfracture (p = 0.026). Matrix-assisted articular chondrocyte transplantation consistently showed improved patient-reported functional outcomes compared with microfracture (p values ranging from < 0.001 to 0.029). Hyalograft C(®) (Anika Therapeutics Inc, Bedford, MA, USA) and Chondro-gide(®) (Genzyme Biosurgery, Kastrup, Denmark) are the matrices with the most published evidence in the literature, but no studies comparing different matrices met our inclusion criteria, because the literature consists only of uncontrolled case series.
  
  
  CONCLUSIONS
  Matrix-assisted articular chondrocyte transplantation leads to better patient-reported outcomes in cartilage repair compared with microfracture; however, future prospective research is needed comparing different matrices to determine which products optimize cartilage repair.
  
  
  METHODS
  Level IV, therapeutic study.
authors.affiliation: Department of Orthopaedic Surgery, University of Utah, 590 Wakara Way, Salt Lake City, UT, 84108, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Wylie
authors.forename: Melissa K
authors.initials: MK
authors.lastname: Hartley
authors.forename: Ashley L
authors.initials: AL
authors.lastname: Kapron
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Aoki
authors.forename: Travis G
authors.initials: TG
authors.lastname: Maak
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology / Q000637:transplantation*; D050723:Fractures, Bone / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000379:methods*; D013997:Time Factors; D054457:Tissue Scaffolds; D016896:Treatment Outcome; D014945:Wound Healing