Extracellular Matrix Cartilage Allograft and Particulate Cartilage Allograft for Osteochondral Lesions of the Knee and Ankle Joints: A Systematic Review

Background: Extracellular matrix cartilage allografts (EMCAs) and particulate cartilage allografts (PCAs) are relatively new biologics that may improve the quality of cartilage regeneration after bone marrow stimulation. The increasing popularity of these novel biologics in the treatment of osteochondral lesions (OCLs) of the knee and ankle joints prompts a systematic evaluation of their efficacies. Purpose: The purpose of this systematic review was to clarify the effectiveness of EMCAs and PCAs on cartilage regeneration. Study Design: Systematic review; Level of evidence, IV. Methods: Two reviewers searched MEDLINE and Embase in February 2016 based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Predetermined variables from each study were extracted and analyzed. Results: For EMCAs, 1 in vitro study and 2 clinical studies for OCLs of the ankle joint were found. For PCAs, 3 in vitro studies, 5 clinical studies for OCLs of the knee joint, and 5 clinical studies for OCLs of the ankle joint were found. For all studies, in vitro chondrogenesis and clinical outcomes favored EMCAs and PCAs. However, the highest level of evidence was IV, and the methodological quality of evidence was indicated to be poor. Conclusion: Both EMCAs and PCAs have yielded favorable outcomes in both in vitro and clinical studies. However, the available studies were of limited data with significant confounding factors. Therefore, it is unclear whether the effectiveness of these novel biologics is any greater than that of bone marrow stimulation alone in the repair of knee and ankle cartilage.