90 patients with knee cartilage defects were randomized to receive either particulated costal allocartilage with microfracture (n=44) or microfracture alone (n=46). The primary outcome of interest included Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scores. Secondary outcomes included International Knee Documentation Committee (IKDC) scores, pain on a Visual Analog Scale (VAS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and the incidence of adverse events. The particulated costal allocartilage group showed significantly better MOCART total scores. Similarly, the particulated costal allocartilage group showed significantly better VAS pain and KOOS pain scores at 24 weeks, with significantly better KOOS sports, symptoms, pain, and activities of daily living at 12 weeks. No differences were apparent in IKDC and all outcomes at 48 weeks.