A systematic review including 130 studies with a total of 9 879 subjects was abstracted in DARE. 4 studies used a clinical trial design, 53 were prospective cohort studies, 77 historical studies, and 20 studies were of undetermined design. Across all studies, the typical patient experienced a 100% improvement in global knee-rating score, mean value 44.0, and 89.3% of patients were reported to have good or excellent outcomes (mean follow-up of 4.1 years). The overall rate of revision was 3.8 during a mean follow-up of 4.1 years.