The purpose of this study was to conduct a systematic review and meta-analysis analyzing the impacts of mesenchymal stem cells on cartilage regeneration and patient-reported pain and function. This study was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines applying a PRISMA checklist. Researchers carried out to search the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (2008-2019), EMBASE (2008-2019), and MEDLINE (2008-2019) in July 2019 for literature reporting use of stem cells to treat knee osteoarthritis or chondral defects. Researchers included 25 studies including a total of 439 individuals. It was shown that the pooled standard mean difference from meta-analyses exhibited statistically significant impacts of MSC on self-reported physical function but not self-reported pain. MSCs served functional advantage only in patients who had undergone concomitant surgery. Nevertheless, this must be interpreted with caution as there was substantial variability in MSC composition and mode of delivery. A significant improvement in cartilage volume was provided by MSC treatment, but not cartilage quality. Primary findings regarding therapeutic properties of MSC treatment imply significant heterogeneity in the current literature and risk of bias is not negligible.