Chondrogen is a preparation of adult mesenchymal stem cells (MSCs) in a solution containing hyaluronic acid. Preclinical studies have shown that injection of Chondrogen aids in the repair of meniscal tissue following meniscectomy. In Chondrogen treated subjects, surgically removed meniscal tissue was regenerated, cartilage surface was protected, and joint damage was decreased in comparison to control subjects. These benefits persisted at least one year.