In this review we explore the past, present and future treatment of osteoarthritis using autologous and allogeneic bone marrow mesenchymal stem cells (MSCs). Osteoarthritis is one of the most prevalent joint diseases worldwide. It causes pain, loss of function and may lead to disability. At a cellular level, osteoarthritis causes biochemical changes in the composition of cartilage leading to progressive tissue degeneration. The majority of conventional treatments involve symptom control but offer only modest clinical benefits without any reversal of the cellular degeneration. Cell-based therapies in animal models have shown encouraging results and there are now a number of human case reports, pilot studies and follow-up studies that demonstrate the reversal of lesion formation. Opus Biological has designed a therapy and follow-up algorithm utilizing the feasibility and safety studies conducted in recent years to offer patients MSCs as a valid alternative to other conventional therapies for treatment of chronic osteoarthritis. MSC therapy for osteoarthritis does not require hospitalization, is a minimally invasive and low risk procedure, provides pain relief and significantly improves cartilage quality thereby enhancing joint function.