Since a clear definition of early osteoarthritis (EOA) has not been set up, some critical questions concern its diagnosis and treatment. The upcoming of newly available drugs and innovative therapeutic approaches, such as regenerative medicine, foster a better knowledge of the problem by medical community. We have carried out an updated systematic review on both PubMed and Embase databases, searching for all the studies and researches published in medical literature in the last 32 years, addressing the issue of EOA definition, diagnosis, and treatment, with a special focus on EOA at hip and knee. Our review found out 211 and 447 (published from 1973 to 2015) articles, when searching on PubMed and Embase database, respectively. Among the 132 papers that met our inclusion criteria, only 1 article explicitly addressed the issue of EOA definition, but it was only an expert opinion, while all the other researches were focused on diagnosis or management of EOA. EOA has been defined with regards to the younger age of osteoarthritis onset and radiological damage (grade I–II of the Kellgren and Lawrence classification). A more clear classification of EOA, based on characteristics and symptoms of affected patients, should be delivered by scientific community in order to better identify subjects who might benefit from new expensive drugs and innovative therapeutic approaches.