The present invention relates to methods of treating ADAMTS-5-associated diseases and particularly osteoarthritis comprising administering an agent capable of modulating ADMATS-5 activity to a subject afflicted with the disease. The agent is preferably a biaryl sulfonamide compound. The invention is based, in part, on the discovery that transgenic animals that do not express functional ADAMTS-5 show a reduction in the degree of osteoarthritis after the induction of osteoarthritis as compared to WT animals. Furthermore, the ADAMTS-5 transgenic animals have reduced aggrecanase activity in articular tissue as compared to WT animals. These animals are good models for ADAMTS-5-associated diseases, and for screening of drugs useful in the treatment and/or prevention of these diseases. There are no other animal models in which the deletion of the activity of a single gene is capable of abrogating the course of osteoarthritis. Accordingly, these animals also show that osteoarthritis can be prevented and/or treated by administering to a subject an ADAMTS-5 inhibitory agent and particularly an agent capable of inhibiting the aggrecanase activity of ADAMTS-5.