Intra-articular injections in the management of canine osteoarthritis : a review of the literature

The amount of information available on the use of intra-articular medications in the management of canine osteoarthritis is scarce. The purpose of the review was to investigate whether the scientific evidence on the use of intra-articular medications in veterinary and human medicine is strong enough to justify their use in the management of canine osteoarthritis. Corticosteroids and hyaluronic acid are the most commonly used intra-articular medications both in human and veterinary medicine. Corticosteroids are used because of their ability to suppress inflammation effectively. Long-acting corticosteroid preparations, such as methylprednisolone acetate and triamcinolone acetonide, are preferred for intra-articular use. In Finland methylprednisolone acetate is registered for dogs at a dose of 20 mg given in a large joint cavity. The approved dose of triamcinolone acetonide in the United States is 1,0-3,0 mg. The scientific evidence on the efficacy of intra-articular corticosteroids in the management of osteoarthritis is stronger in humans than in dogs. In humans they are mainly used in the acute inflammatory disease exacerbations. In horses corticosteroids are often administered together with hyaluronic acid. Hyaluronic acid is administered to restore the synovial fluid elastoviscosity and to reduce the pain caused by joint movement. Other potential effects are also being investigated. Hyaluronic acid preparations on the market in Finland or in the United States are not approved for intra-articular use in dogs. The dose of hyaluronic acid in the studies in dogs has ranged from 10 to 20 mg. The scientific proof of efficacy of hyaluronic acid is not strong in veterinary or human medicine. In human medicine the pain relieving-effect of hyaluronic acid has been suggested to be longer-lasting than that of corticosteroids. However, corticosteroids are preferred in states of acute inflammation. In horses hyaluronic acid is only rarely used as the only intra-articular medication. Other options for the intra-articular therapy of osteoarthritis include the mesenchymal stem cells, autologous conditioned serum, platelet-rich plasma and botulinum neurotoxin. Some of these are already in clinical use. None of the reviewed medications has a strong scientific evidence of efficacy. However, as the risks associated with intra-articular medications are in general rather small, intra-articular medications might in certain cases be worth trying. The review can be used when planning intra-articular corticosteroid or hyaluronic acid therapy for a canine patient.