ITalkHorses.com
Current Therapies for Osteoarthritis
With each breed and discipline come varying predispositions to lameness issues. Degenerative joint disease (DID, arthritis, osteoarthritis) is an ailment that does not discriminate. Repeated trauma, daily wear and tear, or even an acute traumatic incidence, results in detrimental inflammation, and subsequent changes in joint structure and function. There is an ever expanding repertoire of treatment modalities marketed for DJD. These include oral, systemic (intravenous or intramuscular) and intra-articular treatments. Typically, a combination of the aforementioned modalities tailored to your horse's specific needs, provides the most benefit. While the majority of conventional treatments for DJD are aimed at decreasing joint pain and inflammation, novel products are being researched and developed to help slow the progression of disease and promote healing of the arthritic joint.
Glucosamine sulfate containing oral supplements are readily available and widely used in the equine industry as a non-invasive treatment and preventative for arthritis. It is thought to have anti-inflammatory effects while proving substrates or building blocks for synovial fluid production. Recently, questions have been raised about the ability of horses to absorb the drug from the gut, especially in high enough concentrations to reach the joint and exert an affect. While experimental data is lacking to prove the efficacy of these products, anecdotal evidence is abundant. Furthermore, human controlled studies have shown decreased pain and increased range of motion in arthritic patients receiving oral glucosamine. IN view of the non-invasive nature of this therapy, it remains a good first line treatment of mild cases of DJD, or an adjunctive therapy for more advance cases.
Mysistol is a unique joint supplement in that is combines glucosamine hydrochloride with cetyl myristoleate, a a fatty acid that has been shown to decrease pain and inflammation in arthritic joints. Cetyl myristoleate was originally developed for humans suffering from rheumatoid arthritis. Myristol also has therapeutic levels MSN for anti-inflammatory effect, collagen for tendon and ligament repair and ascorbic acid for increased absorption. Our clinic has seen positive results with this product, extending the period of time between intra-articular injections and improving soundness.
Intravenous sodium hyaluronate (Legend by Bayer) is commonly employed treatment for degenerative joint disease with synovitis (inflammation of the joint capsule). Hyaluronic acid is a natural component of synovial fluid and as a result, the medication acts to promote joint lubrication. It is also know to have anti-inflammatory affects within the diseased joint . The medication is typically given at a loading dose intially (1 vial IV once a weekly for 3-4 weeks), followed by a maintenace dose of 1 vial once monthly. Adequan is a polysulfated glycosaminoglycan (PSGAG) and is known to have chondroprotective effects, preventing, attenuating, and even reversing cartilage lesions associated with DJD. Adequan is known to inhibit cytokines, prostaglandins and metalloproteinases, all fo which are key mediator of inflammation. One vial is administered IM every 4 days for eight treatments, by a maintenance schedule of 1 vial once monthly. Adequan can also be administered directly into the joint for certain cases.
Intra-articular medications are deposited directly within the diseased joint, thereby making this modality the most direct and in some cases, most efficacious treatment modality. Corticosteroids including triamcinolone and methylprednisolone acetate are administered using sterile technique, after careful aseptic preparation of the joint. Steroids act at specific receptors to inhibit inflammatory mediators within the joint. Inflammation in and of itself is extremely detrimental to joint health, and as a result, attenuation of inflammatory mediator by corticosteroids, although not curative, can help to slow the progression of degenerative joint disease. Hyaluronic acid (i.e. Hylartin V) is often time delivered in conjunction with steroids, which again works to decrease inflammation and increase the viscosity of lubrication affect of joint fluid. With decreased inflammation comes a pain relieving affect, thereby improving performance in many cases. Steroids do have negative affects on cartilage, and as a result, judicious use of low doses is indicated.
Experimental and anecdotal evidence exists for the efficacy of shockwave therapy in the treatment of osteoarthritis. Shockwave therapy acts to stimulate blood-flow to the diseased joint, thereby increasing the delivery of mesenchymal cells for healing. Treatment schedule vary by case, but typically entail a series of three treatments scheduled 2-3 weeks apart.
Novel biologic therapies are being developed and marketed for the treatment of osteoarthritis. IRAP (Interleukin - 1 Receptor Antagonist) targets a key mediator of joint inflammation (Interleukin - 1), by competitively binding its receptor and inhibiting its affects. The protein is isolated from the patient's own serum, and then injected directly into the joint using sterile technique. Stem cells harvested from either adipose (fat) cells or bone marrow is efficacious in certain cased of osteoarthritis, however this may be more useful for joints in which soft tissue (i.e. ligamentous) injury exists or those cases which are refractory to intro-articular steroid administration.
Non-steroidal anti-inflammatory drugs (NSAID's) such as Bute and Banamine are effective at decreasing pain and inflammation. However, they carry with them the potential for negative side effects on the kidneys and gastrointestinal tract. Therefore, it is important to use these medications judiciously in conjunction with the above described treatment modalities, so as to decrease the frequency and dose required. Bute is particularly useful during "flare ups" or immediately prior to intense exercise that may exacerbate pre-existing joint conditions. Diclofenac cream (Surpass) is a topical NSAID that is applied directly over the affected joint. It penetrates through the skin to reach therapeutic concentrations within the joint. Studies have shown its effects to be comparable to those of orally administered Bute, however, systemic absorption is minimal and negative side effects vastly diminished. It is important to remember that Surpass can penetrate only millimeters of skin, so it is not useful for every joint. Hocks and knees affected by DJD are conducive to treatment with Surpass.
This is a very brief overview of the various treatment options available for degenerative joint disease. It is important to work with you veterinarian to develop a suitable treatment regimen for you horse based on his or her specific needs.
- Wendy Simmons, DVM
Block and Bridle Veterinary Service
32649 WCR 53
http://www.blockandbridlevets.com/