State of the art treatment of osteoarthritis (Proceedings)
Current treatment options for osteoarthritis are extensive and can be categorized into medical/ conservative or surgical therapies. Medical therapies may consist of weight control, exercise modification, rehabilitation therapy, pain management medications, oral joint protective compounds, and intra-articular treatments. Surgical options may include arthroscopic treatments, osteochondral autologous transplantation, osteotomies, regenerative stem cell therapy, or joint replacement. A multimodal management plan is a more progressive approach to the treatment of osteoarthritis and includes a combination of medical and potentially surgical options.
Oral Joint Modifying Agents
Joint protective compounds (JPCs) are commonly used in small animals. JPCs include both oral agents, specifically glucosamine, chondroitin sulfate, and avocado/soybean unsaponifiables (ASU), and injectable compounds, such as polysulfated glycosaminoglycan and hyaluronic acid.The administration of JPCs is indicated in a wide range of cases. JPCs may be used in animals with osteoarthritis or in healthy animals to help slow or protect against damage to the joint cartilage and synovium and to support the health of the tendons and ligaments. JPCs are often administered to working and performance dogs and should be considered in large breeds in general as well as in obese dogs due to the extra stress being placed on the joints. JPCs are also indicated when bone fractures involve the articulating surfaces or peri-operatively with surgical procedures involving the joint.
Glucosamine and chondroitin sulfate have been used in small animals since the mid 1990's. In vivo and in vitro research has demonstrated the compounds' efficacy. A rabbit instability model showed that a specific glucosamine hydrochloride and low molecular weight (LMW) chondroitin sulfate combination (Cosequin® , Nutramax Laboratories, Inc., Edgewood, MD) had a disease-modifying effect as administration slowed progression of cartilage degradation. In vitro the combination inhibited degradative enzymes. Results also demonstrated in vitro that the glucosamine and low molecular weight chondroitin sulfate synergistically stimulated proteoglycan production.
In a double-blind, placebo-controlled study in dogs, scintigraphic evaluation showed that pre-treatment with the specific glucosamine hydrochloride and LMW chondroitin sulfate combination protected against chymopapain-induced synovitis and the associated bone remodeling; treated dogs were also judged to be less lame. Dogs administered the same combination in a double-blind, placebo-controlled study using a cranial cruciate ligament transection model had less severe cartilage degradation and a return to a more normal physiologic state in the operated joint.
ASU has also been shown effective at supporting joint health. Recent international work in dogs indicates that this ingredient may have a positive effect on cartilage repair. While U.S. clinical trials in dogs and cats are in progress evaluating the use of an ASU/glucosamine hydrochloride/LMW chondroitin sulfate combination product (Dasuquin™, Nutramax Laboratories, Inc., Edgewood, MD), in vitro work strongly suggests that the three agents combined will produce excellent results. In IL-1β -stimulated canine chondrocytes, ASU, glucosamine hydrochloride, and LMW chondroitin sulfate reduced PGE2 levels by 80% versus activated controls. In feline chondrocytes, the combination also caused a significant reduction in PGE2 levels. Notably, the three agents together were shown more effective than just glucosamine and chondroitin sulfate at reducing expression of multiple inflammatory mediators in THP-1 cells, equine chondrocytes, and human chondrocytes.
Though JPCs may be used as part of a multimodal approach (with NSAIDs, weight reduction, exercise/rehabilitation therapy, and/or acupuncture), JPCs are often used alone especially for protection or in mild to moderate cases of OA, etc. In healthy animals for protection, an oral product may be given every other day with the dosage then adjusted as needed.
Polysulfated glycosaminoglycan (Adequan® Canine, Luitpold Pharmaceuticals, Inc., Shirley, NY) is primarily a chondroitin sulfate which can be administered intra-muscularly twice a week for up to 4 weeks. Adequan has been shown to decrease the amount of degradative enzymes which stimulate inflammation and cartilage erosion as well as promote repair and regeneration of cartilage. Clinical studies of Adequan have shown significant improvement in patients by the second or third injection with maximum benefit after the eight treatment. Clinical studies have also shown that 78.5 % of dogs that responded to Adequan® Canine were still improved six months later.