Orthovisc vs Synvisc: Knee osteoarthritis Treatment
- Medical Community Member - September 14th 2018
- General Public
If your patient is considering using hyaluronic acid injections to alleviate the pain and swelling that comes with knee osteoarthritis, finding a product that meets their therapeutic needs is of paramount importance. With so many choices currently available, it is an undoubtedly difficult process to find the right filler. Because of this, this article will provide details on two popular hyaluronic acid products: Orthovisc and Synvisc. This exploration of these fillers will help you and your patient select the right treatment for them.
Knee osteoarthritis and the role of hyaluronic acid
Osteoarthritis of the knee is a painful degenerative condition of the knee joint in which the gradual breakdown of the protective cartilage around the ends of the bones leads to damage and the gradual destruction of the joint, causing symptoms of inflammation, stiffness, and pain. Patients with this disease suffer from limited mobility that often interferes with daily activities. Typical strategies to cope with this progressive, degenerative disease involves the use of analgesics, physical therapy, weight loss management, or a combination of the above.
A critical component in the development of osteoarthritis is synovial fluid, the thick, viscous liquid found in synovial joints like the knees and is responsible for the lubrication and cushioning of the joint bones. Synovial fluid is primarily made up of hyaluronic acid, and it is this compound that provides synovial fluid with its highly viscoelastic properties. In people with knee osteoarthritis, the quantity and sizes of the hyaluronic acid molecules in synovial fluid are both reduced, resulting in rheological changes to the fluid itself. The fluid becomes thinner and more watery, reducing its ability to lubricate and cushion the joint.
Orthovisc and Synvisc as viscosupplements
Viscosupplementation is a type of therapy that addresses the diminished amount of hyaluronic acid in synovial fluid by supplementing the (degraded) synovial fluid in the diseased joint with a hyaluronic acid product that possesses the rheological properties of healthy synovial fluid. These medications are normally offered as second-line therapies, which are medications and treatments that are used after the patient has not adequately responded to the primary treatments of a condition, which in this case are pain medication and physical therapy. Viscosupplement preparations differ significantly in their molecular weight, concentration, rheological properties, manufacturing processes, and residence times in the joint.
The effects that viscosupplements confer is delayed but long-lasting. While it can sometimes take weeks or even several months for the full results of viscosupplements, including Orthovisc and Synvisc, to materialize, each of these medications can provide up to six months of improvement, including reduced pain and greater range of motion. As a pharmaceutical class, viscosupplements have been widely studied and have been consistently shown to be safe and effective for the treatment of knee osteoarthritis. Viscosupplements are widely used and accepted by many doctors and medical practitioners.
Differences between Orthovisc and Synvisc
- Composition: Synvisc is made of a complex of reticulated hylan, hylan A and hylan B. Hylan A is a soluble, high-molecular-weight molecule that makes up 80% of the complex, while hylan B is an insoluble gel-like continuous molecular network that makes up the remaining 20% of the complex. Orthovisc, on the other hand, comprises cross-linked, high-molecular-weight hyaluronan.
- Viscoelastic properties: Synvisc has viscoelastic properties that are more similar to those of the synovial fluid of young and healthy adults. This has an effect in how effective the product is in providing lubrication and shock-absorption.
- Clinical outcomes: Researchers examined the differences in clinical and cost outcomes among different viscosupplements and found that Synvisc had a reduced effect in respect to delaying time to knee replacement surgery when compared to other products, including Orthovisc.
- Hyaluronan sources: While Synvisc is made from rooster/chicken combs, the hyaluronic acid used in Orthovisc is derived from bacterial cells. A study by Petrella et al. found evidence suggesting that products with non-avian-derived hyaluronic acid have a lower risk of causing side effects when compared to products with hyaluronic acid derived from avian sources.
- Adverse event profile: Synvisc is associated with greater incidences of acute local reactions, an occurrence that is not seen with treatment using other viscosupplements, including Orthovisc. These reactions seem to increase in frequency with repeated treatments. The incidence of acute local reactions with Synvisc treatment may be attributed to the process used to manufacture the product, which involves using chemical divinyl sulfone and formaldehyde to crosslink the native hyaluronan. These chemicals may provoke an immunological tissue reaction, leading to pseudosepsis.
Hyaluronic acid viscosupplement injections are a safe and efficacious way to help patients treat and manage their knee osteoarthritis symptoms in the long term. While Synvisc and Orthovisc are both effective and safe viscosupplements, they have considerable differences with regard to their respective adverse event profile, product composition. and clinical outcomes. Patients should always consult a knowledgeable medical practitioner when deciding which of these products, or any aesthetic filler product for that matter, is the right one for them.