What Is Viscosupplementation?

Treatment Option for Knee Osteoarthritis

Knee injection
MedicalRF.com/Getty Images

Viscosupplementation is a treatment that involves the injection of gel-like substances (hyaluronates) into a joint to supplement the viscous properties of synovial fluid. In a normal joint, synovial fluid (which naturally contains hyaluronic acid) helps to cushion the joint and provides lubrication to reduce friction which occurs with movement of the joint. In a joint affected by osteoarthritis, there is deterioration of cartilage, the tissue that covers the ends of the bones in a joint.

Also, with osteoarthritis, synovial fluid loses its ability to lubricate. The result is joint pain, stiffness, and limited range of motion.

Hyaluronate injections were developed as a way to supplement the affected joint, compensating for lost properties which occur with joint damage from osteoarthritis. Hyaluronates have been approved by the U.S. FDA for the treatment of osteoarthritis of the knee in patients who have failed to respond to conservative treatment options (e.g., physical therapy and exercise, hot or cold applications, weight loss, use of a cane or knee support, pain relievers, or intra-articular steroid injection). Hyaluronates have not been approved for use in joints other than the knee, but that has been investigated.

Viscosupplementation has been studied as a treatment option for osteoarthritis since the 1970s. It was first used in Europe and Asia. Hyaluronate injections are considered a treatment; they are not classified as drugs.

There are several viscosupplements which have been approved by the U.S. FDA, with the first one approved in 1997.  The following dates indicate when each viscusupplement was approved by the FDA:

The older viscosupplements require a series of 3 to 5 injections administered one week apart.

Newer versions were developed as single injections (e.g. Synvisc-One and Monovisc). The injections are not helpful for all patients who try them. Of patients who do obtain some relief from the hyaluronate injections, pain relief is greatest at 8 to 12 weeks after receiving the first injection. The duration of pain relief is also variable. Some patients have reported relief that lasted more than 6 months. 

That said, studies of viscosupplementation have not confirmed that it significantly reduces pain or improves joint function. While a Cochrane Review concluded that viscosupplementation is more effective than placebo, other studies did not associate the injections with significant pain relief.

If a patient does achieve a successful outcome which lasts for several months, the viscosupplementation can be repeated (usually 6 months later). It is thought that patients in early stages of knee osteoarthritis, rather than advanced stages, have the best chance of obtaining a good result from viscosupplementation.

Common side effects associated with viscosupplementation include temporary injection site pain, local swelling, heat, redness, rash, itching, bruising, or an accumulation of fluid in the injected joint.

Typically, the side effects are mild and of short duration. Serious reactions are considered rare, but may include allergic reaction, infection, or bleeding.


Treatments and Procedures.  Viscosupplementation. The Cleveland Clinic. 11/04/2014.

Viscosupplementation Treatment for Knee Arthritis. OrthoInfo. American Academy of Orthopaedic Surgeons (AAOS). June 2015.

Cochrane in CORR®: Viscosupplementation for the Treatment of Osteoarthritis of the Knee. Clinical Orthopaedics and Related Research. 2014 July.

Continue Reading