Viscosupplementation is a medical procedure involving the injection of a gel-like substance, typically hyaluronic acid, directly into a joint. This non-surgical treatment aims to lubricate and cushion the joint. It is a minimally invasive treatment for joint discomfort.
How Viscosupplementation Works
Hyaluronic acid (HA) is a naturally occurring high-viscosity polysaccharide found in the body, particularly within the synovial fluid of joints. This fluid acts as a lubricant and shock absorber, allowing bones to glide smoothly over each other. In conditions like osteoarthritis, the concentration and molecular weight of hyaluronic acid in the synovial fluid can decrease, leading to increased friction and reduced cushioning.
Viscosupplementation introduces hyaluronic acid into the affected joint, aiming to restore the fluid’s properties. This supplemental HA improves joint lubrication and shock absorption. Beyond mechanical functions, hyaluronic acid also has biochemical effects, helping to reduce inflammation and the activity of enzymes linked to osteoarthritis. It can also stimulate the natural production of hyaluronic acid by the body’s own cells within the joint.
Patient Experiences and Reported Efficacy
Patients frequently report a noticeable reduction in joint pain following viscosupplementation. This pain relief is often accompanied by improved joint function and increased mobility, allowing individuals to engage more easily in daily activities and gain greater independence.
Clinical studies support these subjective reports of efficacy. A meta-analysis published in Osteoarthritis and Cartilage found that patients receiving hyaluronic acid injections experienced improvements in pain relief and joint mobility compared to placebo groups. Some research indicates that viscosupplementation can lead to pain relief lasting several months, sometimes up to six months or longer. While the onset of relief may be slower than with corticosteroid injections, often taking several weeks, the effects may last for a more extended period.
Individual responses to viscosupplementation can vary. While many patients experience positive outcomes, some may not see significant improvement. Effectiveness can be influenced by factors like the stage of osteoarthritis, often being most effective in mild to moderate cases. Despite varying results across studies, a 2006 Cochrane Review, which included 76 trials, supported the efficacy of viscosupplementation against placebo, reporting beneficial effects on pain, physical function, and global assessment. The strongest findings were observed between 5-13 weeks post-injection.
Commonly Reported Side Effects
Viscosupplementation is considered a safe procedure, but patients may experience some side effects localized to the injection site. The most common reactions include mild pain, soreness, warmth, and slight swelling immediately following the injection. These symptoms are temporary, resolving within one to two days, and can be managed with rest and ice packs.
A less common, but more pronounced, reaction is an “injection flare,” which occurs in approximately 1% of patients. This involves a temporary increase in pain and swelling at the injection site that can be significant. While uncomfortable, these symptoms typically subside within a few days, and a healthcare provider can manage them.
More serious complications are rare but can include local allergic reactions, such as redness, itching, or difficulty breathing. Infection and bleeding at the injection site are also rare risks. Patients with known hypersensitivity to hyaluronic acid products or active local infections in the joint should not receive these injections.
Determining Candidacy for Treatment
Viscosupplementation is considered for individuals with mild to moderate osteoarthritis, especially when other conservative treatments have not provided sufficient relief. These prior treatments may include over-the-counter pain relievers, physical therapy, or corticosteroid injections. It is most commonly performed in the knee, but also used in other joints like the hip, shoulder, and ankle.
An evaluation of the grade of osteoarthritis, often through radiographic imaging, helps determine candidacy. Patients with severe joint deformity, advanced osteoarthritis (e.g., Kellgren-Lawrence grade 4), or joint destruction are not typically considered candidates. Most hyaluronic acid preparations are derived from chicken or rooster combs, so individuals with egg or poultry allergies should discuss this with their doctor, as some products are safe for those with such allergies.