OA, also known as degenerative
joint disease, is the most common form of
arthritis in the United States, affecting 54.4 million, or 22.7% of the adult population. The knee is the most common joint affected in OA, with up to 41% involvement, 30% in the hands, and 19% in the hips. The pathophysiology of OA is complex, with contributing factors including mechanical stress to the joint, as well as many person-specific factors such as
genetic susceptibility, ethnicity, nutrition, and sex. Treatment modalities include weight control, exercise, non-steroidal and steroidal anti-inflammatory drugs,
opioids, intra-articular platelet-rich plasma, placebo,
corticosteroid injection, intra-articular viscosupplementation, and surgery.
Viscosupplementation consists of injection of
hyaluronic acid (HA) into affected joints, intending to restore the physiologic viscoelasticity in the synovial fluid (SF) in the absence of
inflammation. HA has also been shown to downregulate pro-inflammatory factors, such as
PGE2 and NFkB, and
proteases and
proteinases known to break down the joint matrix.The
contraindications for HA injection are similar to any other injection
therapy, and adverse events are usually mild, local, and transient.
Viscosupplementation (VS) is effective over placebo and more effective than
NSAIDs and
corticosteroids in
pain reduction and improved functionality; however, guidelines recommend neither for nor against its use, demonstrating variability in the existing evidence base.Current VS options divide primarily into native vs. cross-linked and low-molecular-weight vs. high-molecular-weight. Current treatment options include
Hylan g-f-20,
Sodium Hyaluronate preparations (Suparts Fx, Euflexxa, Gelsyn-3, Durolane, Hyalgen), single-use agents (Gel-One,
Synvisc-One, Monovisc), and
Hyaluronan (
Orthovisc, Monovisc, Hymovic). They share a common safety profile, and all have evidence supporting their efficacy. Their specific details are reviewed here.
SUMMARY: OA is the most common form of
arthritis. It is a chronic, debilitating illness with a high impact on the functionality and quality of life of a significant part of the population in the western world. Treatments include medical management,
physical therapy, activity modification, injection, and surgery. VS effectively reduces
pain, increases functionality, and delays surgery in the knee to treat
osteoarthritis. While previous studies have demonstrated variable results, more evidence is becoming available generally supportive of the benefit of VS in the treatment of knee OA.