Injectable medications for osteoarthritis.

Osteoarthritis is one of the most frequent and chronic conditions that affect the U.S. population. Use of intra-articular injections is one of the established treatment options available in the nonoperative care for the management of symptomatic osteoarthritis. Common injectable medications include corticosteroids, hyaluronic acid, and other less traditional compounds (for example, botulinum toxin). Corticosteroids work by anti-inflammatory and antinociceptive actions. Corticosteroids have been shown to decrease pain and symptoms associated with osteoarthritis for up to 3 weeks. Hyaluronic acid has an unclear mechanism of action, but it is thought to promote the restoration of hyaluronic acid within an osteoarthritic joint. The efficacy of hyaluronic acid is modest and is most beneficial between 5 and 13 weeks after treatment. Other injectable compounds have been studied and include botulinum toxin type A, which has been theorized to work as an antinociceptive agent. One must be aware of the potential adverse effects associated with these medications. For all of these injectable treatments, the placebo effect must not be overlooked, because it has be demonstrated in multiple studies that these medications provide similar relief of pain when compared with placebo. Image guidance with ultrasound or fluoroscopy may be considered when performing intra-articular injections to improve accurate placement of medication.