How effective are hyaluronic acid injections in relieving knee pain?

How effective are hyaluronic acid(HA) injections in relieving knee pain?

"Intra-articular viscosupplementation was moderately effective in relieving knee pain in patients with osteoarthritis at 5 to 7 and 8 to 10 weeks after the last injection but not at 15 to 22 weeks (Modawal et al, 2005)."

Reference:
Modawal A, Ferrer M, Choi HK, Castle JA. Hyaluronic acid injections relieve knee pain. J Fam Pract. 2005 Sep;54(9):758-67.


This study additionally included these practice recommendations:

"1. Consider injections of hyaluronic acid injections only after conservative therapy has been tried for atleast three months or the patient is unable to tolerate NSAIDS.
2. Stress to patients that pain relief may not be fully experienced until 5-7 weeks following the last injection."

What does this mean? HA injections should be tried after other treatment options have been explored. In addition, HA injections may offer moderate pain relief, but the pain relief can take up to a month to reach the maximum effect.

How much do HA injections cost? Each injection costs approximately $230 and the recommendations include patients receiving one injection per week for a total of five weeks which amounts to about $1150.