Background: Intra-articular injections of hyaluronans have been
shown to be safe and effective for the treatment of pain associated with
osteoarthritis of the knee. This pilot study was undertaken to gather
preliminary data on the efficacy and safety of five weekly intra-articular
injections of Hyalgan (sodium hyaluronate; molecular weight, 500 to 730 kDa)
as compared with saline solution for the treatment of pain associated with
osteoarthritis of the ankle.
Methods: Twenty patients at two test sites were randomized
with use of a double-blind (blinded observer), saline solution-controlled,
parallel experimental design. Patients were randomized to receive five weekly
intra-articular injections of either 1 mL of sodium hyaluronate (10 mg/mL) or
1 mL of phosphate-buffered saline solution into the ankle joint. The primary
outcome measurement was the ankle osteoarthritis score. Several secondary
outcome measures also were assessed.
Results: Significant improvement in the mean ankle osteoarthritis
score from baseline was seen at all follow-up visits from one to six months in
both the sodium hyaluronate group and the saline solution group (p <
0.0001). In addition, five of nine patients in the sodium hyaluronate group
had >30 mm of improvement in this score, compared with one of eight
patients in the control group. No withdrawals were directly attributable to
the injections of sodium hyaluronate or saline solution, and no severe
medication-related adverse events were observed.
Conclusions: The present study suggests that five weekly
intra-articular injections of sodium hyaluronate (molecular weight, 500 to 730
kDa) are well tolerated, can provide sustained relief of pain, and can improve
function in patients with osteoarthritis of the ankle. These findings are
consistent with those of previously published studies involving
intra-articular injections of sodium hyaluronate in other joints, but they
require confirmation in a large, randomized, saline solution-controlled
Level of Evidence: Therapeutic Level I. See Instructions
to Authors for a complete description of levels of evidence.