A randomized blinded comparative study of clinical response to surface anatomy guided injection versus sonography guided injection of hyaloronic acid in patients with primary knee osteoarthritis.

BACKGROUND AND AIM

Comparison between the effect of sonographic guided and blind knee injection of hyaluronic acid has been evaluated in this study.

METHODS AND MATERIALS

Sixty-one patients with primary knee osteoarthritis were randomly allocated into two groups and received intrabursal injection of hyaloronic acid over 3 weeks. The difference between baseline amounts of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score and visual analogue scale (VAS) score and these amounts after 6 and 12 weeks were calculated and subsequently compared between the two groups.

RESULTS

Among all scores and indices, WOMAC pain and function subscales changed significantly (both in the short-term and long-term follow-up). The mean differences of WOMAC subscale pain in those who had received intra-articular injection under the guidance of sonography were significantly higher than those in patients who had received blind injections after 6 and 12 weeks. The mean differences of WOMAC subscale function in those who had received ultrasonography guided intra-articular injection were significantly higher than those in patients, who had received blind injections after 6 and 12 weeks. The mean in differences of the 10-cm VAS (both at rest and after 50-feet walk) in the two groups was statistically significant after 6 weeks, but did not remain significant after 12 weeks.

CONCLUSION

Application of sonography might improve the response of patients to intra-articular injection of hyaloronic acid, at least in certain clinical indices.