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.