Hyaluronic acid (HA) and platelet-rich plasma (PRP) are two treatment options used for knee osteoarthritis (KOA) but studies comparing the efficacy of the two yield conflicting results. In addition, the association of clinical outcomes of PRP intra-articular injections with changes in the ultrasonography structural appearance of the knee has not been investigated.
To compare the efficacy of PRP and HA intra-articular injections as mono-therapeutic options for primary KOA, and to determine whether the clinical outcomes are associated with changes in the ultrasonography structural appearance.
A randomized clinical trial was conducted on 89 patients with KOA. The patients were given either PRP (n = 45) or HA (n = 44) intra-articular injections. The patients received three injections in the knee, which was more symptomatic at baseline evaluation, with a 2-week interval between injections. The outcome measures included visual analog score - pain, International Knee Documentation Committee Score, and assessment of synovial hypertrophy, synovial vascularity and knee effusion using ultrasonography. Outcome measures were assessed at baseline and at 3 and 6 months post-injection.
While both PRP and HA injections resulted in the improvement of all outcome measures at 3 and 6 months follow up, they were significantly better in the PRP group than in the HA group.
Intra-articular injection of PRP is an effective treatment that reduced pain and improved functional status in patients with KOA. The clinical outcomes of the intra-articular injections of PRP are associated with improved synovial hypertrophy and vascularity scores, and less effusion.