Objective: Aim of this trial was to compare efficacy of activated platelet-rich plasma against hyaluronic acid as intra-articular injections to people with osteoarthritis of the knee.
Design: Phase-2 randomized controlled trial, with blind patients and outcome assessors.
Setting: Outpatient rehabilitation service; years 2011-2013.
Subjects: Patients with knee osteoarthritis grades 2-3 at magnetic resonance imaging (MRI) were included after consent and randomized. Target sample size was 25 patients per group.
Interventions: Patients received three activated platelet-rich plasma (intervention group) or hyaluronic acid (controls) intra-articular injections at 4-week intervals.
Main measures: Main outcome measure was proportion of patients with >1 grade improvement at six months from last injection, as assessed by a radiologist blind to study group. Patients were evaluated over time clinically and with functional scales (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lysholm, Tegner, American Knee Society Score (AKSS), Lequesne, visual analogue scale (VAS) for pain).
Results: Overall, 30 patients were randomized to intervention and 28 to control group. For primary outcome, 28 patients (29 knees) in the intervention and 22 (25 knees) in the control group were available. Patients with at least 1 grade improvement at repeat MRI were 14 (48.3%) in the intervention and 2 (8%) in the control group ( P < 0.003). Improvement in symptoms and functional scales was consistently higher in the intervention group. No side-effects were observed in either group.
Conclusion: Activated platelet-rich plasma reduces articular damage as evident at MRI, as soon as six months after treatment; it reduces pain and improves patient's function and overall quality of life.
Keywords: Osteoarthritis of the knee; platelet-derived growth factors; randomized controlled trial.