Multiple PRP > Single PRP > HA for Early Knee OA: Double-Blind RCT
Gormeli G · Knee Surg Sports Traumatol Arthrosc (2017)
DOI: 10.1007/s00167-015-3705-6This four-arm, double-blind RCT compared 3 PRP injections versus 1 PRP injection versus HA versus saline in 162 patients with early knee OA (KL grades 1-3). The study established a clear dose-response hierarchy: 3 PRP injections were significantly superior to all other groups, single PRP and HA were comparable to each other, and all active treatments beat saline. This is one of the few studies to directly test PRP dose-response within a single trial.
Clinical Relevance
Directly informs clinical protocol design: a series of 3 PRP injections is superior to a single injection for knee OA. Clinicians who offer single PRP injections may be undertreating patients. This supports the common protocol of 3 weekly injections.
Key Takeaways
- 3 PRP injections > 1 PRP injection > saline (clear dose-response)
- Single PRP approximately equal to HA
- All active treatments superior to saline placebo
- 162 patients across 4 arms (well-powered)
- Double-blind design adds rigor
- Establishes that multiple injections produce better outcomes than single injections for knee OA
Key Findings
4-arm: 3xPRP vs 1xPRP vs HA vs saline. Multiple PRP (3x) significantly superior to all groups. Single PRP ~ HA, both > saline. DOSE-RESPONSE confirmed.
Clinical Context
Study Design
Randomized Controlled Trial (Double-Blind, 4-Arm)
Condition
Early Knee OA (KL Grade 1-3)
Sample Size
162 patients
Follow-up
6 months
Control Group
Single HA, Saline placebo
Primary Outcome
IKDC, EQ-VAS
PRP Protocol & Intervention
Injection Interval
Weekly