The aims of this study were (1) to perform a systematic review of meta-analyses evaluating platelet-rich plasma (PRP) injection in the treatment of knee joint cartilage degenerative pathology, (2) to provide a framework for analysis and interpretation of the best available evidence to provide recommendations for use (or lack thereof) of PRP in the setting of knee osteoarthritis (OA), and (3) to identify literature gaps where continued investigation would be suggested.
Literature searches were performed for meta-analyses examining use of PRP versus corticosteroids, hyaluronic acid, oral nonsteroidal anti-inflammatory drugs, or placebo. Clinical data were extracted, and meta-analysis quality was assessed. The Jadad algorithm was applied to determine meta-analyses that provided the highest level of evidence.
Three meta-analyses met the eligibility criteria and ranged in quality from Level II to Level IV evidence. All studies compared outcomes of treatment with intra-articular platelet-rich plasma (IA-PRP) versus control (intra-articular hyaluronic acid or intra-articular placebo). Use of PRP led to significant improvements in patient outcomes at 6 months after injection, and these improvements were seen starting at 2 months and were maintained for up to 12 months. It is unclear if the use of multiple PRP injections, the double-spinning technique, or activating agents leads to better outcomes. Patients with less radiographic evidence of arthritis benefit more from PRP treatment. The use of multiple PRP injections may increase the risk of self-limited local adverse reactions. After application of the Jadad algorithm, 3 concordant high-quality meta-analyses were selected and all showed that IA-PRP provided clinically relevant improvements in pain and function compared with the control treatment.
Level IV, systematic review of Level II through IV studies.
IA-PRP is a viable treatment for knee OA and has the potential to lead to symptomatic relief for up to 12 months. There appears to be an increased risk of local adverse reactions after multiple PRP injections. IA-PRP offers better symptomatic relief to patients with early knee degenerative changes, and its use should be considered in patients with knee OA.