Does PRP Actually Work, and Where Doesn't It?
A surgeon's account of PRP: the conditions where trial evidence is genuinely strong, the negative trials that get left out of most marketing, and where he draws the line on offering it.
Overview
Platelet-rich plasma is a concentrate of a patient's own platelets, spun down from a blood draw and injected into a joint or tendon to stimulate a healing response. It works reasonably well for some conditions and not at all for others, and the two negative results that matter most — no cartilage benefit for knee arthritis and no advantage over saline for cuff tendinopathy — are rarely mentioned on pages selling the treatment. This page states where the evidence holds up and where it does not.
Who this is for
PRP is worth discussing for patients with mild-to-moderate knee osteoarthritis who have not gotten adequate relief from activity modification and physical therapy, for chronic tendon conditions like lateral epicondylitis and plantar fasciitis that have failed a reasonable course of conservative care, and as an intraoperative adjunct during certain rotator cuff repairs. It is not a serious option for advanced, bone-on-bone arthritis, and it is not a reliable standalone treatment for chronic rotator cuff tendinopathy, where the best available placebo-controlled trial found no benefit. Patients hoping PRP will let them avoid a needed structural operation — a torn tendon that requires repair, a joint that requires replacement — are not good candidates for it as a substitute.
How I approach it
I lead with the negative trials because most PRP marketing doesn't, and patients deserve to make this decision with the full picture. The RESTORE trial randomized 288 patients with knee osteoarthritis to a single PRP injection or a saline placebo and found no difference in medial tibial cartilage volume on MRI at 12 months — PRP did not preserve or rebuild cartilage in this rigorously designed trial (Bennell et al., JAMA 2021). Separately, a double-blind RCT of PRP against saline for chronic rotator cuff tendinopathy found no statistically significant difference at any time point through one year (Kesikburun et al., AJSM 2013). I tell patients about both studies before I discuss anything PRP does well, because a treatment that only sounds good when you omit its failures isn't one I want to sell.
Where I do use PRP is narrower and, I think, better supported. For knee osteoarthritis pain, meta-analyses comparing PRP against hyaluronic acid injections found PRP statistically superior on pain and function scores at both 6 and 12 months (Dai et al., Arthroscopy 2017; Shen et al., AJSM 2017). I present that as a pain and function benefit, not a disease-modifying one — the RESTORE data make clear it is not rebuilding the joint. For lateral epicondylitis, a randomized trial with two-year follow-up found PRP produced an ongoing advantage over corticosteroid injection, whereas the corticosteroid group's early gains faded (Gosens et al., AJSM 2011). I use that same durability logic with plantar fasciitis patients who have already tried and lost benefit from a steroid shot.
Formulation matters more than most PRP discussions acknowledge. Leukocyte content, platelet concentration, and whether the plasma is activated before injection all vary by device and by protocol, and these differences plausibly explain some of the conflicting results across trials. I don't treat PRP as a single uniform product, and I tell patients that a positive trial for one formulation and injection target doesn't automatically transfer to a different tendon or joint.
Where Surgeons Disagree
Is a single PRP injection enough, or does a series matter?
For knee osteoarthritis, I favor a series over a single injection where the goal is pain and function benefit.
A meta-analysis of 10 RCTs for knee osteoarthritis found that multiple injections produced significantly better outcomes than a single dose, with the pooled data favoring a series of two to three injections (Dai et al., Arthroscopy 2017). That said, RESTORE — the trial with the cleanest placebo control — used a single injection and still found a pain benefit over saline, just no cartilage benefit (Bennell et al., JAMA 2021), so a single injection is not without value; it is a question of degree.
Where I’d be talked out of it
In a patient for whom cost is a genuine barrier and who wants to test whether PRP helps them at all before committing to a full series, a single injection is a reasonable and defensible starting point. I don't insist on a three-injection series as a condition of treating someone.
Should PRP be offered for chronic rotator cuff tendinopathy without a structural tear?
I am cautious here and say so directly — this is one of the weaker parts of the PRP evidence base.
The most rigorous placebo-controlled trial in this specific population — chronic supraspinatus tendinopathy without a full-thickness tear — found no statistically significant advantage of PRP over a saline injection at any time point through 12 months (Kesikburun et al., AJSM 2013). Other analyses comparing PRP against corticosteroid injection for shoulder tendinopathy have found PRP favorable at 12 months (Hurley et al., Arthroscopy 2021 — the specific numeric findings in this analysis could not be independently verified from an accessible source, so I cite it only for its existence in the published literature), but a positive result against corticosteroid is a different claim than a positive result against placebo, and the placebo comparison is the one that tells you what the drug itself is doing.
Where I’d be talked out of it
A patient who has failed physical therapy, doesn't want a corticosteroid injection near the tendon because of tissue-quality concerns, and understands the placebo-controlled evidence is negative may still reasonably choose to try PRP given its low risk profile. I'll perform it in that circumstance, but only after stating the Kesikburun result plainly.
Risks and honest tradeoffs
Because PRP is made from a patient's own blood, the risk profile is favorable compared with a foreign injectable: there is no meaningful risk of allergic reaction or disease transmission. The real risks are a temporary increase in pain and stiffness for a few days after injection, a small risk of local infection from any needle procedure, and, more significantly, the practical risk of paying out of pocket for a treatment that may not work for a given patient. PRP is classified as investigational by most commercial insurers, Medicare, and Medicaid, so it is not typically a covered benefit, and patients should confirm their specific coverage before treatment rather than assume it is included. Patients on certain blood thinners may not be good candidates, since some anticoagulants affect platelet function and the quality of the concentrate that can be produced; this needs to be discussed individually with the prescribing physician.
Alternatives I considered
For knee osteoarthritis pain, a corticosteroid injection remains a faster-acting and typically insurance-covered alternative, though its benefit tends to fade within a few months where PRP's benefit, in patients who respond, can extend further. For tendon conditions like lateral epicondylitis, a course of eccentric-loading physical therapy is a reasonable first step before any injection, and many patients improve enough that PRP is never needed. I do not offer PRP as an alternative to a structural repair in a patient with a full-thickness rotator cuff tear or a torn tendon that requires surgical reattachment — a torn structure needs to be fixed, and no injection changes that mechanical fact.
Biologics used
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Frequently Asked Questions
Clinical References
- Bennell KL, Paterson KL, Metcalf BR, et al. Effect of intra-articular platelet-rich plasma vs placebo injection on pain and medial tibial cartilage volume in patients with knee osteoarthritis: the RESTORE randomized clinical trial. JAMA. 2021;326(20):2021-2030.
- Kesikburun S, Tan AK, Yilmaz B, Yaşar E, Yazicioğlu K. Platelet-rich plasma injections in the treatment of chronic rotator cuff tendinopathy: a randomized controlled trial with 1-year follow-up. Am J Sports Med. 2013;41(11):2609-2616.
- Dai WL, Zhou AG, Zhang H, Zhang J. Efficacy of platelet-rich plasma in the treatment of knee osteoarthritis: a meta-analysis of randomized controlled trials. Arthroscopy. 2017;33(3):659-670.
- Shen L, Yuan T, Chen S, et al. The temporal effect of platelet-rich plasma on pain and physical function in the treatment of knee osteoarthritis: systematic review and meta-analysis of randomized controlled trials. Am J Sports Med. 2017;45(11):2708-2719.
- Gosens T, Peerbooms JC, van Laar W, den Oudsten BL. Ongoing positive effect of platelet-rich plasma versus corticosteroid injection in lateral epicondylitis: a double-blind randomized controlled trial with 2-year follow-up. Am J Sports Med. 2011;39(6):1200-1208.
- Hurley ET, Lim Fat D, Moran CJ, Mullett H. The efficacy of platelet-rich plasma and platelet-rich fibrin in arthroscopic rotator cuff repair: a meta-analysis of randomized controlled trials. Arthroscopy. 2021;37(3):753-762.
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