What to ask when studies disagree about PRP

Ask what happened after the other shot

A salt-water shot is used for comparison; it isn't the treatment being sold. One group gets PRP, while another group gets salt water in the sore joint. Researchers then compare pain and joint use in both groups. If both groups improve by about the same amount, PRP didn't add clear relief in that study. Other studies have reported more relief with PRP. Ask if the research covered your joint and about the same amount of wear.

A study fits better when its patients resemble the person asking about care.

Decide what useful relief would mean

Before paying, name one change that would matter in daily life. It might be sleeping longer, walking farther, or reaching a shelf. Ask when people tend to notice relief and whether it lasts. The studies can't promise that exact change. They can show what happened to groups of people. If the clinic gives a firm success claim, ask for the medical work behind it.

Relief matters when it changes an ordinary task.

Use knee findings only for a similar knee

The most helpful PRP studies have mainly looked at knees with early or middle wear. Those findings don't settle what happens in a hip, shoulder, elbow, or back. A badly worn knee may also respond differently from one with less wear. An exam and earlier X-rays show whether the research is close to your case. Ask the clinic to say where the match is good and where it isn't.

Uncertain research belongs in the talk about both relief and cost.

Sources

1. RESTORE, the largest and most rigorously blinded placebo-controlled PRP trial in knee OA (n=288, participant-, injector- and assessor-blinded), gave three weekly injections of a commercial leukocyte-poor PRP or saline. At 12 months the change in knee pain was -2.1 vs -1.8 points (difference -0.4; 95% CI -0.9 to 0.2; P=.17) and the change in medial tibial cartilage volume was -1.4% vs -1.2% (difference -0.2%; P=.81). Twenty-nine of 31 prespecified secondary outcomes showed no between-group difference. The authors concluded the findings do not support the use of PRP for knee OA.

   Bennell KL, 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. DOI: 10.1001/jama.2021.19415.

2. A Bayesian network meta-analysis of 48 Level I-II randomized trials (9,338 knees) with a minimum 6-month follow-up ranked the four commonest intra-articular injections. HA and PRP both significantly improved pain versus placebo; HA, PRP and BMAC all significantly improved function versus placebo. SUCRA rankings were PRP 91.54, BMAC 76.46, HA 53.12, corticosteroid 15.18 and placebo 13.70 - corticosteroid ranked barely above placebo at six months and beyond.

   Jawanda H, et al. — Platelet-Rich Plasma, Bone Marrow Aspirate Concentrate, and Hyaluronic Acid Injections Outperform Corticosteroids in Pain and Function Scores at a Minimum of 6 Months as Intra-Articular Injections for Knee Osteoarthritis: A Systematic Review and Network Meta-analysis.. Arthroscopy, 2024. DOI: 10.1016/j.arthro.2024.01.037.

3. The largest head-to-head trial of cell-based orthobiologics to date randomised 480 patients with KL II-IV knee OA across four arms: autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction, allogeneic umbilical cord tissue-derived MSCs, and a corticosteroid injection control. At 12 months NONE of the three orthobiologic injections was superior to another or to the corticosteroid control on either co-primary endpoint (VAS pain, KOOS pain), and none of the four groups showed a significant change in MRI osteoarthritis score from baseline. No procedure-related serious adverse events were reported.

   Mautner K, et al. — Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial.. Nature Medicine, 2023. DOI: 10.1038/s41591-023-02632-w.

4. The ESSKA-ORBIT European consensus on blood-derived orthobiologics graded 28 question-statement sets; only 9 of 28 had high-level scientific support. Three statements reached grade A: that there is enough preclinical and clinical evidence to support PRP use in knee OA; that clinical evidence shows effectiveness in MILD TO MODERATE knee OA (KL grade 3 or lower); and that PRP provides a longer effect than the short-term effect of corticosteroid with a safer profile. The panel regarded PRP as a valid and possible first-line injectable option for KL grades 1-3.

   Laver L, et al. — The use of injectable orthobiologics for knee osteoarthritis: A European ESSKA-ORBIT consensus. Part 1-Blood-derived products (platelet-rich plasma).. Knee Surgery, Sports Traumatology, Arthroscopy, 2024. DOI: 10.1002/ksa.12077.

5. The 2025 Cochrane review of stem cell injections for knee osteoarthritis pooled 25 randomised trials (1,341 participants) and found that, compared with placebo injection, stem cell injection MAY slightly improve pain (1.2 points better on a 0-10 scale, 7 studies, 445 participants) and function (14.2 points better on a 0-100 scale, 7 studies, 432 participants) up to six months - both rated LOW-certainty evidence, downgraded for indirectness (cell source, preparation and dose varied across studies) and suspected publication bias, since up to three larger RCTs were conducted and withdrawn before reporting results. Radiographic progression was not assessed in any included study.

   Whittle SL, et al. — Stem cell injections for osteoarthritis of the knee.. Cochrane Database of Systematic Reviews, 2025. DOI: 10.1002/14651858.CD013342.pub2.