Knees, heels and elbows have different PRP evidence by condition

Knee results conflict, while hip and ankle results are weaker

Knee arthritis has more research than the other joints, but the results disagree. One study compared PRP with saline, which is germ-free salt water given as the comparison treatment.

After twelve months, knees given PRP didn’t hurt less than knees given salt water. In other studies, PRP did better than a hyaluronic acid joint gel.

Hip studies haven’t shown PRP to work better than that same gel. An ankle study compared PRP with salt water and found no useful drop in soreness.

Elbow and heel studies report later relief, but the rear ankle does not

In one tennis elbow study, PRP didn’t improve soreness more at twelve weeks. By twenty-four weeks, the PRP group reported a meaningful gain in elbow comfort and use.

Reports on plantar fasciitis, soreness from the thick band under the heel, favor PRP after several months. Studies of the Achilles tendon, the strong cord behind the ankle, haven’t shown added relief.

Shoulder results also disagree across different injuries and types of care. An elbow result can’t tell you whether a shoulder treatment will help.

The exam shows which body-part study applies

A visit starts with where it hurts, when it began and the action that worsens it. The clinician may check motion and strength, then review an X-ray already taken.

Until then, move gently and stop the chore that brings sharp pain. Note swelling, lost sleep and soreness the next morning.

Tell the clinic which task you most want to regain, such as walking or dressing. Then ask how often the study showed that result and when it appeared.

A small change that doesn’t improve that task may not justify the cost. The body part, comparison and timing should all match the choice being discussed.

Sources

1. A clinical-recommendations review graded PRP indication by indication: good evidence for leukocyte-poor PRP in knee osteoarthritis; moderate-to-high-quality evidence for leukocyte-rich PRP in patellar tendinopathy and for PRP in plantar fasciitis; INSUFFICIENT evidence to routinely recommend PRP for rotator cuff tendinopathy, hip osteoarthritis or high ankle sprains; and demonstrated LACK of efficacy for Achilles tendinopathy, muscle injuries, acute fracture or non-union, and as a surgical augment in rotator cuff repair, Achilles repair and ACL reconstruction.

   Le ADK, Enweze L, DeBaun MR, et al. — Current Clinical Recommendations for Use of Platelet-Rich Plasma. Current Reviews in Musculoskeletal Medicine, 2018. DOI: 10.1007/s12178-018-9527-7.

2. In the RESTORE trial - the largest placebo-controlled PRP trial in knee osteoarthritis - 288 adults aged 50+ with symptomatic Kellgren-Lawrence grade 2-3 medial knee OA received three weekly intra-articular injections of leukocyte-poor PRP from a commercial system or saline placebo. At 12 months the mean change in knee pain was -2.1 points with PRP versus -1.8 with saline (difference -0.4; 95% CI -0.9 to 0.2; P=.17) against a minimum clinically important difference of 1.8, and the change in medial tibial cartilage volume was -1.4% versus -1.2% (difference -0.2%; 95% CI -1.9% to 1.5%; P=.81). Twenty-nine of 31 prespecified secondary outcomes showed no significant between-group difference. The authors concluded the findings do not support use of PRP for knee OA.

   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. DOI: 10.1001/jama.2021.19415.

3. A meta-analysis of 18 Level I randomized trials (811 patients receiving PRP, 797 receiving hyaluronic acid, mean follow-up 11.1 months) found mean improvement in total WOMAC scores was significantly higher with PRP (44.7%) than with hyaluronic acid (12.6%) (P<.01), and 6 of 11 VAS-reporting studies found significantly less pain with PRP at latest follow-up.

   Belk JW, Kraeutler MJ, Houck DA, et al. — Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials. American Journal of Sports Medicine, 2021. DOI: 10.1177/0363546520909397.

4. In a double-blind, placebo-controlled trial of 54 patients with chronic midportion Achilles tendinopathy, all doing eccentric exercises, VISA-A scores improved 21.7 points with PRP and 20.5 points with saline over 24 weeks - an adjusted between-group difference of -0.9 (95% CI -12.4 to 10.6), excluding the predefined relevant difference of 12 points. PRP added nothing to eccentric loading.

   de Vos RJ, Weir A, van Schie HT, et al. — Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial. JAMA, 2010. DOI: 10.1001/jama.2009.1986.

5. A 24-site, 240-patient participant-blinded randomized trial of a single intratendinous PRP injection versus a sham (subcutaneous dry needle) for chronic midportion Achilles tendinopathy found VISA-A scores of 54.4 versus 53.4 at six months (adjusted mean difference -2.7; 95% CI -8.8 to 3.3) against a 12-point minimal clinically important difference. The authors stated the findings do not support the use of this treatment for chronic midportion Achilles tendinopathy.

   Kearney RS, Ji C, Warwick J, et al. — Effect of Platelet-Rich Plasma Injection vs Sham Injection on Tendon Dysfunction in Patients With Chronic Midportion Achilles Tendinopathy: A Randomized Clinical Trial. JAMA, 2021. DOI: 10.1001/jama.2021.6986.

6. An updated meta-analysis of six randomized trials (422 patients) found no benefit of PRP over placebo for Achilles tendinopathy on VISA-A at 3 months (mean difference 1.7; 95% CI -1.8 to 5.2), 6 months (0.5; 95% CI -8.5 to 9.3) or 1 year (-7.9; 95% CI -27.3 to 11.6), nor on VAS pain at 3 months. Funnel-plot asymmetry suggested publication bias inflating apparent benefits. The authors wrote that PRP should not be used to treat Achilles tendinopathy until high-quality trials show a clear clinical benefit.

   Barreto ESR, Antunes Junior CR, Silva IC, et al. — Is Platelet-rich Plasma Effective in Treating Achilles Tendinopathy? A Meta-analysis of Randomized Clinical Trials. Clinical Orthopaedics and Related Research, 2025. DOI: 10.1097/CORR.0000000000003349.

7. A 12-centre randomized controlled trial of 230 patients with chronic lateral epicondylar tendinopathy compared tendon needling with leukocyte-enriched PRP against tendon needling alone. At 12 weeks there was no significant difference (55.1% versus 47.4% pain improvement; P=.163). At 24 weeks the PRP group reported 71.5% versus 56.1% pain improvement (P=.019), a 83.9% versus 68.3% success rate (P=.037), and significantly less residual elbow tenderness (29.1% versus 54.0%; P=.009). No significant complications occurred in either group.

   Mishra AK, Skrepnik NV, Edwards SG, et al. — Efficacy of platelet-rich plasma for chronic tennis elbow: a double-blind, prospective, multicenter, randomized controlled trial of 230 patients. American Journal of Sports Medicine, 2014. DOI: 10.1177/0363546513494359.

8. A systematic review and meta-analysis of nine randomized trials (239 PRP patients, 240 corticosteroid patients) in chronic plantar fasciitis found statistically significant differences in VAS pain favouring PRP at 1-1.5, 3, 6 and 12 months, and in AOFAS function favouring PRP at 6 and 12 months (no difference at 1 and 3 months).

   Hurley ET, Shimozono Y, Hannon CP, et al. — Platelet-Rich Plasma Versus Corticosteroids for Plantar Fasciitis: A Systematic Review of Randomized Controlled Trials. Orthopaedic Journal of Sports Medicine, 2020. DOI: 10.1177/2325967120915704.

9. A multicentre, double-blinded, placebo-controlled trial randomised 100 patients with ankle (tibiotalar) osteoarthritis to two ultrasound-guided intra-articular injections of PRP or placebo. Symptom scores improved by 10 points with PRP and 11 points with placebo, an adjusted between-group difference over 26 weeks of -1 (95% CI -6 to 3; P=.56). The authors concluded the results do not support the use of PRP injections for ankle osteoarthritis.

   Paget LDA, Reurink G, de Vos RJ, et al. — Effect of Platelet-Rich Plasma Injections vs Placebo on Ankle Symptoms and Function in Patients With Ankle Osteoarthritis: A Randomized Clinical Trial. JAMA, 2021. DOI: 10.1001/jama.2021.16602.

10. A meta-analysis of six randomized trials (211 PRP patients, 197 hyaluronic acid patients, mean follow-up about 12 months) in hip osteoarthritis found NO significant difference between PRP and hyaluronic acid in weighted improvement on WOMAC, VAS or Harris Hip Score - including in a subanalysis isolating leukocyte-poor PRP.

    Belk JW, Houck DA, Littlefield CP, et al. — Platelet-Rich Plasma Versus Hyaluronic Acid for Hip Osteoarthritis Yields Similarly Beneficial Short-Term Clinical Outcomes: A Systematic Review and Meta-analysis of Level I and II Randomized Controlled Trials. Arthroscopy, 2022. DOI: 10.1016/j.arthro.2021.11.005.

11. A prospective, double-blind randomized controlled study of intradiscal PRP for chronic (6 months or more) lumbar discogenic pain unresponsive to conservative treatment found participants receiving PRP had significant improvements in Functional Rating Index, NRS best pain and NASS satisfaction at 8 weeks compared with controls, with FRI improvement maintained through at least one year. No disc-space infection, neurologic injury or progressive herniation was reported. The authors called for further work to define which patients respond and what the ideal injectate is.

    Tuakli-Wosornu YA, Terry A, Boachie-Adjei K, et al. — Lumbar Intradiskal Platelet-Rich Plasma (PRP) Injections: A Prospective, Double-Blind, Randomized Controlled Study. PM&R, 2016. DOI: 10.1016/j.pmrj.2015.08.010.

12. The Cochrane review of platelet-rich therapies for musculoskeletal soft-tissue injuries concluded there is currently insufficient evidence to support the use of platelet-rich therapy for treating musculoskeletal soft tissue injuries, overall and for individual conditions - including pooled data from six trials of PRP applied during rotator cuff repair surgery, which showed no statistically or clinically significant long-term functional difference. The review ended with an explicit call for standardisation of PRP preparation methods.

    Moraes VY, Lenza M, Tamaoki MJ, et al. — Platelet-rich therapies for musculoskeletal soft tissue injuries. Cochrane Database of Systematic Reviews, 2014. DOI: 10.1002/14651858.CD010071.pub3.

13. The devices used to spin PRP at the point of care are cleared by FDA as clinical centrifuges, product code JQC, a Class I device under 21 CFR 862.2050 - for example the Biomet GPS Platelet Separation Kit (K030555, cleared 2003) and the Harvest SmartPrep2 / SmartPrep Platelet Concentration System (K103340, cleared 2010). That clearance covers the equipment that separates blood. It is not an FDA approval of platelet-rich plasma as a treatment for osteoarthritis, tendinopathy or any other orthopedic condition, and copy must never blur the two.

    U.S. Food and Drug Administration (Center for Devices and Radiological Health) — 510(k) Premarket Notification database and Product Classification: JQC, Centrifuges (Micro, Ultra, Refrigerated) For Clinical Use, 21 CFR 862.2050. FDA accessdata (CDRH device databases), 2003.