What the research says about PRP for each body part

What to know about a worn knee

Research on worn knees gives mixed answers. In one careful study, chance placed people in two groups. One group got PRP. The other got salt water, a comparison shot with no PRP. Both groups reported about the same relief.

Other studies compared PRP with gel or steroid shots. Some found slightly better pain or movement scores with PRP. The gains were sometimes too small for patients to notice.

Research hasn't found that PRP rebuilds cartilage, the slick tissue over each bone end. Thin cartilage can leave the joint stiff and sore. Findings look more hopeful for mild or middle wear than bone-on-bone wear. Still, a study can't promise what you'll feel.

What to ask about hip or back soreness

Hip studies are fewer and less clear. PRP hasn't clearly beaten salt water or gel used as comparison shots. Soreness outside the hip can come from a tendon. A deep groin ache may come from the joint. You can't use the same care for both causes.

Back soreness also has many causes. Small studies looked only at pain thought to come from a worn spinal disc. Some people reported less pain or easier movement. Those studies don't show that PRP helps every sore back.

Ask your doctor to name the likely cause. Then ask whether the study involved the same body part and problem.

When to choose another option

Careful studies found no clear help for an Achilles tendon that stays sore. In an ankle arthritis study, PRP didn't help more than a shot without PRP. That's clearer than a broad claim about all joints.

A sudden pop near your heel can mean a torn tendon. Seek an exam if you can't push off the foot. Waiting for a planned shot could delay the care you need.

The plain question is simple. Did researchers study the painful joint or tendon and the likely cause? If they didn't, ask for evidence that does.

Sources

1. 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.

2. A meta-analysis of eight studies (648 patients, mean age 59) judged at low risk of bias found PRP significantly better than intra-articular corticosteroid for knee OA symptoms at 3, 6 and 9 months (P<0.01), with the largest effects at 6 months (SMD -0.78; 95% CI -1.34 to -0.23) and 9 months (SMD -1.63; 95% CI -2.14 to -1.12). This is the strongest available case for PRP as a longer-acting alternative to a steroid shot.

   McLarnon M, Heron N — Intra-articular platelet-rich plasma injections versus intra-articular corticosteroid injections for symptomatic management of knee osteoarthritis: systematic review and meta-analysis. BMC Musculoskeletal Disorders, 2021. DOI: 10.1186/s12891-021-04308-3.

3. A systematic review and meta-analysis of PRP for hip osteoarthritis found intra-articular PRP more effective at time points earlier than three months, with diverse results between 4 and 12 months and only one included study reporting significantly better outcomes for PRP than the comparator. The authors judged PRP possibly beneficial and safe at mid-term follow-up but said its superiority over alternatives such as hyaluronic acid remains unclear.

   Medina-Porqueres I, Ortega-Castillo M, Muriel-Garcia A — Effectiveness of platelet-rich plasma in the management of hip osteoarthritis: a systematic review and meta-analysis. Clinical Rheumatology, 2021. DOI: 10.1007/s10067-020-05241-x.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.