The main choices differ in speed, cost, and evidence

Cortisone acts fast while gel and PRP take longer

Cortisone reduces swelling and often starts helping within days. If relief keeps fading quickly, discuss other choices before another shot.

Medical gel is a shot of slippery material like the fluid found in joints. Large studies found only a small relief difference from a salt-water shot.

Platelet-rich plasma is shortened to PRP. The clinic spins drawn blood, separates its layers, and saves the platelet-heavy liquid.

At a cut, these blood parts gather and begin the repair response. A needle places the concentrated liquid inside the aching joint or beside its tendon.

Side effects are usually local but warning signs matter

A shot can leave brief soreness, swelling, or bruising where it was given. PRP may cause more early soreness than cortisone or gel.

Call the office that day for fever, spreading redness, drainage, or fast-rising soreness. Don’t stay home for several days with those warning signs.

Tell the provider, the person overseeing care, about blood thinners or bleeding trouble. An active infection also needs to be discussed before any planned shot.

The answer to “does PRP work” changes by joint

In a large knee study, patients and examiners didn’t know who received PRP. After twelve months, PRP and salt-water groups reported about the same relief.

Other knee tests found more relief with PRP than cortisone after several months. The difference wasn’t always large enough for patients to notice.

For elbow soreness, cortisone groups did better before two months. PRP groups reported more relief from six months onward.

Hip-joint and ankle tests found no added relief over salt water. Results from a heel study can’t answer a shoulder question.

Sources

1. A network meta-analysis of 79 randomized trials with 8761 patients compared 11 injectable options for knee osteoarthritis. At 4-6 weeks and 3 months the highest-ranked treatment for WOMAC was high-molecular-weight hyaluronic acid plus corticosteroid; at 6 months the highest-ranked treatment for WOMAC was PRP. Stromal vascular fraction ranked highest for VAS at all time points, on a much thinner evidence base.

   Anil U, Markus DH, Hurley ET, et al. — The efficacy of intra-articular injections in the treatment of knee osteoarthritis: A network meta-analysis of randomized controlled trials. The Knee, 2021. DOI: 10.1016/j.knee.2021.08.008.

2. A systematic review and meta-analysis in the BMJ concluded that strong conclusive evidence indicates viscosupplementation (hyaluronic acid) leads to only a small reduction in knee osteoarthritis pain compared with placebo - less than the minimal clinically important between-group difference - and that based on 15 large placebo-controlled trials in 6462 participants it is associated with a statistically significant higher risk of serious adverse events (relative risk 1.49; 95% CI 1.12-1.98). The findings do not support broad use of viscosupplementation.

   Pereira TV, Juni P, Saadat P, et al. — Viscosupplementation for knee osteoarthritis: systematic review and meta-analysis. BMJ, 2022. DOI: 10.1136/bmj-2022-069722.

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. A Bayesian network meta-analysis of nine studies (six RCTs, 1055 patients) found leukocyte-POOR PRP produced significantly better WOMAC scores than hyaluronic acid (mean difference -21.14; 95% CI -39.63 to -2.65) and than placebo (-17.84; 95% CI -34.95 to -0.73), while leukocyte-RICH PRP showed no such significant difference versus placebo. PRP of either type caused more local adverse reactions than hyaluronic acid (OR 5.63; 95% CI 1.38-22.90), almost always local swelling and pain, with no difference in safety between the two PRP types.

   Riboh JC, Saltzman BM, Yanke AB, et al. — Effect of Leukocyte Concentration on the Efficacy of Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis. American Journal of Sports Medicine, 2016. DOI: 10.1177/0363546515580787.

5. A meta-analysis of 73 articles covering 5,895 patients quantified the PLACEBO response to intra-articular injection in knee osteoarthritis: statistically and clinically significant improvements in pain, function and quality of life at 1, 3 and 6 months, with responder rates above 50% at each of those points, declining by 12 months. The placebo response was stronger in trials with more female participants and in more recently published trials. This is why an uncontrolled 'our patients improved' figure carries almost no information.

   Previtali D, Boffa A, Di Laura Frattura G, et al. — Placebo response to intra-articular injections in knee osteoarthritis: magnitude, evolution over time, and influencing factors. A systematic review and meta-analysis with meta-regression. EFORT Open Reviews, 2025. DOI: 10.1530/EOR-2025-0022.

6. The AAOS third-edition clinical practice guideline for non-arthroplasty management of knee osteoarthritis contains 29 recommendations, and the work group explicitly identified intra-articular corticosteroid, hyaluronic acid AND platelet-rich plasma as areas needing better research - including osteoarthritis characterisation, severity stratification, clinically relevant outcomes with controls for bias, and cost-effectiveness analysis. PRP is presented as an open research question in this guideline, not as a settled treatment.

   Brophy RH, Fillingham YA — AAOS Clinical Practice Guideline Summary: Management of Osteoarthritis of the Knee (Nonarthroplasty), Third Edition. Journal of the American Academy of Orthopaedic Surgeons, 2022. DOI: 10.5435/JAAOS-D-21-01233.

7. A systematic review of 105 clinical PRP studies in orthopaedics published 2006-2016 found that only 11 (10%) described the preparation protocol clearly enough for another investigator to repeat it, and only 17 (16%) reported any quantitative metric of the final PRP composition. The authors concluded that the current reporting of PRP preparation and composition does not allow the PRP products actually delivered to patients to be compared between studies.

   Chahla J, Cinque ME, Piuzzi NS, et al. — A Call for Standardization in Platelet-Rich Plasma Preparation Protocols and Composition Reporting: A Systematic Review of the Clinical Orthopaedic Literature. Journal of Bone and Joint Surgery (American), 2017. DOI: 10.2106/JBJS.16.01374.

8. A meta-analysis of 34 randomized trials (1403 PRP knees, 1426 control knees) found WOMAC favoured PRP over placebo at 12 months (P=.02) and over hyaluronic acid at 6 and 12 months (P<.001), and favoured PRP over steroids on VAS pain and KOOS at 6 months. Critically, the authors reported that the superiority of PRP did NOT reach the minimal clinically important difference for any outcome, and graded the quality of evidence as low.

   Filardo G, Previtali D, Napoli F, et al. — PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials. Cartilage, 2021. DOI: 10.1177/1947603520931170.

9. 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.