Could a hyaluronic acid shot help my sore knee?

What is the difference between gel and cortisone?

Cortisone can ease soreness sooner, although its effect may fade. Gel often takes longer, and some people don't feel a useful change.

A salt-water shot has no gel or cortisone in it. It helps show how much relief came from the tested shot itself.

When many knee studies were combined, gel added little relief over salt water. Many people didn't walk easier or hurt less because of the gel.

How are PRP and marrow concentrate different?

PRP means platelet-rich plasma. To make it, the clinic draws your blood and spins it.

Platelets are small blood parts that help clotting and start repair signals. Keeping more platelets makes concentrated PRP, but more alone doesn't prove better relief.

Marrow concentrate instead uses marrow drawn from your pelvis and then spun. Human knee studies haven't clearly shown that marrow brings more relief than PRP.

What should I ask before choosing one?

Human results vary, even when the same type of shot is studied. Some mildly worn knees became less sore and moved more easily for several months.

Other careful studies found little added relief when blood-based care was compared with salt water. That means one good comparison with gel doesn't settle the question.

Ask about cost, expected soreness, follow-up, and days away from usual work. You'll want an answer tied to your joint and amount of wear.

Sources

1. 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.

2. A network meta-analysis restricted to LARGE randomized trials (at least 100 patients per group; 57 RCTs, 22,795 participants, 18 intra-articular interventions) found treatment effects were consistently larger in the 35 high-risk-of-bias trials than in the 22 low/unclear-risk trials. In the main analysis excluding high-risk trials, triamcinolone had the highest probability of exceeding the minimal important difference at weeks 2 and 6; hyaluronic acid had no effect on pain (SMD -0.04, 95% CrI -0.19 to 0.11, 11 trials) but higher odds of dropouts due to adverse events (OR 2.01) and of serious adverse events (OR 1.86). The effects of 16 of the 18 interventions were smaller than the MID and most were consistent with placebo effects.

   Pereira TV, et al. — Effectiveness and safety of intra-articular interventions for knee and hip osteoarthritis based on large randomized trials: A systematic review and network meta-analysis.. Osteoarthritis and Cartilage, 2025. DOI: 10.1016/j.joca.2024.08.014.

3. A meta-analysis of 18 Level I trials (811 PRP vs 797 HA patients, mean follow-up 11.1 months) found mean WOMAC total improvement of 44.7% with PRP versus 12.6% with HA (P<.01). Six of 11 VAS-based studies and 3 of 6 IKDC-based studies favoured PRP significantly. In the subanalysis, leukocyte-POOR PRP was associated with significantly better subjective IKDC scores than leukocyte-rich PRP.

   Belk JW, 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 meta-analysis of 27 Level I studies (1,042 PRP, 226 BMAC, 1,128 HA patients) found significantly better post-injection WOMAC, VAS and subjective IKDC scores for BOTH PRP and BMAC compared with hyaluronic acid - and NO significant difference between PRP and BMAC on any outcome score. This is the clearest published statement that the two most-marketed orthobiologics perform the same as each other in the knee.

   Belk JW, et al. — Patients With Knee Osteoarthritis Who Receive Platelet-Rich Plasma or Bone Marrow Aspirate Concentrate Injections Have Better Outcomes Than Patients Who Receive Hyaluronic Acid: Systematic Review and Meta-analysis.. Arthroscopy, 2023. DOI: 10.1016/j.arthro.2023.03.001.

5. A network meta-analysis of 79 RCTs (8,761 patients) covering eleven injectables - autologous conditioned serum, BMAC, botulinum toxin, corticosteroid, HA, MSC, ozone, saline placebo, PRP, PRGF and stromal vascular fraction - found the top-ranked treatment CHANGES WITH TIME POINT: high-molecular-weight HA plus corticosteroid ranked first for WOMAC at 4-6 weeks and 3 months, while PRP ranked first at 6 months. This is the clearest demonstration that 'which injection is best' depends entirely on when you measure.

   Anil U, 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.

6. A network meta-analysis of 64 trials (9,710 patients) that deliberately separated WITHIN-CLASS variants found high-molecular-weight hyaluronic acid was the only treatment whose confidence interval lay entirely above the minimal important difference for BOTH pain and function. PRP's pain estimate also cleared the MID but varied across sensitivity analyses, leaving its efficacy uncertain; extended-release corticosteroid showed possible benefit over standard-release corticosteroid.

   Phillips M, et al. — Differentiating factors of intra-articular injectables have a meaningful impact on knee osteoarthritis outcomes: a network meta-analysis.. Knee Surgery, Sports Traumatology, Arthroscopy, 2020. DOI: 10.1007/s00167-019-05763-1.

7. The BMJ meta-analysis of viscosupplementation pooled 169 trials (21,163 participants) and found clear evidence of small-study effects and publication bias. In the prespecified main analysis of 24 LARGE placebo-controlled trials (8,997 participants) hyaluronic acid reduced pain by SMD -0.08 (95% CI -0.15 to -0.02), equivalent to 2.0 mm on a 100 mm scale - far below the -0.37 minimal important difference - and trial sequential analysis showed there has been CONCLUSIVE evidence of clinical equivalence to placebo since 2009. Fifteen large trials showed a significantly higher risk of serious adverse events (RR 1.49).

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

8. The 2012 Annals of Internal Medicine meta-analysis of 89 viscosupplementation trials (12,667 adults) is the classic demonstration of publication bias in this field: the pooled effect across 71 trials was -0.37, but five UNPUBLISHED trials showed an effect size of -0.03, and 18 large trials with blinded outcome assessment showed a clinically irrelevant -0.11. Fourteen trials showed an increased risk of serious adverse events (RR 1.41).

   Rutjes AW, et al. — Viscosupplementation for osteoarthritis of the knee: a systematic review and meta-analysis.. Annals of Internal Medicine, 2012. DOI: 10.7326/0003-4819-157-3-201208070-00473.

9. The 2015 Annals network meta-analysis of 137 studies (33,243 participants) compared oral and injected drugs for knee OA and found ALL interventions significantly outperformed oral placebo for pain, with intra-articular hyaluronic acid the most efficacious (effect size 0.63) and acetaminophen the least (0.18). Intra-articular treatments outperformed NSAIDs, which the authors noted may partly reflect the integrated effect of the injection process itself.

   Bannuru RR, et al. — Comparative effectiveness of pharmacologic interventions for knee osteoarthritis: a systematic review and network meta-analysis.. Annals of Internal Medicine, 2015. DOI: 10.7326/M14-1231.

10. A randomized trial allocated 175 patients with KL II-IV knee OA to BMAC (n=111), PRP (n=34) or hyaluronic acid (n=30) and followed them for 12 months. All three produced significant improvement from baseline in WOMAC, KOOS and IKDC with no serious side effects; BMAC showed significantly better clinical improvement than PRP and HA on most scores, and PRP scored higher than HA without reaching statistical significance. Note the unequal, non-blinded design - this is the strongest direct BMAC-versus-PRP randomized comparison available, and it is not a strong design.

    Dulic O, et al. — Bone Marrow Aspirate Concentrate versus Platelet Rich Plasma or Hyaluronic Acid for the Treatment of Knee Osteoarthritis.. Medicina (Kaunas), 2021. DOI: 10.3390/medicina57111193.

11. A 2026 network meta-analysis of 21 RCTs (2,254 patients) found both leukocyte-rich and leukocyte-poor PRP significantly superior to placebo and to hyaluronic acid for function at 6-12 months (MD vs placebo -13.20 and -10.54 respectively). LP-PRP ranked highest (P-score 0.96) but the DIRECT comparison between the two formulations showed no statistically significant difference, and the authors concluded there is insufficient evidence to recommend one PRP formulation over the other.

    Xu B, et al. — Leukocyte-rich versus leukocyte-poor platelet-rich plasma and hyaluronic acid for knee osteoarthritis: a systematic review and network meta-analysis.. Journal of Orthopaedic Surgery and Research, 2026. DOI: 10.1186/s13018-026-06689-4.

12. A meta-analysis of the PLACEBO arms of 73 double-blind trials (5,895 patients) quantified what a saline knee injection alone achieves: statistically and clinically significant improvement in pain, function and quality of life at 1, 3 and 6 months, with responder rates exceeding 50% at all three time points, peaking around 4-8 months and declining by 12 months. Placebo response was stronger in trials with more female participants and in more recently published trials.

    Previtali D, 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.

13. FDA states verbatim of stem cell products, stromal vascular fraction (adipose-derived cells), umbilical cord blood, Wharton's jelly, amniotic fluid and exosome products: 'None of these products have been approved for the treatment of any orthopedic condition, such as osteoarthritis, tendonitis, disc disease, tennis elbow, back pain, hip pain, knee pain, neck pain, or shoulder pain.' The only FDA-approved stem cell products in the United States are blood-forming (hematopoietic progenitor) cells derived from umbilical cord blood, approved only for disorders of blood production, and there are currently NO FDA-approved exosome products.

    U.S. Food and Drug Administration — Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes. FDA (Center for Biologics Evaluation and Research), 2020.