Complications of Platelet-Rich Plasma Injection for Knee Osteoarthritis Are Similar to Those of Corticosteroids and Hyaluronic Acid but Are Significantly Greater Than Those of Placebo Injections: A Meta-analysis of Randomized Controlled Trials

Arthroscopy. 2025 Nov;41(11):4789-4803. doi: 10.1016/j.arthro.2025.05.018. Epub 2025 May 21.

Abstract

Purpose: To investigate complications of platelet-rich plasma (PRP) injections for knee osteoarthritis (OA) compared with other injected substances including hyaluronic acid (HA), corticosteroids, and placebo saline solution.

Methods: The PubMed, Embase, Web of Science, and Cochrane databases were searched to identify randomized controlled trials (RCTs) comparing PRP with another injectable treatment for knee OA with documented complications. Studies not mentioning complications or using PRP during surgery were excluded. Complications were pooled to determine the overall complication rate and the number needed to harm (NNH). Subgroup analyses were performed for studies comparing PRP with HA, corticosteroids, and placebo saline solution using DerSimonian-Laird random-effects models displaying odds ratios (ORs).

Results: Twenty-four RCTs were identified, with 2,751 total patients, 1,318 of whom received PRP injections. A total of 246 complications occurred in the PRP group versus 131 in the comparison cohort (18.66% vs 9.14%, P < .01). The NNH was 11. Subgroup analysis showed no difference in the odds of complications when PRP was compared with HA (OR = 1.33, P = .22, I2 = 0.0%) and corticosteroids (OR = 3.07, P = .35, I2 = 63.49%) but showed significantly more complications when compared with placebo (OR = 4.88, P < .01, I2 = 0.00%). Only 1 patient reported severe pain; all other complications were described as moderate or mild and self-limiting.

Conclusions: The use of PRP for knee OA is not innocuous, with a significantly higher rate of complications compared with placebo. However, most complications were reported as mild to moderate, and the odds of complications are similar to those of HA or corticosteroid injections. Compared with all other injectables, the NNH for PRP is 11, which is important for physicians to consider prior to PRP therapy.

Level of evidence: Level II, meta-analysis of Level I and II randomized control trials.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Adrenal Cortex Hormones* / administration & dosage
  • Adrenal Cortex Hormones* / adverse effects
  • Humans
  • Hyaluronic Acid* / administration & dosage
  • Hyaluronic Acid* / adverse effects
  • Injections, Intra-Articular
  • Osteoarthritis, Knee* / therapy
  • Platelet-Rich Plasma*
  • Randomized Controlled Trials as Topic
  • Viscosupplements / administration & dosage
  • Viscosupplements / adverse effects

Substances

  • Hyaluronic Acid
  • Adrenal Cortex Hormones
  • Viscosupplements