Table 2.
Summary of the efficacy of intra-articular PRP injections in knee OA.
| Authors | Year | Type of Study | Main Findings |
|---|---|---|---|
| Tucker et al. [37] | 2021 | Single-blinded, randomized, placebo-controlled pilot study | The PRP treatment group had less pain and stiffness and improved function scores than the placebo (saline) group |
| Yurtbay et al. [38] | 2021 | Randomized, double-blind, placebo-controlled clinical trial | Compared with placebo (sodium saline), LR-PRP treatment was effective in the treatment of OA. Multiple doses of PRP increased the treatment efficacy and duration. Patients aged 51–65 years scored better at 6 months |
| Bennell et al. [39] | 2021 | Randomized, 2-group, placebo-controlled, participant-, injector-, and assessor-blinded clinical trial | Among patients with symptomatic mild-to-moderate radiographic knee OA, intra-articular PRP injection, compared with injection of saline placebo, did not result in a significant difference in symptoms or joint structure at 12 months. |
| Dório et al. [40] | 2021 | Randomized, double-blind, placebo-controlled trial of 3 groups of patients: PRP, plasma, and saline. | There were no differences among the 3 study groups at weeks 6 and 12. |
| Kim et al. [41] | 2021 | Systematic review and meta-analysis (level of evidence IV) | Intra-articular PRP injection resulted in improvements above the minimal clinically important difference in terms of pain and function up to 12 months. |
| Nie et al. [42] | 2021 | Meta-analysis of randomized controlled clinical trials (level of evidence I) | PRP injections were beneficial for pain alleviation and functional improvement in knee OA. |
| Li et al. [43] | 2021 | Literature review | Compared with many other treatment methods, intra-articular injection of PRP proved to be safe and effective to improve the quality of life of patients with knee OA. |
| Hong et al. [44] | 2021 | Systematic review and meta-analysis | Compared with placebo, PRP had a lower VAS score and higher IKDC subjective score at 6 months after treatment and a significantly lower WOMAC score during the follow-up period. |
| Aiyer et al. [45] | 2021 | Systematic review of clinical studies | These authors recommended PRP for patients with early-stage OA (I or II) and who are aged younger than 65. |
| Moton et al. [46] | 2021 | Prospective case series | PRP injections for treating OA (grade 1 to 3) proved to be successful in terms of improving functional outcomes and reducing pain intensity. |
| Sun et al. [47] | 2021 | Case series | One injection of PRP improved pain and function for 6 months for patients with early knee OA. |
| Bec et al. [48] | 2021 | Case series (retrospective study) | A single injection of pure PRP resulted in significant clinical improvement in the management of knee OA. |
| Hegaze et al. [49] | 2021 | Prospective case series | Intra-articular injections gave significant pain and flexion improvement in patients with grades II, III, and IV OA, especially with multiple injections in the short-term follow-up. |
| Rai et al. [50] | 2021 | Case series | PRP was a safe and effective therapy for early OA knees. It provided a significant clinical improvement in patients, with some loss of improvement with time. |
| Jayaram et al. [51] | 2021 | Case series | LR-PRP demonstrated efficacy in meaningful end points for functional and patient-reported outcomes at early time points in patients with knee OA. |
PRP = platelet-rich plasma; LR-PRP = leukocyte rich PRP; OA = osteoarthritis; VAS = visual analog scale; IKDC = International Knee Documentation Committee; WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index.