A systematic review on the high variability in study design and outcome reporting in randomized controlled trials examining intra-articular platelet-rich plasma injection for knee osteoarthritis

Abstract

Background: Prior literature has demonstrated variability in the preparation of platelet-rich plasma (PRP) for knee osteoarthritis, but it is unclear if study design and postoperative outcomes have been standardized for this intervention. Objective: To determine the variability in study design and outcome reporting across randomized controlled trials (RCTs) examining intra-articular PRP injections for knee osteoarthritis. Data source: The Cochrane Database, PubMed, EMBASE, and MEDLINE. Study eligibility criteria, participants, and interventions: Level I and II RCTs examining intra-articular PRP injections for knee osteoarthritis were included. Study appraisal and synthesis methods: The Jadad score was utilized. Results: Twenty-seven studies were included. Five studies conducted repeat imaging postoperatively. Visual Analog Scale (VAS) Pain (63%) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (59.3%) were the 2 most utilized PROMs, followed by Knee Injury and Osteoarthritis Outcome Score (KOOS) (29.6%). Twelve (44%) RCTs reported 3 or more PROM (ie, VAS, KOOS, WOMAC). Most RCTs did not report objective outcome measures (70.4%). Limitations: The findings were largely descriptive in nature with limited utilization of statistical evaluation. Conclusions and implications of key findings: RCTs examining outcomes after intra-articular PRP injection for knee OA demonstrate substantial variability. Standardizing the population of most benefit with respect to arthritis grade may help in limiting population heterogeneity for future study comparison and pooling. In addition, PROs should be reported in a domain-specific manner allowing for assessment of pain, function, and health-related quality of life. Systematic review registry number: This review was not registered with PROSPERO. Level of Evidence: II; Systematic Review of Level I-II RCTs.

Keywords

• PRP
• Platelet rich plasma
• Osteoarthritis
• RCT
• Kellgren-Lawrence