Standardization of Platelet-Rich Plasma Preparation in Orthopedics: A Review of the Literature and Proposal for a Reproducible Protocol

Platelet-rich plasma (PRP) is widely used in orthopedics and sports medicine as an autologous product; however, substantial heterogeneity in manufacture and incomplete reporting of preparation parameters limits reproducibility and inter-study comparability.: We performed a PRISMA-guided methodological review of studies describing PRP preparation, subsequently focusing on orthopedic applications. MEDLINE/PubMed, Embase, Scopus, the Cochrane Library, Web of Science, and Google Scholar were searched. 7330 records were retrieved; following merging and de-duplication, more than 2500 unique records were screened. The inclusion criteria for our study required studies on PRP that focused on orthopedic use of this preparation and studies that reported a defined methodology for PRP, reported in the abstract or in the manuscript. Extracted variables covered collection and anticoagulation, centrifugation strategy, cellular composition, activation/lysis, processing environment, storage, and time-to-use. Twenty-three orthopedic studies met the inclusion criteria. Whole blood draw volume and anticoagulant were reported in 15/23 studies each; centrifugation parameters (relative centrifugal force/RPM and duration) in 12/23; and PRP phenotype (e.g., leukocyte-poor vs. leukocyte-rich) in 15/23. Platelet metrics (baseline and/or final platelet count/concentration) were reported in 6/23. Sterility/environmental controls were mentioned in 17/23, whereas storage conditions and time-to-use were described in only 3/23. An explicit exogenous activation agent was reported on 1/23. Orthopedic PRP studies frequently omit critical manufacturing and handling descriptors—particularly platelet dose, leukocyte/lymphocyte handling, temperature control, storage/freezing conditions, and time-to-administration—impairing reproducibility and dose comparability. We propose a pragmatic, standardized protocol for preparation of leucocyte/lymphocyte-depleted PRP for orthopedic use (PRP only, without gelification), together with a minimum set of data and parameters to be evaluated. In our opinion these parameters should be included in future studies in order to standardize the production process. The quality of PRP itself could be impacted by such standardization, and the ability to objectively evaluate the results of studies could be enhanced by facilitating the comparison of data emerging from the literature.