Corresponding Author: Liam D. A. Paget, MD, Amsterdam UMC, University of Amsterdam, Department of Orthopedic Surgery, Amsterdam Movement Sciences, PO Box 22660, 1100 DD Amsterdam, the Netherlands (L.d.paget@amsterdamumc.nl).
Accepted for Publication: September 10, 2021.
Author Contributions: Dr Paget had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: All authors.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Paget, Reurink, Tol.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Paget, Reurink, de Vos, Weir, Bierma-Zeinstra, Tol.
Obtained funding: de Vos, Moen, Kerkhoffs, Tol.
Administrative, technical, or material support: Paget, Reurink, Weir, Moen, Stufkens, Kerkhoffs, Tol.
Supervision: Reurink, Tol.
Conflict of Interest Disclosures: Dr Paget reported receiving an institutional grant from the Dutch Arthritis Society and institutional nonfinancial support from Arthrex (Hettich centrifuge on loan) during the conduct of the study. Dr Reurink reported receiving an institutional grant from the Dutch Arthritis Society and institutional nonfinancial support from Arthrex (Hettich centrifuge on loan) during the conduct of the study. Dr de Vos reported receiving institutional nonfinancial support from Arthrex (Hettich centrifugation system on loan) during the conduct of the study. Dr Weir reported receiving institutional nonfinancial support from Arthrex (Hettich centrifugation system) on loan during the conduct of the study. Dr Moen reported receiving institutional nonfinancial support from Arthrex (Hettich centrifuge on loan) during the conduct of the study. Dr Bierma-Zeinstra reported receiving or having independent research grants pending from The Netherlands Organisation for Health Research and Development, CZ, European Union, Foreum, the Dutch Arthritis Society, personal fees from Osteoarthritis Research Society International as an associate editor of Osteoarthritis and Cartilage, and consultancy fees from Pfizer outside the submitted work. Dr Stufkens reported receiving an institutional grant from the Dutch Arthritis Society and institutional nonfinancial support from Arthrex (Hettich centrifuge on loan) during the conduct of the study. Dr Kerkhoffs reported receiving an institutional grant from the Dutch Arthritis Society and nonfinancial support from Arthrex (Hettich centrifuge on loan) during the conduct of the study and grants from Arthrex for research-related payments and personal fees as an associate editor for the Knee Surgery, Sports Traumatology, Arthroscopy outside the submitted work. Dr Tol reported grants from the Dutch Arthritis Society (a Dutch nonprofit patient organization) and institutional nonfinancial support from Arthrex (Hettich centrifuge on loan) during the conduct of the study.
Funding/Support: This study was supported by a grant from the Dutch Arthritis Society.
Role of the Funder/Sponsor: The funder of the study (The Dutch Arthritis Society [nonprofit patient organization]) had no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. The platelet-rich plasma centrifugation system was on loan from Arthrex (Arthrex Medizinische Instrumente GmbH), as is customary under usual care.
Group Information: PRIMA Study Group members are shown in Supplement 3.
Data Sharing Statement: See Supplement 4.
Additional Contributions: In addition to the named authors, the PRIMA study group included Simon Goedegebuure, MD (primary investigator [PI]; The Sport Physician Group, Department of Sports Medicine, OLVG); Rover Krips, PhD (PI; Department of Orthopaedic Surgery, Flevoziekenhuis); Mario Maas, PhD (Amsterdam UMC, University of Amsterdam, Department of Radiology and Nuclear Medicine, Division of Musculoskeletal Radiology); Duncan E. Meuffels, PhD (Department of Orthopaedic Surgery and Sports Medicine, Erasmus University Medical Center); and Peter A. Nolte, PhD (PI; Department of Orthopaedic Surgery, Spaarne Gasthuis). We thank the Dutch Arthritis Society, a nonprofit patient organization, for funding this study. None of the following contributors received compensation for their role in the study. We appreciate the time, effort, and precision that the independent statistical expert Jos Runhaar, PhD (Erasmus MC University Medical Center, Rotterdam, the Netherlands), and independent investigator Teppo Järvinen, PhD (University of Helsinki, Helsinki University Central Hospital, Finland), dedicated to this study. We also thank the research assistants and administrative staff at all locations for their diligence and flexibility: J. Nienke Altink (Amsterdam UMC, the Netherlands), Myrthe T. Beekhuis-Heerema, MD (OLVG, Amsterdam, the Netherlands); Rosemary van den Berg (OLVG, Amsterdam, the Netherlands); Robin P. Blom, MD (Flevoziekenhuis, Almere, the Netherlands); Tristan M. F. Buck (Amsterdam UMC, the Netherlands); Jari Dahmen, MD (Amsterdam UMC, the Netherlands); Quinten Dusoswa, MD (Flevoziekenhuis, Almere, the Netherlands); Kaj S. Emanuel, PhD (Amsterdam UMC, the Netherlands); Eline M. van Es, MSc (Erasmus MC University Medical Center, Rotterdam, the Netherlands); Mienie Hermans (Flevoziekenhuis, Almere, the Netherlands); Alexander Hoorntje, MD (Flevoziekenhuis, Almere, the Netherlands); Ozgur Kilic, MD (Amsterdam UMC, the Netherlands); Anne D. van der Made, MD (Amsterdam UMC, the Netherlands); Marjo van der Poel (Spaarne Gasthuis, Hoofddorp, the Netherlands); Christine M. E. Rustenburger, PhD (Amsterdam UMC, the Netherlands); Marjolein Schager, M.Th. (Spaarne Gasthuis, Hoofddorp, the Netherlands); T. Stornebrink, MD (Amsterdam UMC, the Netherlands); Joep J. M. Suskens, MSc (Amsterdam UMC, the Netherlands); Lukas P. E. Verweij (Amsterdam UMC, the Netherlands); Gwendolyn Vuurberg, PhD (Amsterdam UMC, the Netherlands); Tom G. H.Wiggers, MD (OLVG, Amsterdam, the Netherlands); Annika Willems, MSc (Erasmus MC University Medical Center, Rotterdam, the Netherlands); and Tugba Ulucay (Amsterdam UMC, the Netherlands).