Efficacy of Intra-articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Systematic Review

Published:September 29, 2015DOI:


      To determine (1) whether platelet-rich plasma (PRP) injection significantly improves validated patient-reported outcomes in patients with symptomatic knee osteoarthritis (OA) at 6 and 12 months postinjection, (2) differences in outcomes between PRP and corticosteroid injections or viscosupplementation or placebo injections at 6 and 12 months postinjection, and (3) similarities and differences in outcomes based on the PRP formulations used in the analyzed studies.


      PubMed, Cochrane Central Register of Controlled Trials, SCOPUS, and Sport Discus were searched for English-language, level I evidence, human in vivo studies on the treatment of symptomatic knee OA with intra-articular PRP compared with other options, with a minimum of 6 months of follow-up. A quality assessment of all articles was performed using the Modified Coleman Methodology Score (average, 83.3/100), and outcomes were analyzed using 2-proportion z-tests.


      Six articles (739 patients, 817 knees, 39% males, mean age of 59.9 years, with 38 weeks average follow-up) were analyzed. All studies met minimal clinical important difference criteria and showed significant improvements in statistical and clinical outcomes, including pain, physical function, and stiffness, with PRP. All but one study showed significant differences in clinical outcomes between PRP and hyaluronic acid (HA) or PRP and placebo in pain and function. Average pretreatment Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were 52.36 and 52.05 for the PRP and HA groups, respectively (P = .420). Mean post-treatment WOMAC scores for PRP were significantly better than for HA at 3 to 6 months (28.5 and 43.4, respectively; P = .0008) and at 6 to 12 months (22.8 and 38.1, respectively; P = .0062). None of the included studies used corticosteroids.


      In patients with symptomatic knee OA, PRP injection results in significant clinical improvements up to 12 months postinjection. Clinical outcomes and WOMAC scores are significantly better after PRP versus HA at 3 to 12 months postinjection. There is limited evidence for comparing leukocyte-rich versus leukocyte-poor PRP or PRP versus steroids in this study.

      Level of Evidence

      Level I, systematic review of Level I studies.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Arthroscopy
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Curl W.W.
        • Krome J.
        • Gordon E.S.
        • Rushing J.
        • Smith B.P.
        • Poehling G.G.
        Cartilage injuries: a review of 31516 knee arthroscopies.
        Arthroscopy. 1997; 13: 456-460
        • Riddle D.L.
        • Jiranek W.A.
        • Hayes C.W.
        Use of a validated algorithm to judge the appropriateness of total knee arthroplasty in the United States: a multicenter longitudinal cohort study.
        Arthritis Rheumatol. 2014; 66: 2134-2143
        • Brown G.A.
        AAOS clinical practice guidelines. Treatment of osteoarthritis of the knee: evidence-based guideline, 2d ed.
        J Am Acad Orthop Surg. 2013; 21: 577-579
        • Kabiri A.
        • Esfandiari E.
        • Esmaeili A.
        • Hashemibeni B.
        • Pourazar A.
        • Mardani M.
        Platelet-rich plasma application in chondrogenesis.
        Adv Biomed Res. 2014; 3: 138
        • Sundman E.A.
        • Cole B.J.
        • Karas V.
        • et al.
        The anti-inflammatory and matrix restorative mechanisms of platelet-rich plasma in osteoarthritis.
        Am J Sports Med. 2014; 42: 35-40
        • Sadoghi P.
        • Rosso C.
        • Valderrabano V.
        • Leithner A.
        • Vavken P.
        The role of platelets in the treatment of Achilles tendon injuries.
        J Orthop Res. 2013; 31: 111-118
        • Malavolta E.A.
        • Gracitelli M.E.
        • Ferreira Neto A.A.
        • Assunção J.H.
        • Bordalo-Rodrigues M.
        • de Camargo O.P.
        Platelet-rich plasma in rotator cuff repair: a prospective randomized study.
        Am J Sports Med. 2014; 42: 2446-2454
        • Dragoo J.L.
        • Wasterlain A.S.
        • Braun H.J.
        • Nead K.T.
        Platelet-rich plasma as a treatment for patellar tendinopathy. A double-blind, randomized controlled trial.
        Am J Sports Med. 2014; 42: 610-618
        • A Hamid M.S.
        • Mohamed Ali M.R.
        • Yusof A.
        • George J.
        • Lee L.P.
        Platelet-rich plasma injections for the treatment of hamstring injuries: a randomized controlled trial.
        Am J Sports Med. 2014; 42: 2410-2418
        • Kim HJ1
        • Yeom J.S.
        • Koh Y.G.
        • et al.
        Anti-inflammatory effect of platelet-rich plasma on nucleus pulposus cells with response of TNF-α and IL-1.
        J Orthop Res. 2014; 32: 551-556
        • van Buul G.M.
        • Koevoet W.L.
        • Kops N.
        • et al.
        Platelet-rich plasma releasate inhibits inflammatory processes in osteoarthritic chondrocytes.
        Am J Sports Med. 2011; 39: 2362-2370
        • Bendinelli P.
        • Matteucci E.
        • Dogliotti G.
        • et al.
        Molecular basis of anti-inflammatory action of platelet-rich plasma on human chondrocytes: mechanisms of NF-kappa B inhibition via HGF.
        J Cell Physiol. 2010; 225: 757-766
        • Nguyen R.T.
        • Borg-Stein J.
        • McInnis K.
        Applications of platelet-rich plasma in musculoskeletal and sports medicine: an evidence-based approach.
        PM&R. 2011; 3: 226-250
        • Sheth U.
        • Simunovic N.
        • Klein G.
        • et al.
        Efficacy of autologous platelet-rich plasma use for orthopaedic indications: a meta-analysis.
        J Bone Joint Surg Am. 2012; 94: 298-307
        • Kon E.
        • Mandelbaum B.
        • Buda R.
        • et al.
        Platelet intra-articular injection versus hyaluronic acid viscosupplementation as treatments for cartilage pathology: from early degenerations to osteoarthritis.
        Arthroscopy. 2011; 27: 1490-1501
        • Strauss E.J.
        • Hart J.A.
        • Miller M.D.
        • Altman R.E.
        • Rosen J.E.
        Hyaluronic acid viscosupplementation and osteoarthritis: current uses and future directions.
        Am J Sports Med. 2009; 37: 1636-1644
        • Moher D.
        • Liberati A.
        • Tetzlaff J.
        • Altman D.G.
        • the PRISMA Group
        Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement.
        PLoS Med. 2009; 6: e1000097
      1. Howick J, Chalmers I, Glasziou P, et al. The 2011 Oxford CEBM Evidence Levels of Evidence (Introductory Document). Oxford Centre for Evidence-Based Medicine. Available at: Accessed June 1, 2015.

        • Harris J.D.
        • Quatman C.E.
        • Manring M.M.
        • Siston R.A.
        • Flanigan D.C.
        How to write a systematic review.
        Am J Sports Med. 2014; 42: 2761-2768
        • Slavin R.E.
        Best evidence synthesis: an intelligent alternative to metaanalysis.
        J Clin Epidemiol. 1995; 48: 9-18
        • Editorial Board of the Cochrane Collaboration Back Review Group
        Updated method guidelines for systematic reviews in the cochrane collaboration back review group.
        Spine. 2003; 28: 1290-1299
      2. Owens DK, Lohr KN, Atkins D, et al. Grading the strength of a body of evidence when comparing medical interventions. In: Agency for Healthcare Research and Quality. Methods Guide for Comparative Effectiveness Reviews (posted July 2009). Rockville, MD. Available at: Accessed June 1, 2015.

        • Cowan J.
        • Lozano-Calderon S.
        • Ring D.
        Quality of prospective controlled randomized trials. analysis of trials of treatment for lateral epicondylitis as an example.
        J Bone Joint Surg Am. 2007; 89: 1693-1699
      3. AOSSM Outcomes Task Force, Irrgang J. Summary of clinical outcomes measure for sports-related knee injuries. Available at: Accessed March 1, 2015.

        • DeLong J.M.
        • Russell R.P.
        • Mazzocca A.D.
        Platelet-rich plasma: the PAW classification system.
        J Arthroscopy Related Surg. 2012; 28: 998-1009
        • Ebell M.H.
        • Siwek J.
        • Weiss B.D.
        • et al.
        Strength of recommendation taxonomy (SORT): a patient-centered approach to grading evidence in the medical literature.
        Am Fam Physician. 2004; 69: 549-557
        • Cerza F.
        • Carni S.
        • Carcangiu A.
        • et al.
        Comparison between hyaluronic acid and platelet-rich plasma, intra-articular infiltration in the treatment of gonarthrosis.
        Am J Sports Med. 2012; 40: 2822-2827
        • Filardo G.
        • Kon E.
        • Di Martino A.
        • et al.
        Platelet-rich plasma vs hyaluronic acid to treat knee degenerative pathology: study design and preliminary results of a randomized controlled trial.
        BMC Musculoskel Disord. 2012; 13: 229
        • Patel S.
        • Dhillon M.
        • Aggarwal S.
        • Marwaha N.
        • Jain A.
        Treatment with platelet-rich plasma is more effective than placebo for knee osteoarthritis: a prospective, double-blind, randomized trial.
        Am J Sports Med. 2013; 41: 356-364
        • Sanchez M.
        • Fiz N.
        • Azofra J.
        • et al.
        A randomized clinical trial evaluating plasma rich in growth factors (PRGF-Endoret) versus hyaluronic acid in the short-term treatment of symptomatic knee osteoarthritis.
        J Arthroscopy Related Surg. 2012; 28: 1070-1078
        • Vaquerizo V.
        • Plasencia M.A.
        • Arribas I.
        • et al.
        Comparison of intra-articular injections of plasma rich in growth factors (PRGF-Endoret) versus durolane hyaluronic acid in the treatment of patients with symptomatic osteoarthritis: a randomized controlled trial.
        J Arthroscopy Related Surg. 2013; 29: 1635-1643
        • Raeissadat S.A.
        • Rayegani S.M.
        • Hassanabadi H.
        • et al.
        Knee osteoarthritis injection choices: platelet-rich plasma (PRP) versus hyaluronic acid (a one-year randomized clinical trial).
        Clin Med Insights: Arthritis Musculoskel Disord. 2015; 8: 1-8
        • Gobbi A.
        • Karnatzikos G.
        • Mahajan V.
        • Malchira S.
        Platelet-rich plasma treatment in symptomatic patients with knee osteoarthritis: preliminary results in a group of active patients.
        Sports Health. 2012; 4: 162-172
        • Martin P.
        • D’Souza D.
        • Martin J.
        • et al.
        Wound healing in the PU.1 null mouse: tissue repair is not dependent on inflammatory cells.
        Curr Biol. 2003; 13: 1122-1128
        • Dragoo J.L.
        • Braun H.J.
        • Durham J.L.
        • et al.
        Comparison of the acute inflammatory response of two commercial platelet-rich plasma systems in healthy rabbit tendons.
        Am J Sports Med. 2012; 40: 1274-1281
        • Braun H.J.
        • Kim H.J.
        • Chu C.R.
        • Dragoo J.L.
        The effect of platelet-rich plasma formulations and blood products on human synoviocytes: implications for intra-articular injury and therapy.
        Am J Sports Med. 2014; 42: 1204-1210
      4. Riboh JC, Saltzman BM, Yanke AB, Fortier L, Cole BJ. Effect of leukocyte concentration on the efficacy of platelet rich plasma on the treatment of knee osteoarthritis. Am J Sports Med. April 29, 2015; [E-pub ahead of print].