{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T18:04:48Z","timestamp":1789581888133,"version":"build-2803163510"},"reference-count":15,"publisher":"Open Medical Publishing","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"\n Background<\/jats:title>\n Platelet-rich plasma (PRP) is used as an orthobiologic injection therapy for knee osteoarthritis (OA), but reported outcomes vary according to PRP formulation, injection protocol, comparator, and patient selection. Real-world data describing the Zimmer Biomet GPS leukocyte-rich PRP system in Japanese clinical practice remain limited.<\/jats:p>\n <\/jats:sec>\n \n Purpose<\/jats:title>\n To describe 1-year patient-reported outcomes after a single intra-articular GPS leukocyte-rich PRP injection in patients with Kellgren-Lawrence (KL) grade II or III knee OA.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n This retrospective single-center case series included patients with symptomatic Kellgren-Lawrence (KL) grade II or III knee osteoarthritis (OA) who underwent GPS leukocyte-rich platelet-rich plasma (PRP) injection. During the study period, 20 patients\/knees received an initial GPS L-PRP injection; 5 could not be followed at 1 year and were excluded from the paired 1-year analysis. The final analysis included 15 knees with paired baseline and 1-year numeric rating scale (NRS) pain data. Radiography and magnetic resonance imaging were used to support baseline diagnosis and eligibility; MRI was not analyzed as a longitudinal structural outcome. The primary outcome was change in NRS pain. Secondary outcomes included Knee injury and Osteoarthritis Outcome Score (KOOS), Locomo-25, responder status, and adverse events.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n Of 20 patients\/knees treated with an initial GPS L-PRP injection, 5 were lost to 1-year follow-up or had unavailable 1-year outcome data; 15 knees from 5 male and 10 female patients were included in the final paired analysis. NRS pain improved from 4.6 \u00b1 2.4 at baseline to 2.7 \u00b1 2.1 at 1 year (mean change, -1.9 points; 95% CI, -3.4 to -0.4; P = 0.015). KOOS quality of life improved from 30.0 \u00b1 17.1 to 45.4 \u00b1 23.8 (mean change, 15.4 points; 95% CI, 4.8 to 26.0; P = 0.010). Other KOOS domains and Locomo-25 showed numerical improvement but did not reach statistical significance. A \u226530% NRS pain reduction occurred in 7 of 15 knees (46.7%), and pain worsened in 2 of 15 knees (13.3%).<\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n In this small uncontrolled retrospective case series, GPS leukocyte-rich PRP injection was associated with improved NRS pain and KOOS quality of life at 1 year. These findings should be interpreted as preliminary observational associations and cannot establish treatment efficacy or safety. Larger prospective controlled studies with standardized PRP characterization are needed.<\/jats:p>\n <\/jats:sec>","DOI":"10.52965\/001c.169123","type":"journal-article","created":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T17:46:34Z","timestamp":1789580794000},"source":"Crossref","is-referenced-by-count":0,"title":["Preliminary One-Year Observational Outcomes After GPS Leukocyte-Rich Platelet-Rich Plasma Injection for Kellgren-Lawrence Grade II and III Knee Osteoarthritis: A Japanese Real-World Case Series"],"prefix":"10.52965","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7708-1660","authenticated-orcid":true,"given":"Hiroyuki","family":"Maeda","sequence":"first","affiliation":[{"name":"Yamamoto & Maeda Memorial Maeda Hospital, Department of Orthopaedics and Anesthesia, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takahiro","family":"Maeda","sequence":"additional","affiliation":[{"name":"Yamamoto & Maeda Memorial Maeda Hospital, Department of Orthopaedics and Anesthesia, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mutsuhiro","family":"Maeda","sequence":"additional","affiliation":[{"name":"Yamamoto & Maeda Memorial Maeda Hospital, Department of Orthopaedics and Anesthesia, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"30777","published-online":{"date-parts":[[2026,9,16]]},"reference":[{"issue":"1","key":"ref1","doi-asserted-by":"publisher","first-page":"249","DOI":"10.1177\/0363546520909397","article-title":"Platelet-rich plasma versus hyaluronic acid for knee osteoarthritis: a systematic review and meta-analysis of randomized controlled trials","volume":"49","author":"J. 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Kim","year":"2021","journal-title":"Orthop J Sports Med"},{"issue":"9","key":"ref7","doi-asserted-by":"publisher","first-page":"1137","DOI":"10.1016\/j.joca.2009.04.005","article-title":"Prevalence of radiographic knee osteoarthritis and its association with knee pain in the elderly of Japanese population-based cohorts: the ROAD study","volume":"17","author":"S. Muraki","year":"2009","journal-title":"Osteoarthritis Cartilage"},{"issue":"3","key":"ref8","doi-asserted-by":"publisher","first-page":"86","DOI":"10.1016\/j.afos.2018.09.004","article-title":"Locomotive syndrome in Japan","volume":"4","author":"H. Ishibashi","year":"2018","journal-title":"Osteoporos Sarcopenia"},{"issue":"3","key":"ref9","doi-asserted-by":"publisher","first-page":"363","DOI":"10.1016\/j.joca.2014.01.003","article-title":"OARSI guidelines for the non-surgical management of knee osteoarthritis","volume":"22","author":"T. E. 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Smith","year":"2016","journal-title":"Am J Sports Med"},{"issue":"2","key":"ref12","doi-asserted-by":"publisher","first-page":"339","DOI":"10.1177\/0363546516665809","article-title":"Hyaluronic acid versus platelet-rich plasma: a prospective, double-blind randomized controlled trial comparing clinical outcomes and effects on intra-articular biology for the treatment of knee osteoarthritis","volume":"45","author":"B. J. Cole","year":"2017","journal-title":"Am J Sports Med"},{"issue":"4","key":"ref13","doi-asserted-by":"publisher","first-page":"472","DOI":"10.1007\/s00167-009-0940-8","article-title":"Platelet-rich plasma: intra-articular knee injections produced favorable results on degenerative cartilage lesions","volume":"18","author":"E. Kon","year":"2010","journal-title":"Knee Surg Sports Traumatol Arthrosc"},{"issue":"10","key":"ref14","doi-asserted-by":"publisher","first-page":"657","DOI":"10.1136\/bjsports-2014-094036","article-title":"Efficacy of platelet-rich plasma injections in osteoarthritis of the knee: a systematic review and meta-analysis","volume":"49","author":"A. B. M. Laudy","year":"2015","journal-title":"Br J Sports Med"},{"issue":"3","key":"ref15","doi-asserted-by":"publisher","first-page":"659","DOI":"10.1016\/j.arthro.2016.09.024","article-title":"Efficacy of platelet-rich plasma in the treatment of knee osteoarthritis: a meta-analysis of randomized controlled trials","volume":"33","author":"W. L. Dai","year":"2017","journal-title":"Arthroscopy"}],"container-title":["Orthopedic Reviews"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/orthopedicreviews.openmedicalpublishing.org\/article\/169123-preliminary-one-year-observational-outcomes-after-gps-leukocyte-rich-platelet-rich-plasma-injection-for-kellgren-lawrence-grade-ii-and-iii-knee-osteoa","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T17:46:35Z","timestamp":1789580795000},"score":1,"resource":{"primary":{"URL":"https:\/\/orthopedicreviews.openmedicalpublishing.org\/article\/169123-preliminary-one-year-observational-outcomes-after-gps-leukocyte-rich-platelet-rich-plasma-injection-for-kellgren-lawrence-grade-ii-and-iii-knee-osteoa"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,16]]},"references-count":15,"URL":"https:\/\/doi.org\/10.52965\/001c.169123","relation":{},"ISSN":["2035-8164"],"issn-type":[{"value":"2035-8164","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,16]]}}}