{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T12:08:16Z","timestamp":1788955696641,"version":"build-2803163510"},"reference-count":22,"publisher":"MJS Publishing, Medical Journals Sweden AB","license":[{"start":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T00:00:00Z","timestamp":1788912000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ActaO"],"abstract":"<jats:p>Background and purpose:\u00a0We aimed to clarify whether preoperative flexion contracture (FC) and limited knee flexion in patients with anteromedial osteoarthritis (OA) were associated with postoperative outcomes in mobile-bearing medial unicompartmental knee arthroplasty (UKA).Methods:\u00a0We retrospectively evaluated all patients who underwent mobile-bearing medial UKA. Preoperative extension and flexion angles, and the Oxford Knee Score (OKS) and Forgotten Joint Score-12 (FJS) recorded preoperatively and at 3, 12, and 24 months, were assessed. Patients were categorized by preoperative extension (no FC, &lt; 10\u00b0, \u2265 10\u00b0) and flexion angles (&lt; 120\u00b0, \u2265 120\u00b0). Changes in OKS and FJS were compared using general linear models with adjustment for age, sex, body mass index, and preoperative scores.Results:\u00a01,199 patients were included. Preoperatively, 85% of patients had full extension, 12% had &lt; 10\u00b0 FC, and 3.1% had \u2265 10\u00b0 FC. Regarding flexion, 40% had &lt; 120\u00b0, while 60% had \u2265 120\u00b0. At 12 months, the &lt; 10\u00b0 FC group showed greater improvements than the \u2265 10\u00b0 FC group in OKS (adjusted mean difference, 5.5 points; 95% confidence interval [CI] 0.9\u201310.2; P = 0.01) and FJS (17.0 points; CI 1.0\u201333.0; P = 0.03). The &lt; 120\u00b0 flexion group showed greater FJS improvement than the \u2265 120\u00b0 flexion group (adjusted mean difference, 4.8 points; CI 0.1\u20139.6; P = 0.045). At 24 months, the CIs for all between-group differences included no difference.Conclusion:\u00a0Mild preoperative FC and mild-to-moderately limited knee flexion were not associated with inferior outcomes. Patients with more pronounced FC showed slower recovery but still achieved the same increase in patient-reported outcome measures (PROMs) as those with mild FC.<\/jats:p>","DOI":"10.2340\/17453674.2026.46721","type":"journal-article","created":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T11:39:27Z","timestamp":1788953967000},"source":"Crossref","is-referenced-by-count":0,"title":["Association of preoperative flexion contracture and limited knee flexion with short-term patient-reported outcomes after medial unicompartmental knee arthroplasty"],"prefix":"10.2340","volume":"97","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6469-4652","authenticated-orcid":false,"given":"Tomofumi","family":"Kinoshita","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristine Ifigenia","family":"Bunyoz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8174-4965","authenticated-orcid":false,"given":"Kristian R L","family":"Mortensen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6984-6782","authenticated-orcid":false,"given":"Christian Bredgaard","family":"Jensen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian S","family":"Nielsen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8114-5193","authenticated-orcid":false,"given":"Kirill","family":"Gromov","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0132-8182","authenticated-orcid":false,"given":"Anders","family":"Troelsen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1183","published-online":{"date-parts":[[2026,9,9]]},"reference":[{"key":"167859","doi-asserted-by":"crossref","unstructured":"Kozinn S C, Scott R. 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Chronic pain after primary total and medial unicompartmental knee arthroplasty for osteoarthritis: a Danish nationwide cross-sectional survey. Acta Orthop 2025; 27; 96: 814-821. doi: 10.2340\/17453674.2025.44898.","DOI":"10.2340\/17453674.2025.44898"},{"key":"167863","doi-asserted-by":"crossref","unstructured":"Nakano N, Tsubosaka M, Kamenaga T, Kuroda Y, Ishida K, Hayashi S, et al. What effect does preoperative flexion contracture have on the component angles in unicompartmental knee arthroplasty? Eur J Orthop Surg Traumatol 2024; 34: 2185-91. doi: 10.1007\/s00590-024-03929-3.","DOI":"10.1007\/s00590-024-03929-3"},{"key":"167864","doi-asserted-by":"crossref","unstructured":"Yeh J Z Y, Chen J Y, Lim J W, Pang H N, Tay D K J, Chia S L, et al. Postoperative fixed flexion deformity greater than 10\u00b0 lead to poorer functional outcome 10 years after unicompartmental knee arthroplasty. 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The use of the Oxford hip and knee scores. J Bone Joint Surg Br 2007; 89: 1010-4. doi: 10.1302\/0301-620X.89B8.19424.","DOI":"10.1302\/0301-620X.89B8.19424"},{"key":"167868","doi-asserted-by":"crossref","unstructured":"Behrend H, Giesinger K, Giesinger J M, Kuster M S. The \u201cforgotten joint\u201d as the ultimate goal in joint arthroplasty: validation of a new patient-reported outcome measure. J Arthroplasty 2012; 27: 430-436.e1. doi: 10.1016\/j.arth.2011.06.035.","DOI":"10.1016\/j.arth.2011.06.035"},{"key":"167869","doi-asserted-by":"crossref","unstructured":"Beard D J, Harris K, Dawson J, Doll H, Murray D W, Carr A J, et al. Meaningful changes for the Oxford hip and knee scores after joint replacement surgery. J Clin Epidemiol 2015; 68: 73-79. https:\/\/doi.org\/10.1016\/j.jclinepi.2014.08.009.","DOI":"10.1016\/j.jclinepi.2014.08.009"},{"key":"167870","doi-asserted-by":"crossref","unstructured":"Longo U G, De Salvatore S, Candela V, Berton A, Casciaro C, Sciotti G, et al. 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Is simultaneous bilateral unicompartmental knee arthroplasty and total knee arthroplasty better than simultaneous bilateral total knee arthroplasty? Knee Surg Relat Res 2023; 35: 12. doi: 10.1186\/s43019-023-00183-5.","DOI":"10.1186\/s43019-023-00183-5"},{"key":"167876","doi-asserted-by":"crossref","unstructured":"Zhou J, Zhao F, Chen C, Li Y, Liu X, Wang P, et al. Influencing factors of flexion contracture among patients with knee osteoarthritis: a multi-center retrospective cross-sectional study. Sci Rep 2025; 15: 32144. doi: 10.1038\/s41598-025-17763-y.","DOI":"10.1038\/s41598-025-17763-y"},{"key":"167877","doi-asserted-by":"crossref","unstructured":"Holst D C, Doan G W, Angerame M R, Roche M W, Clary C W, Dennis D A. What is the effect of posterior osteophytes on flexion and extension gaps in total knee arthroplasty? A cadaveric study. 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