{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T04:50:11Z","timestamp":1791607811764,"version":"4.3.4"},"reference-count":30,"publisher":"BMJ","issue":"10","license":[{"start":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T00:00:00Z","timestamp":1760400000000},"content-version":"unspecified","delay-in-days":13,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["K24 AR072133"],"award-info":[{"award-number":["K24 AR072133"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["R01AR079647"],"award-info":[{"award-number":["R01AR079647"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000069","name":"National Institute of Arthritis and Musculoskeletal and Skin Diseases","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100000069","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2025,8,14]]},"published-print":{"date-parts":[[2025,10]]},"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To identify gait biomechanical characteristics associated with pain and cartilage damage in individuals with patellofemoral joint osteoarthritis (PFJ OA) during a stair descent activity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Cross-sectional observational study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>University-based motion analysis laboratory and musculoskeletal imaging centre.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Participants<\/jats:title>\n                    <jats:p>83 participants entered the study; 66 participants (41 female, 25 male) completed all components required for this analysis. Participants were recruited via electronic health records following clinical knee MRI. Inclusion criteria included MRI-confirmed patellofemoral cartilage lesions using Whole Organ MRI Score (WORMS) gradings (WORMS &gt;1), pain during stair ambulation, body mass index (BMI) \u226435 and informed consent. Exclusion criteria were tibiofemoral abnormalities (WORMS &gt;1), prior knee trauma, gait-altering conditions, MRI contraindications or pregnancy.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Primary and secondary outcome measures<\/jats:title>\n                    <jats:p>Primary outcomes included knee joint kinematics and during stair descent, assessed during three-dimensional motion capture, patient-reported outcomes from the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire and WORMS gradings to assess severity of cartilage abnormalities. Regression analyses were performed to examine correlations of biomechanics, age and BMI with pain and cartilage damage. Analyses were also performed on male and female participants separately.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Significant associations were found between biomechanical characteristics and KOOS scores (pain, symptoms and patellofemoral) as well as cartilage damage. For the whole cohort, greater knee flexion at late stance was linked to worse KOOS scores (\u03b2=0.53\u2009to 0.71, p&lt;0.05), while age was correlated with more severe cartilage damage (\u03b2=0.06, p=0.00). In males, higher sagittal knee moments (\u03b2=\u2212640.21\u2009to \u2212707.59, p&lt;0.05) and lower frontal knee moments (\u03b2=\u2212530.70\u2009to \u2212904.27, p&lt;0.05) were associated with worse KOOS scores, while in females, greater knee flexion (\u03b2=0.79\u2009to 1.1, p&lt;0.05) and abduction (\u03b2=\u22120.15, p=0.02), as well as lower sagittal knee moments (\u03b2=294.26, p=0.01) were linked to more severe cartilage damage and worse KOOS scores.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Altered knee biomechanics during stair descent are linked to worse knee pain, function and cartilage damage in PFJ OA, with sex-specific differences emphasising the need for individualised interventions to address movement abnormalities.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2025-102121","type":"journal-article","created":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T10:25:19Z","timestamp":1760437519000},"page":"e102121","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Predictors of pain and cartilage damage in patellofemoral joint osteoarthritis: stair descent knee kinematics and kinetics"],"prefix":"10.1136","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-8230-0884","authenticated-orcid":false,"given":"Eric","family":"Hammond","sequence":"first","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joshua","family":"Johnson","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"},{"name":"Department of Physical Therapy and Rehabilitation Science, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Titus","family":"Haley","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy and Rehabilitation Science, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jusuk","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew D","family":"Bucknor","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zehra","family":"Akkaya","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Virginie","family":"Kreutzinger","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fei","family":"Jiang","sequence":"additional","affiliation":[{"name":"Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valentina","family":"Pedoia","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sharmila","family":"Majumdar","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard B","family":"Souza","sequence":"additional","affiliation":[{"name":"Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA"},{"name":"Department of Physical Therapy and Rehabilitation Science, University of California San Francisco, San Francisco, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2025,10,14]]},"reference":[{"key":"2025120415063110000_15.10.e102121.1","doi-asserted-by":"publisher","DOI":"10.5792\/ksrr.2016.28.3.219"},{"key":"2025120415063110000_15.10.e102121.2","doi-asserted-by":"publisher","DOI":"10.1016\/j.joca.2009.03.016"},{"key":"2025120415063110000_15.10.e102121.3","doi-asserted-by":"publisher","DOI":"10.1016\/j.joca.2013.02.003"},{"key":"2025120415063110000_15.10.e102121.4","doi-asserted-by":"publisher","DOI":"10.2519\/jospt.2015.5859"},{"key":"2025120415063110000_15.10.e102121.5","doi-asserted-by":"crossref","first-page":"1554","DOI":"10.1016\/j.joca.2016.04.006","article-title":"Associations between patellofemoral joint cartilage T 1\u03c1 and T 2 and knee flexion moment and impulse during gait in individuals with and without patellofemoral joint osteoarthritis","volume":"24","author":"Teng","year":"2016","journal-title":"Osteoarthr Cartil"},{"key":"2025120415063110000_15.10.e102121.6","doi-asserted-by":"crossref","first-page":"2593","DOI":"10.1002\/jor.24433","article-title":"Association Between Gait Kinetics and Symptomatic Progression in Persons With Patellofemoral With\/Without Concurrent Tibiofemoral Osteoarthritis","volume":"37","author":"Liao","year":"2019","journal-title":"J Orthop Res"},{"key":"2025120415063110000_15.10.e102121.7","doi-asserted-by":"crossref","first-page":"664","DOI":"10.1016\/j.clinbiomech.2014.04.008","article-title":"The relationship between knee joint loading rate during walking and degenerative changes on magnetic resonance imaging","volume":"29","author":"Morgenroth","year":"2014","journal-title":"Clin Biomech (Bristol)"},{"key":"2025120415063110000_15.10.e102121.8","doi-asserted-by":"publisher","DOI":"10.1136\/bjsports-2017-098717"},{"key":"2025120415063110000_15.10.e102121.9","doi-asserted-by":"crossref","first-page":"507","DOI":"10.3390\/biomechanics4030036","article-title":"Effects of Aging on Patellofemoral Joint Stress during Stair Negotiation on Challenging Surfaces","volume":"4","author":"Hunt","year":"2024","journal-title":"Biomechanics (Basel)"},{"key":"2025120415063110000_15.10.e102121.10","unstructured":"Haley T . Biomechanical analysis of patients with patellofemoral joint osteoarthritis during stair descent. n.d. Available: https:\/\/apta.confex.com\/apta\/csm2025\/meetingapp.cgi\/Paper\/46467"},{"key":"2025120415063110000_15.10.e102121.11","unstructured":"Wagner J . Abnormal gait biomechanics in persons with patellofemoral osteoarthritis and movement-evoked pain flares. n.d. Available: https:\/\/apta.confex.com\/apta\/csm2025\/meetingapp.cgi\/Paper\/45576"},{"key":"2025120415063110000_15.10.e102121.12","doi-asserted-by":"crossref","first-page":"1591","DOI":"10.1016\/j.joca.2024.09.001","article-title":"The relationships between patellofemoral bone remodeling, cartilage composition, and vertical loading rate: PET\/MRI in isolated patellofemoral osteoarthritis","volume":"32","author":"Bhattacharjee","year":"2024","journal-title":"Osteoarthr Cartil"},{"key":"2025120415063110000_15.10.e102121.13","doi-asserted-by":"publisher","DOI":"10.1136\/bjsports-2016-096776"},{"key":"2025120415063110000_15.10.e102121.14","doi-asserted-by":"crossref","DOI":"10.1186\/1477-7525-1-64","article-title":"The Knee injury and Osteoarthritis Outcome Score (KOOS): from joint injury to osteoarthritis","volume":"1","author":"Roos","year":"2003","journal-title":"Health Qual Life Outcomes"},{"key":"2025120415063110000_15.10.e102121.15","doi-asserted-by":"crossref","first-page":"562","DOI":"10.1002\/jor.25384","article-title":"Association of patella alignment with cartilage relaxation times and self-reported symptoms in individuals with patellofemoral degeneration","volume":"41","author":"Liao","year":"2023","journal-title":"J Orthop Res"},{"key":"2025120415063110000_15.10.e102121.16","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1002\/pmrj.12398","article-title":"Patients with Symptomatic Hip Osteoarthritis Have Altered Kinematics during Stair Ambulation","volume":"13","author":"Popovic","year":"2021","journal-title":"PM R"},{"key":"2025120415063110000_15.10.e102121.17","doi-asserted-by":"publisher","DOI":"10.1016\/j.jbiomech.2005.02.008"},{"key":"2025120415063110000_15.10.e102121.18","unstructured":"Portney LG , Watkins MP . Foundations of Clinical Research: Applications to Practice. Prenctice Hall, Upper Saddle River (N.J, 2000."},{"key":"2025120415063110000_15.10.e102121.19","doi-asserted-by":"publisher","DOI":"10.1002\/art.10652"},{"key":"2025120415063110000_15.10.e102121.20","doi-asserted-by":"publisher","DOI":"10.1016\/j.clinbiomech.2015.02.008"},{"key":"2025120415063110000_15.10.e102121.21","doi-asserted-by":"crossref","first-page":"715","DOI":"10.2106\/00004623-198466050-00010","article-title":"Patellofemoral contact pressures. The influence of q-angle and tendofemoral contact","volume":"66","author":"Huberti","year":"1984","journal-title":"J Bone Joint Surg Am"},{"key":"2025120415063110000_15.10.e102121.22","doi-asserted-by":"publisher","DOI":"10.1136\/bjsports-2021-104686"},{"key":"2025120415063110000_15.10.e102121.23","doi-asserted-by":"publisher","DOI":"10.1136\/ard.2010.129742"},{"key":"2025120415063110000_15.10.e102121.24","doi-asserted-by":"publisher","DOI":"10.1002\/art.20348"},{"key":"2025120415063110000_15.10.e102121.25","doi-asserted-by":"crossref","first-page":"242","DOI":"10.1016\/j.joca.2016.10.004","article-title":"Association of baseline knee sagittal dynamic joint stiffness during gait and 2-year patellofemoral cartilage damage worsening in knee osteoarthritis","volume":"25","author":"Chang","year":"2017","journal-title":"Osteoarthr Cartil"},{"key":"2025120415063110000_15.10.e102121.26","doi-asserted-by":"crossref","first-page":"105858","DOI":"10.1016\/j.clinbiomech.2022.105858","article-title":"The biomechanical fingerprint of hip and knee osteoarthritis patients during activities of daily living","volume":"101","author":"Van Rossom","year":"2023","journal-title":"Clin Biomech (Bristol)"},{"key":"2025120415063110000_15.10.e102121.27","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/j.plrev.2024.02.003","article-title":"The interplay between biochemical mediators and mechanotransduction in chondrocytes: Unravelling the differential responses in primary knee osteoarthritis","volume":"48","author":"Segarra-Queralt","year":"2024","journal-title":"Phys Life Rev"},{"key":"2025120415063110000_15.10.e102121.28","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1080\/14038190802425575","article-title":"Limb support in response to balance provocations in women with patellofemoral pain","volume":"11","author":"Stensdotter","year":"2009","journal-title":"Adv Physiother"},{"key":"2025120415063110000_15.10.e102121.29","doi-asserted-by":"publisher","DOI":"10.1016\/j.joca.2009.08.010"},{"key":"2025120415063110000_15.10.e102121.30","doi-asserted-by":"crossref","first-page":"300","DOI":"10.1016\/j.joca.2022.10.023","article-title":"Association between weight gain and knee osteoarthritis: a systematic review","volume":"31","author":"Solanki","year":"2023","journal-title":"Osteoarthr Cartil"}],"container-title":["BMJ Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bmjopen-2025-102121","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,4]],"date-time":"2025-12-04T23:09:29Z","timestamp":1764889769000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmjopen.bmj.com\/lookup\/doi\/10.1136\/bmjopen-2025-102121"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10]]},"references-count":30,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2025,10,14]]},"published-print":{"date-parts":[[2025,10]]}},"alternative-id":["10.1136\/bmjopen-2025-102121"],"URL":"https:\/\/doi.org\/10.1136\/bmjopen-2025-102121","relation":{},"ISSN":["2044-6055","2044-6055"],"issn-type":[{"value":"2044-6055","type":"print"},{"value":"2044-6055","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10]]}}}