{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T03:41:31Z","timestamp":1792467691269,"version":"4.5.0"},"reference-count":26,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T00:00:00Z","timestamp":1792368000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T00:00:00Z","timestamp":1792368000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["esskajournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Knee surg. sports traumatol. arthrosc."],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>Natural knee joint line orientation (JLO) relative to the ground remains poorly understood. A JLO parallel to the floor is commonly assumed to favour balanced medial\u2010lateral compartment loading, but the independent influence of femoral and tibial coronal anatomy on JLO during bipodal and single\u2010limb stance has not been quantified. This study aimed to quantify the independent effects of the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA) on knee JLO relative to the ground during bipodal and single\u2010limb stance using a mathematical model.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A two\u2010dimensional geometric model of the lower limb was developed using representative anthropometric parameters. MPTA and LDFA were varied independently across the native varus\u2010valgus range, from neutral to 7\u00b0, in 1\u00b0 increments, yielding 36 discrete anatomical configurations. For each configuration, knee JLO relative to the ground was calculated for bipodal and single\u2010limb stance, along with the theoretical mediolateral centre of mass (COM) displacement required to achieve a horizontal JLO. The model is deterministic and closed\u2010form; results are reported to 0.1\u00b0 and 0.1\u2009mm.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Transition from bipodal to single\u2010limb stance reduced JLO by 2.6\u00b0 regardless of coronal anatomy. Each 1\u00b0 change in MPTA or LDFA altered JLO by approximately 0.5\u00b0 (0.54\u00b0 and 0.46\u00b0 per degree, respectively), indicating comparable effect magnitudes for tibial and femoral anatomy. However, MPTA and LDFA produced distinct geometric relationships, yielding different JLOs despite identical hip\u2013knee\u2013ankle alignment. Only a limited subset of configurations produced a horizontal JLO without theoretical COM displacement.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Femoral and tibial coronal anatomy independently and predictably influence knee JLO during bipodal and single\u2010limb stance, and overall alignment alone does not predict JLO. Achieving a horizontal JLO would require substantial COM adaptation in most configurations. Whether a horizontal JLO is physiologically achievable, or the primary biomechanical objective in all individuals, remains unknown.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Level of Evidence<\/jats:title>\n                    <jats:p>Level V.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/ksa.70653","type":"journal-article","created":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T03:26:03Z","timestamp":1792466763000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A mathematical model of knee joint line orientation: Independent effects of femoral and tibial coronal anatomy and limits on achieving a horizontal joint line"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7519-4995","authenticated-orcid":false,"given":"Gautier","family":"Beckers","sequence":"first","affiliation":[{"name":"Surgery Department Universit\u00e9 de Montr\u00e9al Montr\u00e9al Qu\u00e9bec Canada"},{"name":"Personalized Arthroplasty Society Atlanta Georgia USA"},{"name":"Surgery Department H\u00f4pital Maisonneuve\u2010Rosemont Montreal Qu\u00e9bec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mathias","family":"Hengartner","sequence":"additional","affiliation":[{"name":"Surgery Department Universit\u00e9 de Montr\u00e9al Montr\u00e9al Qu\u00e9bec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marin","family":"Lavigne","sequence":"additional","affiliation":[{"name":"Personalized Arthroplasty Society Atlanta Georgia USA"},{"name":"Surgery Department H\u00f4pital Maisonneuve\u2010Rosemont Montreal Qu\u00e9bec Canada"},{"name":"Clinique Orthop\u00e9dique Duval Laval Qu\u00e9bec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marc\u2010Olivier","family":"Kiss","sequence":"additional","affiliation":[{"name":"Surgery Department Universit\u00e9 de Montr\u00e9al Montr\u00e9al Qu\u00e9bec Canada"},{"name":"Personalized Arthroplasty Society Atlanta Georgia USA"},{"name":"Surgery Department H\u00f4pital Maisonneuve\u2010Rosemont Montreal Qu\u00e9bec Canada"},{"name":"Clinique Orthop\u00e9dique Duval Laval Qu\u00e9bec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vincent","family":"Mass\u00e9","sequence":"additional","affiliation":[{"name":"Surgery Department Universit\u00e9 de Montr\u00e9al Montr\u00e9al Qu\u00e9bec Canada"},{"name":"Personalized Arthroplasty Society Atlanta Georgia USA"},{"name":"Surgery Department H\u00f4pital Maisonneuve\u2010Rosemont Montreal Qu\u00e9bec Canada"},{"name":"Clinique Orthop\u00e9dique Duval Laval Qu\u00e9bec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4652-6238","authenticated-orcid":false,"given":"Pascal\u2010Andr\u00e9","family":"Vendittoli","sequence":"additional","affiliation":[{"name":"Surgery Department Universit\u00e9 de Montr\u00e9al Montr\u00e9al Qu\u00e9bec Canada"},{"name":"Personalized Arthroplasty Society Atlanta Georgia USA"},{"name":"Clinique Orthop\u00e9dique Duval Laval Qu\u00e9bec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,10,19]]},"reference":[{"key":"e_1_2_13_2_1","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1016\/j.gaitpost.2016.06.020","article-title":"Single leg stance control in individuals with symptomatic gluteal tendinopathy","volume":"49","author":"Allison K","year":"2016","journal-title":"Gait Posture"},{"key":"e_1_2_13_3_1","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1016\/j.gaitpost.2018.02.011","article-title":"Gluteal tendinopathy and hip osteoarthritis: Different pathologies, different hip biomechanics","volume":"61","author":"Allison K","year":"2018","journal-title":"Gait 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In press.","DOI":"10.1002\/ksa.70403"},{"issue":"3","key":"e_1_2_13_9_1","doi-asserted-by":"crossref","first-page":"515","DOI":"10.1002\/ksa.12107","article-title":"Neutrality, normality, abnormality and pathology in coronal knee alignment: why and how should we define it in the era of personalised medicine?","volume":"32","author":"Hirschmann MT","year":"2024","journal-title":"Knee Surg Sports Traumatol Arthrosc"},{"issue":"5","key":"e_1_2_13_10_1","doi-asserted-by":"crossref","first-page":"1394","DOI":"10.1007\/s00167-019-05509-z","article-title":"Functional knee phenotypes: a novel classification for phenotyping the coronal lower limb alignment based on the native alignment in young non\u2010osteoarthritic patients","volume":"27","author":"Hirschmann MT","year":"2019","journal-title":"Knee Surg Sports Traumatol Arthrosc"},{"issue":"3","key":"e_1_2_13_11_1","doi-asserted-by":"crossref","first-page":"1000","DOI":"10.1007\/s11999-012-2613-z","article-title":"Does a kinematically aligned total knee arthroplasty restore function without failure regardless of alignment category?","volume":"471","author":"Howell SM","year":"2013","journal-title":"Clin Orthop Relat Res"},{"issue":"1","key":"e_1_2_13_12_1","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1007\/s00264-015-2733-7","article-title":"Functional joint line obliquity after kinematic total knee arthroplasty","volume":"40","author":"Hutt J","year":"2016","journal-title":"Int Orthop"},{"issue":"1","key":"e_1_2_13_13_1","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.gaitpost.2013.06.004","article-title":"How gravity and muscle action control mediolateral center of mass excursion during slow walking: a simulation study","volume":"39","author":"Jansen K","year":"2014","journal-title":"Gait Posture"},{"issue":"8","key":"e_1_2_13_14_1","doi-asserted-by":"crossref","first-page":"2436","DOI":"10.1007\/s00167-016-3995-3","article-title":"Kinematically aligned TKA can align knee joint line to horizontal","volume":"24","author":"Ji H\u2010M","year":"2016","journal-title":"Knee Surg Sports Traumatol Arthrosc"},{"issue":"1","key":"e_1_2_13_15_1","doi-asserted-by":"crossref","first-page":"458","DOI":"10.1186\/s12891-026-09980-x","article-title":"Automated assessment of coronal lower extremity alignment on long\u2010leg radiographs using a deep\u2010learning model: validation, efficiency gains, and superiority of an edge\u2010based tibial joint\u2010line definition","volume":"27","author":"Jin W","year":"2026","journal-title":"BMC Musculoskelet Disord"},{"issue":"1","key":"e_1_2_13_16_1","doi-asserted-by":"crossref","DOI":"10.1038\/s41598-019-55432-z","article-title":"Analysis of 1.2 million foot scans from North America, Europe and Asia","volume":"9","author":"Jurca A","year":"2019","journal-title":"Sci Rep"},{"issue":"7","key":"e_1_2_13_17_1","doi-asserted-by":"crossref","first-page":"889","DOI":"10.1302\/0301-620X.108B7.BJJ-2025-0687.R2","article-title":"Coronal alignment parameters of the knee predict osteoarthritis development","volume":"108","author":"Kim J\u2010S","year":"2026","journal-title":"Bone Jt J"},{"issue":"4","key":"e_1_2_13_18_1","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1302\/0301-620X.107B4.BJJ-2024-0204.R3","article-title":"Kinematic alignment achieves a tibial joint line angle that is more parallel to the floor in single\u2010leg stance than mechanical alignment","volume":"107","author":"Leong BJ","year":"2025","journal-title":"Bone Jt J"},{"issue":"5","key":"e_1_2_13_19_1","doi-asserted-by":"crossref","first-page":"640","DOI":"10.1302\/0301-620X.99B5.BJJ-2016-0688.R2","article-title":"Radiological and clinical comparison of kinematically versus mechanically aligned total knee arthroplasty","volume":"99","author":"Matsumoto T","year":"2017","journal-title":"Bone Jt J"},{"issue":"6","key":"e_1_2_13_20_1","doi-asserted-by":"crossref","first-page":"829","DOI":"10.1682\/JRRD.2003.10.0150","article-title":"The effect of walking speed on center of mass displacement","volume":"41","author":"Orendurff MS","year":"2004","journal-title":"J Rehabil Res Dev"},{"key":"e_1_2_13_21_1","doi-asserted-by":"crossref","unstructured":"Pfl\u00fcgerP PedrazziniA FischerL JudL VlachopoulosL FucenteseSF.Joint line obliquity disruption negatively affects mid\u2010term patient\u2010reported outcomes following total knee arthroplasty.Knee Surg Sports Traumatol Arthrosc.2026. 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