{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T14:27:28Z","timestamp":1792506448211,"version":"4.5.0"},"reference-count":20,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T00:00:00Z","timestamp":1762214400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T00:00:00Z","timestamp":1762214400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100004434","name":"Universit\u00e0 degli Studi di Firenze","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100004434","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Arch Orthop Trauma Surg"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Achieving personalized alignment in total knee arthroplasty (TKA) with conventional instrumentation remains challenging. This study validates a novel trigonometric formula that calculates the exact lateralization needed for the tibial extramedullary guide based on preoperative weight-bearing X-rays.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We retrospectively analysed 196 patients who underwent TKA between November 2018 and June 2023. Inclusion criteria: patients with preoperative weight-bearing AP lower limb X-rays aged 18 or older. Exclusion criteria: previous total hip arthroplasty, those without consent. The formula LAT\u2009=\u2009LENG(S) \u00d7 sin \u03b1 angle calculated tibial guide lateralization, where LAT was the lateralization distance, LENG(S) was the tibial length from radiographs, and \u03b1 angle was the tibial coronal correction angle. The true radiographic lateralization was measured to validate the formula\u2019s accuracy and defined a \u201csafety zone\u201d representing acceptable surgical margins to validate the formula\u2019s accuracy and defined a \u201csafety zone\u201d representing acceptable surgical margins. The Intraclass Correlation Coefficient (ICC) was used to test for the measurement consistency among observers. 95% Clopper-Pearson Confidence Interval was calculated for the frequency of lateralization falling within a \u201csafety zone\u201d. A T-test compared LAT measurements with true radiographic lateralization.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      ICC showed that 97.2% of lateralization measurements fell within the defined \u201csafety cone\u201d (95% CI 93.9\u201398.9%). Inter-observer reliability was high (ICC 0.91). No differences were found between the formula-derived measurements and the true radiographic lateralization. The 95% Clopper-Pearson Confidence Interval was 93.9\u201398.9%. LAT was found to fall outside the safety cone with a total mean of 2.3\u00b0 (range 1\u20135) in 2.8% of the cases, with a mean error in the degree of proximal tibial cut of -0.67\u00b0 (range \u2212 1 - +1). No association between CPAK and cases within or outside the safety cone was found (\u03c7\u00b2= 5.014,\n                      <jats:italic>p<\/jats:italic>\n                      \u2009=\u20090.658).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>This validated trigonometric formula enables surgeons to accurately calculate tibial guide lateralization for personalized alignment using only conventional instrumentation and standard radiographs. The method\u2019s 97.2% accuracy within safe surgical margins supports its use as a reliable preoperative planning tool for personalized TKA alignment without requiring specialized software or robotic assistance.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1007\/s00402-025-06099-x","type":"journal-article","created":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T05:44:51Z","timestamp":1762235091000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Extramedullary tibial guide orientation in TKA personalized alignment: validation of a trigonometric method"],"prefix":"10.1007","volume":"145","author":[{"given":"Rosario Junior","family":"Sagliocco","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Filippo","family":"Leggieri","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrea","family":"Baldini","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Domenico Andrea","family":"Campanacci","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roberto","family":"Civinini","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matteo","family":"Innocenti","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2025,11,4]]},"reference":[{"key":"6099_CR1","doi-asserted-by":"publisher","first-page":"329","DOI":"10.1302\/0301-620X.103B2.BJJ-2020-1050.R1","volume":"103","author":"SJ MacDessi","year":"2021","unstructured":"MacDessi SJ, Griffiths-Jones W, Harris IA, Bellemans J, Chen DB (2021) Coronal plane alignment of the knee (CPAK) classification. 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The Local Ethics Committees reviewed the study protocol and determined that no ethical approval was required, given the purely retrospective and observational nature of the design.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval"}},{"value":"All patients provided informed consent before enrollment in the study.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Informed consent"}}],"article-number":"496"}}