{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T05:06:21Z","timestamp":1779339981102,"version":"3.51.4"},"reference-count":23,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T00:00:00Z","timestamp":1778716800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Unicompartmental knee arthroplasty (UKA) is an effective treatment for anteromedial osteoarthritis in carefully selected patients. Increasing attention has recently been directed toward restoration of pre-arthritic coronal alignment, supported by the use of the arithmetic hip\u2013knee\u2013ankle angle (aHKA) to estimate constitutional lower limb alignment. In medial UKA, kinematic alignment principles derived from the original technique described by Cartier et al. may help to reproduce native joint-line orientation while preserving physiological soft-tissue balance. This technical note details the indications, preoperative assessment, planning strategy, and operative steps of the procedure. Preoperative long-leg weight-bearing radiographs are used to estimate constitutional alignment through the aHKA and to plan the coronal inclination of the tibial cut. Intraoperatively, the distal position of the extramedullary guide is reproduced according to the preoperative planning in order to restore the native inclination of the medial tibial plateau. The sagittal tibial cut, posterior tibial slope, distal femoral cut, component sizing, gap assessment, and cementation technique are described, with emphasis on anatomical landmarks and technical pearls to improve reproducibility. The described technique provides a practical method for approximating constitutional coronal alignment in medial UKA without the use of robotic or navigated systems. The key feature of the procedure is accurate planning and execution of the tibial cut in both the coronal and sagittal planes in order to reproduce native joint-line orientation and preserve appropriate ligament balance.<\/jats:p>","DOI":"10.3390\/jcm15103797","type":"journal-article","created":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T16:27:56Z","timestamp":1778776076000},"page":"3797","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Personalized Tibial Component Placement in Medial Unicompartmental Knee Arthroplasty: Surgical Technique and Rationale"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-4862-7197","authenticated-orcid":false,"given":"Paolo","family":"Queirazza","sequence":"first","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy"},{"name":"Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6342-2740","authenticated-orcid":false,"given":"Marco","family":"Minelli","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy"},{"name":"Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesco","family":"Cacace","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy"},{"name":"Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0649-2336","authenticated-orcid":false,"given":"Elizaveta","family":"Kon","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy"},{"name":"Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Enrico","family":"Arnaldi","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3760-3409","authenticated-orcid":false,"given":"Marco","family":"Basso","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"582","DOI":"10.1302\/0301-620X.73B4.2071640","article-title":"Anteromedial osteoarthritis of the knee","volume":"73","author":"White","year":"1991","journal-title":"J. Bone Jt. Surg. Br."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"331","DOI":"10.23736\/S2784-8469.24.04425-0","article-title":"Gonarthrosis and ACL lesion: An intraoperative analysis and correlations in patients who underwent total knee arthroplasty","volume":"75","author":"Passaretti","year":"2024","journal-title":"Minerva Orthop."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1460","DOI":"10.1016\/j.arth.2016.12.014","article-title":"Outcome of Unicondylar Knee Arthroplasty vs. Total Knee Arthroplasty for Early Medial Compartment Arthritis: A Randomized Study","volume":"32","author":"Kulshrestha","year":"2017","journal-title":"J. Arthroplast."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1779","DOI":"10.1016\/j.arth.2014.03.043","article-title":"Oxford Unicompartmental Knee Arthroplasty Versus Age and Gender Matched Total Knee Arthroplasty\u2014Functional Outcome and Survivorship Analysis","volume":"29","author":"Lim","year":"2014","journal-title":"J. Arthroplast."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"332","DOI":"10.2106\/JBJS.C.01467","article-title":"Can Normal Knee Kinematics Be Restored with Unicompartmental Knee Replacement?","volume":"87","author":"Patil","year":"2005","journal-title":"JBJS"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1302\/2633-1462.25.BJO-2021-0028.R1","article-title":"Arithmetic hip-knee-ankle angle (aHKA): An algorithm for estimating constitutional lower limb alignment in the arthritic patient population","volume":"2","author":"Chen","year":"2021","journal-title":"Bone Jt. Open"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Liu, C., Huang, C., Suyalatu, X., Zhang, Q., Zhang, Y., Sun, W., Guo, W., and Wang, W. (2025). Optimizing uni-compartmental knee arthroplasty: The impact of preoperative planning and arithmetic hip-knee-ankle angle. BMC Musculoskelet. Disord., 26.","DOI":"10.1186\/s12891-025-08512-3"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1081","DOI":"10.2106\/JBJS.21.00801","article-title":"Pre-Arthritic\/Kinematic Alignment in Fixed-Bearing Medial Unicompartmental Knee Arthroplasty Results in Return to Activity at Mean 10-Year Follow-up","volume":"104","author":"Plancher","year":"2022","journal-title":"JBJS"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1423","DOI":"10.1111\/os.12927","article-title":"Impact of Tibial Component Coronal Alignment on Knee Joint Biomechanics Following Fixed-bearing Unicompartmental Knee Arthroplasty: A Finite Element Analysis","volume":"13","author":"Nie","year":"2021","journal-title":"Orthop. Surg."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"434","DOI":"10.1016\/j.knee.2018.02.004","article-title":"How does the inclination of the tibial component matter? A three-dimensional finite element analysis of medial mobile-bearing unicompartmental arthroplasty","volume":"25","author":"Dai","year":"2018","journal-title":"Knee"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"782","DOI":"10.1016\/S0883-5403(96)80177-X","article-title":"Unicompartmental knee arthroplasty surgery: 10-Year minimum follow-up period","volume":"11","author":"Cartier","year":"1996","journal-title":"J. Arthroplast."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1016\/j.knee.2014.12.004","article-title":"Minor varus alignment provides better results than neutral alignment in medial UKA","volume":"22","author":"Vasso","year":"2015","journal-title":"Knee"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"100334","DOI":"10.1016\/j.jisako.2024.100334","article-title":"Unicompartmental Knee Arthroplasty: What is the optimal alignment correction to achieve success? The role of kinematic alignment","volume":"9","author":"McEwen","year":"2024","journal-title":"J. ISAKOS"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"506","DOI":"10.2106\/00004623-200403000-00007","article-title":"Posterior Slope of the Tibial Implant and the Outcome of Unicompartmental Knee Arthroplasty","volume":"86","author":"Hernigou","year":"2004","journal-title":"JBJS"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"S219","DOI":"10.1016\/j.otsr.2013.03.004","article-title":"Medial unicompartmental knee arthroplasty: Does tibial component position influence clinical outcomes and arthroplasty survival?","volume":"99","author":"Chatellard","year":"2013","journal-title":"Orthop. Traumatol. Surg. Res."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Parratte, S., Daxhelet, J., Argenson, J.N., and Batailler, C. (2023). The Deep-MCL Line: A Reliable Anatomical Landmark to Optimize the Tibial Cut in UKA. J. Pers. Med., 13.","DOI":"10.3390\/jpm13050855"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1269","DOI":"10.1016\/j.knee.2014.06.008","article-title":"Alignment of the tibial component of the unicompartmental knee arthroplasty, assessed in the axial view by CT scan: Does it influence the outcome?","volume":"21","author":"Iriberri","year":"2014","journal-title":"Knee"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1186\/s40634-023-00655-3","article-title":"Significant correlations between postoperative outcomes and various limb and component alignment strategies in medial unicompartmental knee arthroplasty: A systematic review","volume":"10","author":"Sava","year":"2023","journal-title":"J. Exp. Orthop."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"166","DOI":"10.4055\/cios19011","article-title":"The Medial Eminence Line for Predicting Tibial Fracture Risk after Unicompartmental Knee Arthroplasty","volume":"12","author":"Yoshikawa","year":"2020","journal-title":"Clin. Orthop. Surg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1186\/s43019-025-00299-w","article-title":"Does undersizing of the tibial component in unicompartmental knee arthroplasty increase the risk of fracture? A biomechanical study","volume":"37","author":"Watrinet","year":"2025","journal-title":"Knee Surg. Relat. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"57","DOI":"10.36469\/jheor.2022.37024","article-title":"Robotic-Arm Assisted Technology\u2019s Impact on Knee Arthroplasty and Associated Healthcare Costs","volume":"9","author":"Kolessar","year":"2022","journal-title":"J. Health Econ. Outcomes Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1016\/j.knee.2025.10.004","article-title":"Comparison of implant complications, lengths of stay, and costs among patients undergoing robotic-assisted versus conventional unicompartmental knee arthroplasty","volume":"57","author":"Gordon","year":"2025","journal-title":"Knee"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"101652","DOI":"10.1016\/j.artd.2025.101652","article-title":"Is Robotic-Assisted Unicompartmental Knee Arthroplasty Compared to Manual Unicompartmental Knee Arthroplasty Associated With Decreased Revision Rates? An Updated Matched Cohort Analysis","volume":"32","author":"Guild","year":"2025","journal-title":"Arthroplast. 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