{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:37:27Z","timestamp":1760060247832,"version":"build-2065373602"},"reference-count":35,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2025,8,8]],"date-time":"2025-08-08T00:00:00Z","timestamp":1754611200000},"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>Background: Emerging parameters, such as the spino-pelvic unit and the combined sagittal index (CSI), are gaining importance in evaluating and optimizing implant positioning in total hip arthroplasty (THA). Our institution adopts the \u201cfemur first\u201d technique to achieve the desired combined anteversion (CA). The purpose of this study is to evaluate the role of the \u2018femur first\u2019 technique and spinopelvic characteristics in achieving the CSIstanding \u2018safe zone\u2019 in primary THA. Methods: Consecutive patients undergoing primary THA were included in the present retrospective study. All patients underwent radiographic assessments in the standing position with the EOS 2D\/3D radiography system. Results: Forty patients (40 hips) were enrolled. Of these, 34 patients fell inside the CSIstanding \u201csafe zone\u201d (205\u2013245\u00b0). When considering the restricted CSIstanding \u201csafe zone\u201d for patients at high risk for adverse spinopelvic characteristics (215\u2013245\u00b0), only 16 patients fell inside the range. We demonstrated a positive linear correlation between CSIstanding and CA (p &lt; 0.0001). Pelvic tilt (PT) showed a positive correlation both in standing and relaxed sitting positions, (p &lt; 0.001). Sacral slope (SS) showed a significant positive correlation in the relaxed sitting (p = 0.003) position but not in the standing position (p = 0.34). The correlation analysis between CSIrelaxed-sitting and \u0394SS showed a positive correlation (p = 0.003). Conclusions: The \u201cfemur first\u201d technique is able to achieve the CSI \u201csafe zone\u201d in most patients; however, it seems insufficient in those with adverse spinopelvic characteristics, who are at higher risk of dislocation. Moreover, the CA, the position of the pelvis in space (PT), and its mobility (\u0394SS) greatly influence the CSI \u201csafe zone\u201d in patients undergoing primary THA.<\/jats:p>","DOI":"10.3390\/jcm14165620","type":"journal-article","created":{"date-parts":[[2025,8,8]],"date-time":"2025-08-08T13:20:09Z","timestamp":1754659209000},"page":"5620","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Role of the \u2018Femur First\u2019 Technique and Spinopelvic Characteristics in Achieving the Combined Sagittal Index in Total Hip Arthroplasty: Results from a Retrospective Tertiary-Center Clinical Study"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0102-2095","authenticated-orcid":false,"given":"Edoardo","family":"Guazzoni","sequence":"first","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9327-5350","authenticated-orcid":false,"given":"Giuseppe","family":"Anzillotti","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Milan, Italy"},{"name":"Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20072 Pieve Emanuele, Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesco","family":"La Camera","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0254-3143","authenticated-orcid":false,"given":"Emanuela","family":"Morenghi","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Milan, Italy"},{"name":"Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20072 Pieve Emanuele, Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-2406-6183","authenticated-orcid":false,"given":"Guido","family":"Grappiolo","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8569-0669","authenticated-orcid":false,"given":"Mattia","family":"Loppini","sequence":"additional","affiliation":[{"name":"IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Milan, Italy"},{"name":"Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20072 Pieve Emanuele, Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1455","DOI":"10.2106\/JBJS.17.01617","article-title":"Projected Volume of Primary Total Joint Arthroplasty in the U.S., 2014 to 2030","volume":"100","author":"Sloan","year":"2018","journal-title":"J. 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Today"}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/14\/16\/5620\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:26:40Z","timestamp":1760034400000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/14\/16\/5620"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,8,8]]},"references-count":35,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2025,8]]}},"alternative-id":["jcm14165620"],"URL":"https:\/\/doi.org\/10.3390\/jcm14165620","relation":{},"ISSN":["2077-0383"],"issn-type":[{"type":"electronic","value":"2077-0383"}],"subject":[],"published":{"date-parts":[[2025,8,8]]}}}