Biomechanical Thresholds for Failure: Why Cleveland Zone and Reduction Quality Matter More Than TAD in PFN

Biomechanical Thresholds for Failure: Why Cleveland Zone and Reduction Quality Matter More Than TAD in PFN | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Biomechanical Thresholds for Failure: Why Cleveland Zone and Reduction Quality Matter More Than TAD in PFN Hasip Turan SIMSEK, Elyesa ERGEN, Yavuzhan ALTIN, Abtullah MILCAN This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9003758/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Cut-out remains a major mechanical complication following proximal femoral nailing. This study aimed to evaluate radiographic predictors of cut-out, focusing on reduction quality, screw position within the femoral head, and tip–apex distance (TAD). Methods Seventy-one patients treated with proximal femoral nailing were retrospectively analyzed. Cut-out occurred in 10 patients (14.1%). Reduction quality (Fogagnolo classification), Cleveland zone of screw placement, collodiaphyseal angle (CDA), and TAD were assessed. Univariate analyses were performed, followed by restricted multivariable logistic regression due to limited event number. A trend analysis was conducted for reduction quality. Absolute risk differences were calculated for screw position categories. Receiver operating characteristic (ROC) analysis evaluated the discriminative performance of continuous TAD. Results Cut-out was significantly associated with Cleveland zone placement (p = 0.011), with no failures occurring in favorable zones (5 or 8). Screw placement outside these zones was associated with an absolute 21.7% increase in cut-out risk. A significant linear trend was observed between worsening reduction quality and increasing cut-out risk (OR per category increase 2.56; 95% CI 1.08–6.05; p = 0.032). CDA ≤ 120° was associated with higher failure rates (p = 0.022). In multivariable analysis (poor reduction and TAD > 25 mm), no independent predictor reached statistical significance, likely due to the limited number of events. Continuous TAD demonstrated limited discriminative ability (AUC = 0.63). Inter-observer reliability was high for both TAD measurement ( r = 0.985). Interobserver agreement for Cleveland zone classification was moderate to substantial ( κ range 0.58–0.61). Clinically, mechanical failure resulted in poor functional outcomes, with mean Harris Hip Scores dropping significantly from 72.6 in successful cases to 30.0 in the failure group. Conclusion Cut-out appears to be more strongly influenced by construct-related biomechanical factors—particularly reduction quality and screw position within the femoral head—than by TAD threshold alone. These findings suggest that precise screw placement and restoration of alignment may act as biomechanical thresholds for preventing mechanical failure. intertrochanteric fractures PFN cut-out mechanical failure tip–apex distance reduction quality Cleveland classification Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryTable3.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9003758","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":607611048,"identity":"4a18e9fe-c12f-44eb-a141-394c4905b5f5","order_by":0,"name":"Hasip Turan SIMSEK","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyklEQVRIiWNgGAWjYDADCfYGIGlgQVglD1wLzwGQFglStEgkgCnCWuwlch9+LvizzV5y5vOrG34USDDwt3cn4LdFIt1Yembb7cTZ0jllN3uADpM4c3YDAS1pDNK8DbcT5KRz0m7wALUYSOQS1ML8m+fPbXs5yTNpN/8QqYVNmoftNuNsCfZjt4mz5cwzNmteoF9m9uSw3ZYxkOAh6Bf29jTm2yCHSRw//uzmmz82cvztvfi1IFtoACaJVQ628AEpqkfBKBgFo2AEAQAZMUDfxy8tLAAAAABJRU5ErkJggg==","orcid":"","institution":"Mersin City Training and Research Hospital","correspondingAuthor":true,"prefix":"","firstName":"Hasip","middleName":"Turan","lastName":"SIMSEK","suffix":""},{"id":607611049,"identity":"4ff3f298-39eb-4125-a406-37e062cb114a","order_by":1,"name":"Elyesa ERGEN","email":"","orcid":"","institution":"Mersin University","correspondingAuthor":false,"prefix":"","firstName":"Elyesa","middleName":"","lastName":"ERGEN","suffix":""},{"id":607611050,"identity":"9596a059-5406-4955-b79c-c67a59abbff5","order_by":2,"name":"Yavuzhan ALTIN","email":"","orcid":"","institution":"Gaziantep Dr. Ersin Arslan Training and Research Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yavuzhan","middleName":"","lastName":"ALTIN","suffix":""},{"id":607611051,"identity":"2eefcb98-e4ce-49b0-a2f1-51aca877129d","order_by":3,"name":"Abtullah MILCAN","email":"","orcid":"","institution":"Mersin University","correspondingAuthor":false,"prefix":"","firstName":"Abtullah","middleName":"","lastName":"MILCAN","suffix":""}],"badges":[],"createdAt":"2026-03-01 20:38:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9003758/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9003758/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107792362,"identity":"10dd9330-c9b2-46ac-8db4-d1a399830782","added_by":"auto","created_at":"2026-04-25 13:55:23","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":739584,"visible":true,"origin":"","legend":"","description":"","filename":"1.MANUSCRIPT.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9003758/v1_covered_da195260-e370-4a1d-a80b-f4775168004c.pdf"},{"id":104967731,"identity":"96323c61-3d15-46df-be9f-bc26bd2a76e8","added_by":"auto","created_at":"2026-03-19 10:11:29","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":8213,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryTable3.docx","url":"https://assets-eu.researchsquare.com/files/rs-9003758/v1/3373d6fa1ce8f301f43a4047.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Biomechanical Thresholds for Failure: Why Cleveland Zone and Reduction Quality Matter More Than TAD in PFN","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"intertrochanteric fractures, PFN, cut-out, mechanical failure, tip–apex distance, reduction quality, Cleveland classification","lastPublishedDoi":"10.21203/rs.3.rs-9003758/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9003758/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eCut-out remains a major mechanical complication following proximal femoral nailing. This study aimed to evaluate radiographic predictors of cut-out, focusing on reduction quality, screw position within the femoral head, and tip\u0026ndash;apex distance (TAD).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eSeventy-one patients treated with proximal femoral nailing were retrospectively analyzed. Cut-out occurred in 10 patients (14.1%). Reduction quality (Fogagnolo classification), Cleveland zone of screw placement, collodiaphyseal angle (CDA), and TAD were assessed. Univariate analyses were performed, followed by restricted multivariable logistic regression due to limited event number. A trend analysis was conducted for reduction quality. Absolute risk differences were calculated for screw position categories. Receiver operating characteristic (ROC) analysis evaluated the discriminative performance of continuous TAD.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eCut-out was significantly associated with Cleveland zone placement (p\u0026thinsp;=\u0026thinsp;0.011), with no failures occurring in favorable zones (5 or 8). Screw placement outside these zones was associated with an absolute 21.7% increase in cut-out risk. A significant linear trend was observed between worsening reduction quality and increasing cut-out risk (OR per category increase 2.56; 95% CI 1.08\u0026ndash;6.05; p\u0026thinsp;=\u0026thinsp;0.032). CDA\u0026thinsp;\u0026le;\u0026thinsp;120\u0026deg; was associated with higher failure rates (p\u0026thinsp;=\u0026thinsp;0.022). In multivariable analysis (poor reduction and TAD\u0026thinsp;\u0026gt;\u0026thinsp;25 mm), no independent predictor reached statistical significance, likely due to the limited number of events. Continuous TAD demonstrated limited discriminative ability (AUC\u0026thinsp;=\u0026thinsp;0.63). Inter-observer reliability was high for both TAD measurement (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.985). Interobserver agreement for Cleveland zone classification was moderate to substantial (\u003cem\u003eκ\u003c/em\u003e range 0.58\u0026ndash;0.61). Clinically, mechanical failure resulted in poor functional outcomes, with mean Harris Hip Scores dropping significantly from 72.6 in successful cases to 30.0 in the failure group.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eCut-out appears to be more strongly influenced by construct-related biomechanical factors\u0026mdash;particularly reduction quality and screw position within the femoral head\u0026mdash;than by TAD threshold alone. These findings suggest that precise screw placement and restoration of alignment may act as biomechanical thresholds for preventing mechanical failure.\u003c/p\u003e","manuscriptTitle":"Biomechanical Thresholds for Failure: Why Cleveland Zone and Reduction Quality Matter More Than TAD in PFN","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-19 10:09:11","doi":"10.21203/rs.3.rs-9003758/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6ea2f386-4790-4474-b9c8-2034d8e2cad1","owner":[],"postedDate":"March 19th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-12T12:44:39+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-19 10:09:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9003758","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9003758","identity":"rs-9003758","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}