{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,12]],"date-time":"2026-09-12T23:44:37Z","timestamp":1789256677771,"version":"build-2803163510"},"reference-count":31,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,7,22]],"date-time":"2025-07-22T00:00:00Z","timestamp":1753142400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Medartis AG"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>The scaphoid is the most commonly fractured carpal bone. Headless compression screws became the gold standard for fixation, but the ideal screw diameter remains debated. This study investigates the relative benefit of using a larger screw diameter to improve stability in typical scaphoid fractures. It also examines the effects of preload and screw length on mechanical behaviour. A finite element (FE) model of a mid-waist scaphoid fracture was created. Screws from Medartis (1.7 mm, 2.2 mm, and 3.0 mm diameter; 23 mm length) were placed along the longitudinal axis. Boundary and loading conditions matched prior studies. Interfragmentary displacement (IFD) and von Mises stress were compared across screw sizes. The effects of screw length and preload were also evaluated. Maximum in-plane IFD was 2.08 mm (1.7 mm screw), 0.53 mm (2.2 mm), and 0.27 mm (3.0 mm). The 1.7 mm screw exceeded the scaphoid\u2019s average ultimate stress (60.51 MPa). Increasing preload reduced IFD, especially above 60 N. Screws longer than 1.5 times the mid-waist diameter offered no added benefit. Larger screws provide better biomechanical fracture stability. However, the gain from 2.2 mm to 3.0 mm is minor, while 1.7 mm screws lack sufficient strength. The 2.2 mm screw offers a good balance of stability and bone preservation, making it the preferred choice.<\/jats:p>","DOI":"10.3390\/bioengineering12080790","type":"journal-article","created":{"date-parts":[[2025,7,22]],"date-time":"2025-07-22T15:00:42Z","timestamp":1753196442000},"page":"790","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Comparative Assessment of the Mechanical Response to Different Screw Dimensions in Scaphoid Fracture Fixation"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2193-7746","authenticated-orcid":false,"given":"Esin","family":"Rothenfluh","sequence":"first","affiliation":[{"name":"Department of Plastic and Hand Surgery, Inselspital, Bern University Hospital, 3010 Bern, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sambhav","family":"Jain","sequence":"additional","affiliation":[{"name":"Department of Plastic and Hand Surgery, Inselspital, Bern University Hospital, 3010 Bern, Switzerland"},{"name":"Laboratory for Movement Biomechanics, Department of Health Sciences and Technology, ETH Z\u00fcrich, 8092 Z\u00fcrich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4060-4098","authenticated-orcid":false,"given":"William R.","family":"Taylor","sequence":"additional","affiliation":[{"name":"Laboratory for Movement Biomechanics, Department of Health Sciences and Technology, ETH Z\u00fcrich, 8092 Z\u00fcrich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3518-3316","authenticated-orcid":false,"given":"Seyyed Hamed","family":"Hosseini Nasab","sequence":"additional","affiliation":[{"name":"Laboratory for Movement Biomechanics, Department of Health Sciences and Technology, ETH Z\u00fcrich, 8092 Z\u00fcrich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"E41","DOI":"10.1097\/TA.0b013e31822458e8","article-title":"Scaphoid fracture epidemiology","volume":"72","author":"Duckworth","year":"2012","journal-title":"J. Trauma Acute Care Surg."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1080\/02844319950159145","article-title":"Epidemiology of scaphoid fractures in Bergen, Norway","volume":"33","author":"Hove","year":"1999","journal-title":"Scand. J. Plast. Reconstr. Surg. Hand Surg."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1177\/1753193419849767","article-title":"The epidemiology of scaphoid fractures in Sweden: A nationwide registry study","volume":"44","author":"Sward","year":"2019","journal-title":"J. Hand Surg. Eur. Vol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1302\/2058-5241.5.190025","article-title":"Acute scaphoid fractures: Guidelines for diagnosis and treatment","volume":"5","author":"Clementson","year":"2020","journal-title":"EFORT Open Rev."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"390","DOI":"10.1016\/S0140-6736(20)30931-4","article-title":"Surgery versus cast immobilisation for adults with a bicortical fracture of the scaphoid waist (SWIFFT): A pragmatic, multicentre, open-label, randomised superiority trial","volume":"396","author":"Dias","year":"2020","journal-title":"Lancet"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"988","DOI":"10.1016\/j.jhsa.2008.04.026","article-title":"Treatment of scaphoid fractures and nonunions","volume":"33","author":"Kawamura","year":"2008","journal-title":"J. Hand Surg. Am."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.hcl.2019.03.002","article-title":"Diagnosis and Management of Acute Scaphoid Fractures","volume":"35","author":"Sabbagh","year":"2019","journal-title":"Hand Clin."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"828","DOI":"10.1302\/0301-620X.73B5.1894676","article-title":"Need the thumb be immobilised in scaphoid fractures? A randomised prospective trial","volume":"73","author":"Clay","year":"1991","journal-title":"J. Bone Jt. Surg. Br."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1097\/01.blo.0000205886.66081.9d","article-title":"Minimally invasive management of scaphoid nonunions","volume":"445","author":"Slade","year":"2006","journal-title":"Clin. Orthop. Relat. Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1007\/s12178-011-9072-0","article-title":"Assessment of scaphoid fracture healing","volume":"4","author":"Hackney","year":"2011","journal-title":"Curr. Rev. Musculoskelet. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1246","DOI":"10.1016\/j.jhsa.2010.05.011","article-title":"Optimal fixation of acute scaphoid fractures: Finite element analysis","volume":"35","author":"Luria","year":"2010","journal-title":"J. Hand Surg. Am."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"72","DOI":"10.2106\/00004623-200301000-00012","article-title":"Central placement of the screw in simulated fractures of the scaphoid waist: A biomechanical study","volume":"85","author":"McCallister","year":"2003","journal-title":"J. Bone Jt. Surg. Am."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"405","DOI":"10.1016\/j.jhsa.2005.09.014","article-title":"Screw fixation of scaphoid fractures: A biomechanical assessment of screw length and screw augmentation","volume":"31","author":"Dodds","year":"2006","journal-title":"J. Hand Surg. Am."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Gareb, B., van Munster, V.D.M., Dijkstra, P.U., Bos, R.R.M., Vissink, A., van Bakelen, N.B., and van Minnen, B. (2022). Reliability and accuracy of the torque applied to osteosynthesis screws by maxillofacial surgeons and residents. Sci. Rep., 12.","DOI":"10.1038\/s41598-022-18687-7"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1177\/17531934231157565","article-title":"The influence of partial union on the mechanical strength of scaphoid fractures: A finite element study","volume":"48","author":"Rothenfluh","year":"2023","journal-title":"J. Hand Surg. Eur. Vol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Oftadeh, R., Perez-Viloria, M., Villa-Camacho, J.C., Vaziri, A., and Nazarian, A. (2015). Biomechanics and mechanobiology of trabecular bone: A review. J. Biomech. Eng., 137.","DOI":"10.1115\/1.4029176"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1016\/S0266-7681(03)00077-9","article-title":"The results of treatment of 734 fresh, simple fractures of the scaphoid","volume":"28","author":"Bohler","year":"2003","journal-title":"J. Hand Surg. Br."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1107","DOI":"10.1016\/j.otsr.2018.07.013","article-title":"Comparison of volar versus dorsal screw fixation for scaphoid waist fractures: A finite element analysis","volume":"104","author":"Acar","year":"2018","journal-title":"Orthop. Traumatol. Surg. Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1055\/s-0039-1685514","article-title":"Impact of Screw Length on Proximal Scaphoid Fracture Biomechanics","volume":"8","author":"Patel","year":"2019","journal-title":"J. Wrist Surg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"458","DOI":"10.1016\/S0363-5023(89)80004-8","article-title":"The effects of various load paths and different loads on the load transfer characteristics of the wrist","volume":"14","author":"Viegas","year":"1989","journal-title":"J. Hand Surg. Am."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Erhart, J., Unger, E., Schefzig, P., Varga, P., Trulson, I., Gormasz, A., Trulson, A., Reschl, M., Hagmann, M., and Vecsei, V. (2016). Rotational Stability of Scaphoid Osteosyntheses: An In Vitro Comparison of Small Fragment Cannulated Screws to Novel Bone Screw Sets. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0156080"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Gruszka, D., Herr, R., Hely, H., Hofmann, P., Klitscher, D., Hofmann, A., and Rommens, P.M. (2016). Impact of Different Screw Designs on Durability of Fracture Fixation: In Vitro Study with Cyclic Loading of Scaphoid Bones. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0145949"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.medengphy.2015.11.006","article-title":"A finite element analysis of two novel screw designs for scaphoid waist fractures","volume":"38","author":"Varga","year":"2016","journal-title":"Med. Eng. Phys."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Gersie, T., Bitter, T., Wolfson, D., Freeman, R., Verdonschot, N., and Janssen, D. (2024). Quantification of long-term nonlinear stress relaxation of bovine trabecular bone. J. Mech. Behav. Biomed. Mater., 152.","DOI":"10.1016\/j.jmbbm.2024.106434"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"24730114211015203","DOI":"10.1177\/24730114211015203","article-title":"Mechanical Effects of Lag Screw Retightening in a Simulated Hindfoot Arthrodesis Model","volume":"6","author":"Rugg","year":"2021","journal-title":"Foot Ankle Orthop."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1005","DOI":"10.1016\/j.jhsa.2007.05.030","article-title":"Anthropometry of the human scaphoid","volume":"32","author":"Heinzelmann","year":"2007","journal-title":"J. Hand Surg. Am."},{"key":"ref_27","first-page":"184","article-title":"Anthropometry of the Human Scaphoid Waist by Three-Dimensional Computed Tomography","volume":"24","author":"Smith","year":"2015","journal-title":"J. Surg. Orthop. Adv."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1016\/j.jhsa.2017.10.005","article-title":"Scaphoid Fracture Fixation in a Nonunion Model: A Biomechanical Study Comparing 3 Types of Fixation","volume":"43","author":"Mandaleson","year":"2018","journal-title":"J. Hand Surg. Am."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1177\/1558944715614889","article-title":"Mechanical Evaluation of Four Internal Fixation Constructs for Scaphoid Fractures","volume":"11","author":"Beutel","year":"2016","journal-title":"Hand"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1515\/bmt-2016-0090","article-title":"Larger screw diameter may not guarantee greater pullout strength for headless screws\u2014A biomechanical study","volume":"62","author":"Lin","year":"2017","journal-title":"Biomed. Tech."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"652","DOI":"10.1016\/j.medengphy.2006.08.005","article-title":"The influence of wire positioning upon the initial stability of scaphoid fractures fixed using Kirschner wires A finite element study","volume":"29","author":"Ezquerro","year":"2007","journal-title":"Med. Eng. Phys."}],"container-title":["Bioengineering"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-5354\/12\/8\/790\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:14:08Z","timestamp":1760033648000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-5354\/12\/8\/790"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,22]]},"references-count":31,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2025,8]]}},"alternative-id":["bioengineering12080790"],"URL":"https:\/\/doi.org\/10.3390\/bioengineering12080790","relation":{},"ISSN":["2306-5354"],"issn-type":[{"value":"2306-5354","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,22]]}}}