Iran Medical Council Journal of Iranian Medical Council 2645-338X 9 4 2026 08 01 A Mathematical Model to Predict the Angle of Z-plasty and Rotation with Trigonometric Relationships 908 913 251633 http://dx.doi.org/10.18502/jimc.v9i4.22459 EN Fardin Rahmanpoor Innovative Medical Research Center, Islamic Azad University, Mashhad, Iran Department of Mathematics, Yazd University, Yazd, Iran 0009-0006-9558-5153 Tooraj Zandbaf Department of General Surgery, Islamic Azad University, Mashhad, Iran 0000-0002-4882-5058 Ali Ahmadabadi Surgical Oncology Research Centre, Mashhad University of Medical Sciences, Mashad, Iran 0000-0002-3623-6192 Journal Article 2025 05 19 <strong>Background:</strong> Burns contractions restrict limb movement. Z-plasty is a widely used technique for repairing contractures resulting from burns. <br><strong>Methods:</strong> Equations were derived utilizing trigonometric relationships that enable surgeons to estimate the angle and rotation of the Z-plasty based on the degree of lengthening required for the contracted area. <br><strong>Results:</strong> This study introduces a mathematical model designed to assist surgeons in selecting a Z-plasty with the appropriate angle and rotation. Numerical results were presented for various lengths of contracture in non-classical Z-plasties.<br><strong>Conclusion:</strong> This model aims to enhance surgical precision and facilitate the development of standardized procedures. https://www.jimc.ir/article_251633_424ec041440091493d3d872150ac83ee.pdf