Impact of Supraspinatus Muscle Advancement on the Biomechanics of Irreparable Rotator Cuff Tear Repair: A Finite Element Analysis

Sofia Silva Brás

Key information

Authors:

Supervisors:

João Orlando Marques Gameiro Folgado (João Orlando Marques Gameiro Folgado); Carlos Miguel Fernandes Quental (Carlos Quental)

Published in

November 26, 2025

Abstract

Irreparable rotator cuff tears present a significant challenge in orthopedic practice due to the high failure rates associated with traditional repair techniques, often caused by excessive tendon tension, retraction, and poor tissue quality. Muscle advancement techniques, particularly supraspinatus and infraspinatus advancement, have emerged as promising solutions for their ability to restore tendon length and reduce repair tension. However, their biomechanical effects remain insufficiently characterized. While previous studies have focused on the effects of complete detachment and advancement of the supraspinatus muscle, this work investigated how different partial detachment configurations of its origin influence the muscle's mechanical response and its capacity for advancement during repair. A three-dimensional finite element model of the scapula and supraspinatus muscle was developed. The supraspinatus was modeled as an isotropic hyperelastic Neo-Hookean material and the scapula as linear elastic and isotropic. Several detachment configurations were simulated, varying the regions and extent of muscle released from the scapula. A 2 cm displacement was applied to reproduce surgical advancement, and results were evaluated through maximum principal strain and the force required to advance the muscle. Several partial detachment configurations were simulated, differing in both the number of rows detached and their anatomical location (anterior, posterior, central, lateral, or medial). The results showed that partial detachments reduce strain relative to the intact configuration, with posterior and more extensive releases yielding the most favorable biomechanical responses. These findings indicate that strategically designed partial detachments can replicate some benefits of full muscle advancement while preserving native attachment, potentially reducing surgical invasiveness.