Estimating active forearm pronation-supination motion by means of FE modelling

Active range of motion (ROM) of the forearm is important for completing daily life activities (ADL). Such motion could be compromised as a result of a poorly healed fracture. Although numerical models are often used to aide medical treatment, most of them are static. In addition, there is no previous model nor methodology related to forearm and its motion. In this work, a methodology to create finite element models that can evaluate active ROM is developed and validated. The biomechanical behaviour of the ligamentous structures, as a whole, was compared with data available from previous studies. The active ROM was validated against experimental measurements of active ROM. The ROM predicted with this methodology was 72º in pronation and 83º in supination; these values are within 5º from the standardised values for human ROM. In addition, this work supports the hypothesis that the muscles are limiting structures of the ROM, such task was always attributed to ligamentous structures. Nevertheless, in active ROM, muscle contraction and extension delimited the arc of motion. In summary, this work provides a methodology, mechanical properties of ligamentous structures, types of constrains and kinematic assumptions to produce a biomechanically sound model of the forearm which can be used for further study of forearm fractures.