Musculoskeletal simulation of elbow stability for common injury patterns

Abstract

Elbow stability is derived from a combination of muscular, ligamentous, and bony structures. After an elbow trauma the stability of the joint is an important decision criterion for the subsequent treatment. The decision regarding nonoperative/operative care depends mostly on subjective assessments of medical experts. Therefore, the aim of this study is to use musculoskeletal simulations as an objective assessment tool to investigate the extent to which failure of different stabilizers affects the elbow stability and how these observations correspond to the assessment from clinical practice. A musculoskeletal elbow simulation model was developed for this aim. To investigate the stability of the elbow, varus/valgus moments were applied under 0°, 45°, and 90° flexion while the respective cubital angle was analyzed. This was performed for nine different injury scenarios, which were also evaluated for stability by clinical experts. With the results, it can be determined by which injury pattern and under which flexion angle the elbow stability is impaired regarding varus/valgus moments. The scenario with a complete failure of the medial and lateral ligaments and a fracture of the radial head was identified as having the greatest instability. The study presented a numerical determination of elbow stability against varus/valgus moments regarding clinical injury patterns, as well as a comparison of the numerical outcome with experience gained in clinical practice. The numerical predictions agree well with the assessments of the clinical specialists. Thus, the results from musculoskeletal simulation can make an important contribution to a more objective assessment of the elbow stability.

Direct intraoperative measurement of isometric contractile properties in living human muscle

“…Given these experimental results, it has become accepted practice to predict isometric muscles properties when direct measurements cannot or have not been made. In humans, skeletal muscle architectural principles have been generalized to explain healthy and pathological movement (Arnold et al., 2010; Binder‐Markey et al., 2019; Halilaj et al., 2018; Melzner et al., 2022; Sartori et al., 2017), guide surgical procedures (Bolsterlee et al., 2013; Delp et al., 1990; Nichols et al., 2016), understand muscle design (Blemker & Delp, 2006; Hosseini Nasab et al., 2022; Kapelner et al., 2020; Tennler et al., 2022) and predict performance (Crotin et al., 2022; Heiderscheit et al., 2022; Sinclair et al., 2022). Despite the scores of predictions made for a number of cases, direct validation is rare, and it is thus critical that we pursue validation of the major assumptions made and used in these human models.…”