Surgical Simulations Based on Limited Quantitative Data: Understanding How Musculoskeletal Models Can Be Used to Predict Moment Arms and Guide Experimental Design

Abstract

The utility of biomechanical models and simulations to examine clinical problems is currently limited by the need for extensive amounts of experimental data describing how a given procedure or disease affects the musculoskeletal system. Methods capable of predicting how individual biomechanical parameters are altered by surgery are necessary for the efficient development of surgical simulations. In this study, we evaluate to what extent models based on limited amounts of quantitative data can be used to predict how surgery influences muscle moment arms, a critical parameter that defines how muscle force is transformed into joint torque. We specifically examine proximal row carpectomy and scaphoid-excision four-corner fusion, two common surgeries to treat wrist osteoarthritis. Using models of these surgeries, which are based on limited data and many assumptions, we perform simulations to formulate a hypothesis regarding how these wrist surgeries influence muscle moment arms. Importantly, the hypothesis is based on analysis of only the primary wrist muscles. We then test the simulation-based hypothesis using a cadaveric experiment that measures moment arms of both the primary wrist and extrinsic thumb muscles. The measured moment arms of the primary wrist muscles are used to verify the hypothesis, while those of the extrinsic thumb muscles are used as cross-validation to test whether the hypothesis is generalizable. The moment arms estimated by the models and measured in the cadaveric experiment both indicate that a critical difference between the surgeries is how they alter radial-ulnar deviation versus flexion-extension moment arms at the wrist. Thus, our results demonstrate that models based on limited quantitative data can provide novel insights. This work also highlights that synergistically utilizing simulation and experimental methods can aid the design of experiments and make it possible to test the predictive limits of current computer simulation techniques.

Connecting the wrist to the hand: A simulation study exploring changes in thumb-tip endpoint force following wrist surgery

“…Despite this limitation, our results are important because they identify novel, biomechanically-driven hypotheses to be experimentally tested. We have previously demonstrated that hypotheses derived from theoretical simulations and limited quantitative data improved the design and analysis of biomechanical experiments (Nichols et al 2016). Such experiments can also simultaneously address issues associated with external validation of our models.…”

“…For example, the nonimpaired thumb model (excluding the wrist) was validated by replicating cadaveric and in vivo data (see Wohlman and Murray 2013). The endpoint forces simulated with the SE4CF and PRC models have not been evaluated against similar data, despite being based on experimental data (Blankenhorn et al 2007; Nichols et al 2015; Nichols et al 2016; Nichols et al 2017). While many studies summarize clinical outcomes of these surgeries, studies that provide the scope and quantitative detail needed to validate our biomechanicalsimulationsdonotexist.Experimentalvalidationisalsoneededtoinformexpansion of the models to include finger kinematics, which were excluded from this study, as well as extrinsic finger muscles, which we represented as reserve torques.…”

“…Additionally, in both models, the muscle lines of action of the primary wrist and extrinsic thumb muscles were adjusted to replicate experimentally measured wrist flexion-extension and radial-ulnar deviation moment arms following SE4CF and PRC (Nichols et al. 2015; Nichols et al 2016). Muscle force-generating parameters associated with the Hill-type model were equivalent across the nonimpaired, SE4CF, and PRC models.…”

“…To test this hypothesis, we leverage available biomechanical data characterizing the wrist surgeries (Blankenhorn et al. 2007; Nichols et al 2015; Nichols et al 2016; Nichols et al 2017) and computational advances in biomechanical simulation of force development at the thumb (Valero-Cuevas et al 2003; Goehler and Murray 2010; Wohlman and Murray 2013) to develop dynamic musculoskeletal simulations of lateral pinch force that integrate the wrist and thumb. We then utilize these simulations to specifically examine how having a nonimpaired versus a surgically-altered wrist influences joint torques, muscle force transmission, and muscle control strategies during lateral pinch.…”

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.…”