Extramuscular myofascial force transmission alters substantially the acute effects of surgical aponeurotomy: assessment by finite element modeling

Abstract

Effects of extramuscular myofascial force transmission on the acute effects of aponeurotomy were studied using finite element modeling and implications of such effects on surgery were discussed. Aponeurotomized EDL muscle of the rat was modeled in two conditions: (1) fully isolated (2) with intact extramuscular connections. The specific goal was to assess the alterations in muscle length-force characteristics in relation to sarcomere length distributions and to investigate how the mechanical mechanism of the intervention is affected if the muscle is not isolated. Major effects of extramuscular myofascial force transmission were shown on muscle length-force characteristics. In contrast to the identical proximal and distal forces of the aponeurotomized isolated muscle, substantial proximo-distal force differences were shown for aponeurotomized muscle with extramuscular connections (for all muscle lengths F dist > F prox after distal muscle lengthening). Proximal optimal length did not change whereas distal optimal length was lower (by 0.5 mm). The optimal forces of the aponeurotomized muscle with extramuscular connections exerted at both proximal and distal tendons were lower than that of isolated muscle (by 15 and 7%, respectively). The length of

Tendon and fascial structure contributions to knee muscle excursions and knee joint displacement

“…However, the fascial structure relationships with the neighbouring structures influence force transmission, and consequently, tendon transfer result (Smeulders and Kreulen, 2007;Yucesoy et al, 2007). Our results quantitatively support this theory on G and ST tendons.…”

Epimuscular Myofascial Force Transmission Implies Novel Principles for Muscular Mechanics

“…Note that the proximo-distal force differences are indicative of differential mechanical effects at the muscle's origin and insertion site. For poly-articular muscles, this has special functional consequences because such differential effects manifest themselves differently at the joints spanned by the target muscle (22). For that reason, when attempting to correct a functional problem at a distal joint, the surgery is likely to alter the mechanics at the proximal joint, as well.…”

“…The increased excursion can primarily be explained by an increase in sarcomere length heterogeneity predominantly in muscle fibers located proximal to the intervention, whereas the muscle weakening is primarily caused by a zone of very short sarcomeres in fibers distal to the intervention (21). Because of epimuscular myofascial force transmission, the acute effects of surgical intervention were not unique but were dependent on some associated mechanical conditions (20,22). Such increased understanding of the effects of aponeurotomies allowed us to optimize the location of intervention to maximize the desired outcomes (23).…”

A novel method of studying fascicle architecture in relaxed and contracted muscles

“…Increasingly, the finite-element mesh method is used to describe muscle behaviour. In this method, individual elements representing the contractile units are interlinked by mathematical equations (e.g., Vankan et al, 1998;Johansson et al, 2000;Meier and Blickhan, 2000;Jenkyn et al, 2002;Oomens et al, 2003;Blemker et al, 2006;Böl and Reese, 2008;Hedenstierna et al, 2008;Yücesoy et al, 2008;Tang et al, 2009). To verify such models, comparison with natural muscles are essential and the more accurate the input parameters for these muscle models, the more precise will be the predicted behaviour and thus the simulated motion (van der Linden et al, 1998).…”