Journal: Annals of Anatomy

Abbreviation

Ann. Anat.

Publisher

Elsevier

Journal Volumes

ISSN

0940-9602

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2011 - 20142
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Publications 1 - 2 of 2
  • Suitability of Thiel embalmed tendons for biomechanical investigation
    Item type: Journal Article
    Fessel, Gion; Frey, Kevin; Schweizer, Andreas; et al. (2011)
    Annals of Anatomy
    The standard post-mortem storage method for biomechanical testing is freezing. Freezing minimally alters the biomechanical characteristics of tendons but only suspends the process of decay. Chemical fixation arrests decay and overcomes risk of infection, but alters the biomechanical properties of tendons. On the other hand, Thiel preservation has been reported to maintain soft tissue consistency similar to that of living tissue. The current study investigates the effects of Thiel embalming on human digitorum profundus tendons (FDP) from fresh-frozen and Thiel embalmed cadavers. Cross-sectional area was measured at pre-load, samples were preconditioned and then ramped at a constant strain-rate to failure. Thiel preserved tendons had statistically lower failure stress with median of 38 MPa compared to fresh frozen samples with median of 60 MPa (p-value = 0.048) and trended to a decreased tangential modulus. To overcome limited donor number and masking factors of age, gender, and time embalmed, we also performed experiments in rat tail tendon fascicle. Similar quasi-static ramp to failure tests were performed with control and Thiel treated sample pairs. Similar differences were observed to those found as in human FDP, however these trends were statistically significant. In both tendons, Thiel preserved samples demonstrated altered failure characteristics, indicating a different collagen fiber/collagen network failure mechanism most likely due to partial denaturing by boric acid in Thiel solution. In conclusion, Thiel embalmed tendons did not faithfully represent the biomechanical characteristics of fresh frozen tendons.
  • Changes in length of the plantar aponeurosis during the stance phase of gait – An in vivo dynamic fluoroscopic study
    Item type: Journal Article
    Fessel, Gion; Jacob, Hilaire A.C.; Wyss, Christian; et al. (2014)
    Annals of Anatomy
    In locomotion, ligaments and muscles have been recognized to support the arch of the foot. However, it remains unclear to what extent the passive and active structures of the lower extremity support the longitudinal arch of the foot during walking. In this study, the mechanical function of the plantar aponeurosis (PA) is investigated by elongation measurements in vivo during the stance phase of gait, in combination with measurements of the mechanical properties of the PA in vitro. Fluoroscopy was used to measure the dynamic changes in PA length and the angular motion of the metatarsophalangeal joint of the first ray, measured during the stance phase (StPh) in 11 feet. Simultaneously, ground forces were measured. Additionally, four cadaver feet delivered topographic information relating to the PA, and three autopsy specimens of PA served to determine the in vitro mechanical properties of PA. The present study revealed a non-significant peak average PA shortening of 0.48% at about 32.5% StPh, followed by a significant average peak elongation of 3.6% at 77.5% StPh. This average peak elongation of 3.6% corresponds to a force of 292 N, as estimated by mechanical testing of the autopsy PA specimens. Considering the maximum peak elongation measured in one volunteer of 4.8% at 76% StPh, a peak PA load of 488 N might be expected. Hence, with an average body weight of 751 N, as allocated to the 11 investigated feet, this maximum peak force would correspond to about 0.65 × body weight. As far as we are aware, this is the first report on a dynamic fluoroscopic study of the PA in gait with an appreciable number of feet (11 feet). In conclusion, muscles contribute to support of the longitudinal arch of the foot and can possibly relax the PA during gait. The ‘windlass effect’ for support of the arch in this context is therefore questionable.
Publications 1 - 2 of 2