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Tendon biomechanics

Figure 1: A) and B) Experimental set-up in a material testing machine for evaluation of a speckle tracking algorithm. A) PVA-phantom and human allograft. B) Figure B: Image acquisition of the flexor digitorium tendon in a porcine foot. Figure C: Data collection on a treadmill in the AFO study.

Description (background and methods)

There are several aspects with limited knowledge when it comes to the treatment of Achilles tendon ruptures. For instance the effects on the biomechanical properties of surgically repaired Achilles tendons, and in the treatment of Achilles tendon ruptures ankle foot orthosis (AFO) of different designs are used but their effects on the tendon have not been thoroughly studied.

The studies within this project are collaboration between KTH, The Swedish School of Sport and Health Sciences (GIH) and CLINTEC at the Karolinska Institutet (KI). Our main part is to develop an ultrasound based speckle tracking algorithm for the quantification of displacement and strain in the Achilles tendon, develop phantoms and testing procedures for the evaluation of the method.

A study aiming to evaluate different shoe designs concerning the biomechanical effects on the lower leg during running has recently been started.

(Preliminary) results and publications

In the first study we evaluated a commercial speckle tracking algorithm and found, when used on the Achilles tendon, that the errors in peak strain showed high variability and that the errors were large in relation to strain levels previously described in the Achilles tendon.
The study can be found here: Acta Radiologica 2016, Vol. 57(10) 1223–1229, dx.doi.org/10.1177/0284185115626471

In the second study we concluded that uninjured Achilles tendons display a non-uniform displacement pattern thought to reflect gliding between fascicles, and that this pattern was altered after surgical repair of the tendon which indicates that fascicle sliding is impaired. This could affect the force transmission and tendon elasticity increasing the risk of re-rupture.
The study can be found here: Knee Surg Sports Traumatol Arthrosc (2017) 25:1857–1865, dx.doi.org/10.1007/s00167-016-4394-5

A third article will be submitted during 2018. The main goal of that study was to, in three different AFO types, quantify the biomechanical effects of on the Achilles tendon.

Collaborations

  • Åsa Fröberg, asa.froberg@ki.se
  • Anton Arndt, toni.arndt@gih.se

Thesis projects

  • Analys av muskelaktivitet i underbenet vid gång: En studie på tre olika fotledsortoser

Contact person

Mattias Mårtensson
Mattias Mårtensson
researcher +4687904872
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DIVISION OF BIOMEDICAL IMAGING
Matilda Larsson
Matilda Larsson
professor, head of divison +4687904823
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DIVISION OF BIOMEDICAL IMAGING

Contributors

  • Simon Söderlund, bachelor thesis project
  • Didrik Nimander, bachelor thesis project
  • Matilda Olsson, master thesis project (ongoing)