Knee valgus, endo/exo-rotation

[Finn Frielink]

Knee valgus, endo, exo-rotation and head movements do not seem to be captured completely with the model used in Opencap. Will this be added in a newer version? I saw in this topic viewtopicPhpbb.php?f=2385&t=14986&p=0&s ... 3e0205c85f, that you could add new DoF to the model captured with Opencap in Opensim to be able to calculate knee valgus. Is this also possible for the other movements and is there an online tutorial for this?

[Antoine Falisse]

Hi Finn,

We are not planning to update the lower-extremity model in the near future. However, as you mentioned, you could reprocess your data locally with a more expressive model (eg, a model with more degrees of freedom for the knee joint).

The OpenCap source code is posted here: https://github.com/stanfordnmbl/opencap-core
The model we are using is here: https://github.com/stanfordnmbl/opencap ... dHand.osim
And here is an example of how to reprocess data locally: https://github.com/stanfordnmbl/opencap ... essions.py

FYI there is no neck joint in the model, the head is fixed to the torso. This is why you don't see any head movement.

Best,
Antoine

[Ben Senderling]

Knee adduction moments are mentioned in the results of the pre-print article. But the default model in the source code only has a 1 dof knee joint. Is there a reason for that?

[Antoine Falisse]

Hi, you can compute the knee adduction moment using a joint reaction analysis of your simulation results. FYI the code we use to do that is here: https://github.com/stanfordnmbl/opencap ... ing.py#L25

[Bernhard Faerber]

Hi,

what are the steps necessary prior to running the script for estimating KAM?
How does one control which set of data the script is working with?
Can this be done using data dervived from a model other than the base version?

Thanks for any feedback!

Best

Bernhard

[Scott Uhlrich]

The KAM is computed using joint reaction analysis after the simulation. See code antoine posted above. If you are using a different model (eg with a knee adduction dof), you will need to change some things in the simulation.