femoral offset AMMRV 1.5


I have a model I have been working on where I have trying to modify the femoral offset. I was told to upload it onto here as I was having some issues. I have incorporated some code to vary the femoral offset but once I try to process the code I get the same values for different offsets. This is with AMMRV 1.5. I just wanted to know what the problem was. Furthermore, I would like to vary the femoral offset without causing any scaling of the muscles and would like them to stretch when the offset is changed. This would require some form of calibration but I am unsure of how to incorporate this into the model.

Hi Ammar,

look at the screenshots below for what happens when you change your chosen parameter (on the left the standard model, on the right a changed y-value):

I don’t understand what exactly you want to achieve but would it be impracticable to just change the scaling of the femur? Or is your goal to move the COR of the hip joint?


Thanks Patrick

The COR would be something that I would be interested in changing in the future. I am trying to change the femoral offset in order to simulate THA where a surgeon places a artificial prosthesis. Placing the prosthesis is subjective so there can be variations in the offset which can lead to a leg length difference. I want to simulate a leg length difference.


Hi Ammar,

You will need to do the following:

[li]change the location of the hip joint node on on the Thigh segment[/li][li]if you run the witht the three element muscles, then run the calibration with the model using the old hip joint location, and save the modified values. Then load the model with the new location and reload the calibrated muscle parameters. Then run the model.[/li][/ol]Best regards