Alexander Nolte, a German student at Trauma Center Murnau, Germany, and Paracelsus Private Medical University Salzburg, Austria, recently completed his Diploma thesis Analysis of the muscle and joint forces in the shoulder joint using the AnyBody simulation model.
modeled shoulder abduction, shoulder flexion, and the lifting of a coffee pot with and without weight.
The results of simulation for the abduction and "lifting a coffee pot" were similar to measured joint reaction forces obtained by the Bergmann's endoprosthesis study.
In contrast, the simulation of the flexion indicated much larger forces than Bergmann measured and a rotated force vector pointing into the socket of the joint.
speculates that the cause for this discrepancy between model and experiment might be due to some muscles not functioning in the patient after surgery or that the motion in the collarbone-scapula and sternum-collarbone joints were not taken into account in the simulation.