Colloquia

Summary

Reboocon Bionics B.V. has developed a new lightweight powered knee prosthesis, referred to as the IntelLeg Knee (ILK). This knee prosthesis is lightweight (2.4 kg including battery) and is actuated using a spindle mechanism. It is expected that transfemoral amputees may benefit from the ILK compared to their (non-powered) daily use prosthesis. To find out the possible benefits of the ILK a clinical study has been carried out, and a new clinical study has been prepared.

The first part of the research was dedicated to analysing one of the activities performed in the first clinical study, being stair negotiation.  The goal was to investigate whether transfemoral amputees (TFAs) benefit from an actively powered prosthesis during Step-over-Step (SOS) stair negotiation, compared to their DUP. With a SOS strategy a person alternates between the legs for each step, which is the most common strategy for healthy persons. Not all TFAs are able to achieve this and often instead use a Step-to (ST) strategy in which steps are negotiated step by step, placing the healthy leg first and then the prosthetic leg on the same step. For stair ascent, subjects already using a SOS strategy achieved kinematics closer to that of healthy subjects using the ILK. Subjects normally using a ST strategy were able to ascent SOS, although they were outperformed by the SOS group. For stair descent no statistically relevant difference were found in any of the metric studied.

The second part of the research was dedicated to preparing a new clinical study focusing on musculoskeletal simulations. With these simulations joint kinematics, kinetics can be obtained and induced acceleration analyses can be executed. With induced acceleration analyses the contribution of individual muscles and the prosthesis to the body center of mass trajectory can be found. This is useful for determining compensatory gait movements as well as finding out whether the prosthesis can replicate the function of the missing muscles in amputees. A full research file has been constructed consisting of a research protocol, among other documents. A single healthy case study has been carried out to test the protocol on a healthy subject wearing the ILK prior to the research. A musculoskeletal model was made in OpenSim and kinematics, kinetics, muscle forces and induced accelerations were calculated with the experimental data as input. It was possible to run all the simulations, although part of the results was incorrect. The case study shows potential for using musculoskeletal modelling based on the available equipment, although more work should be put in improving the modelling to find feasible results.