Prosthetic knee joint measurement system including energy harvesting and method therefor

An orthopedic measurement system comprising:

• a piezo-electric element coupled to a patella;
• a storage device coupled to the piezo-electric element where a knee joint is configured to apply a non-constant force to the piezo-electric element as a knee joint moves through a range of motion and where the storage device is configured to store energy generated by the piezo-electric element;
• and
• electronic circuitry coupled to the storage device.

A method of providing energy to electronic circuitry comprising the steps of:

• moving a knee joint through a range of motion where an energy-harvesting device on a patella couples to a region between condyles of a femoral prosthetic component whereby a variable force is generated on the energy-harvesting device as the knee joint is flexed;
• generating energy as the variable force is applied to the energy-harvesting device;
• charging a storage device with the energy generated by the energy-harvesting device;
• powering electronic circuitry in a prosthetic component with energy harvested from the energy-harvesting device.