Evaluation of Function, Performance, and Preference as Transfemoral Amputees Transition From Mechanical to Microprocessor Control of the Prosthetic Knee

Study design overview. Data-collection sessions follow a period of either mechanical (ie, nonmicroprocessor [NMP]) or microprocessor (MP) control prosthetic knee use. *Time of accommodation varied among subjects.

Daily activity as measured by the mean daily step frequency (left) and mean estimated daily distance (right). Trends were not noted, and differences did not reach significance (P>.05) among sessions.

Performance on level ground as measured by sound- (left) and affected- (right) side step length. A trend of increased affected-side step length in the microprocessor knee (MP, MP2) was noted, but differences did not reach significance (P>.05) among sessions.

Assessment of stair function as measured by the SAI while subjects descend (left) and ascend (right) stairs. A trend of increased score and significant differences (P<.001) were noted between the microprocessor (MP, MP2) and the mechanical control (NMP, NMP2) knees in stair descent.

Assessment of hill function as measured by the HAI (left) and by time (right) as subjects descend the hill. Trends of increased score and decreased time were noted when subjects wore the microprocessor knee. Significant differences (P<.01) were noted in the hill time between the microprocessor (MP, MP2) and the mechanical control (NMP, NMP2) knees.

Assessment of hill function as measured by the sound-side (left) and affected-side (right) step length as subjects descend the hill. A trend of increased sound- and affected-side step length was noted when subjects wore the microprocessor knee. Significant differences (P<.001) were noted in the affected side step between the microprocessor (MP, MP2) and the mechanical control (NMP, NMP2) knees.

Concentration required for ambulation as measured by the divided attention task walking speed (left) and test accuracy (right). A trend of increased walking speed was noted when subjects wore the microprocessor knee, but differences did not reach significance (P>.05) among sessions.

Amputee satisfaction as reported by the first item (“Over the past four weeks, rate how happy you have been with your current prosthesis”) of the PEQ. Significant differences (P<.001) were noted between the microprocessor knee (MP, MP2) and the mechanical control (NMP2) knees.