An Investigation of Functional Improvements in the RHEO KNEE Compared to Hydraulic Microprocessor Controlled Knees (MPKs)

The aim of this study was to evaluate the mobility, perceived safety and functioning of unilateral transfemoral (TF) amputees using the Rheo Knee XC compared to their existing prosthetic knee (RHEO KNEE II, III or Genium, X2 or X3) after 3 weeks of use. The primary objective of the study was to determine/investigate whether unilateral (TF) amputees can apply and benefit from the stair ascent function of the Rheo Knee XC and compare the stair ascent function and automatic cycling detection of the Rheo Knee XC to hydraulic microprocessor controlled knees (MPK-HY). The testing was conducted in a non-blinded, multicenter, prospective within subject comparison, with a subgroup analysis with Magneto-rheologic microprocessor controlled knees (MPK-MR) subgroup and MPK-HY subgroup comparing to the Rheo knee XC. A convenience sample of 15 transfemoral amputee users was recruited at 4 study sites. Inclusion criteria: * Cognitive ability to understand all instructions and questionnaires in the study; * Unilateral knee-disarticulated or transfemoral users fitted to Rheo Knee II,III or Genium * Willing and able to participate in the study and follow the protocol * Confident prosthetic users for more than 3 months * Older than 18 years Exclusion Criteria * Patients with the following characteristics are not eligible for study entry: * 50Kg> body weight > 136Kg * Users with cognitive impairment * Users not understanding the function of the knee * Users not able to charge the battery Testing was conducted between June and August 2015 in four US locations. Participants visited the study location twice, for approximately 3 hours per visit. First time for the baseline measure and initial fitting and secondly after 3 weeks of accommodation on the Rheo knee XC, performing the same measures as for the baseline. Measures included 6 minute walk test with Borg scale CR pre and post, L-test, stair assessment index, stair and bicycle evaluation and Prosthesis evaluation questionnaire mobility section (PEQ MS12/5) For statistics repeated measures analysis of variance (ANOVA) comparing baseline to 3 week follow up were performed.