This subject was a 25 year old female. She had her amputation 3 yr prior as a result of traumatic injury then had a surgical revision 2 yr later to remove excessive redundant soft tissue. Her residual limb was 14 cm in length and was fleshy and bulbous with adherent tissue on the distal tibia. She had a history of inflamed fungus from gel liner use. She was 58 kg in mass and 160 cm in height, and was a very active K-4 level ambulator, using her prosthesis for 16 h/day. She was a marathon racer and triathlete and underwent much residual limb volume reduction during long runs. Otherwise, her limb volume was stable. She regularly used a PTB endoskeletal prosthesis with a gel liner and lock-and-pin suspension, and Renegade Ultralite Foot (Freedom Innovations). During high activity she used an Iceflex endurance sleeve (Ossur) for auxiliary suspension. She was fitted with a new socket equipped with an electronic elevated vacuum system (e-Pulse, Otto Bock), with a Seattle Foot (TrueLife) by her regular prosthetist for this investigation but did not feel comfortable wearing it regularly because of concern of falling while at her waitressing job. Thus she used the elevated vacuum system intermittently. She was tested with her regular prosthesis approximately 10 wk prior to testing with the elevated vacuum system.
This subject was 34 yr of age and had his limb amputation as a result of traumatic injury 3 yr prior. His residual limb was 19 cm in length and was bulbous with redundant soft tissue and a prominent distal tibia. His residual limb had much hair, and was very sensitive to pain. He was 102 kg in mass, 188 cm in height, and a K-3 level ambulator. He wore his prosthesis for approximately 15 h/day. He regularly used a PTB endoskeletal prosthesis with a gel liner and lock-and-pin suspension, and a dynamic response foot (Freedom Innovations). During moderate or high physical activity, he added socks to accommodate residual limb volume reduction. He was tested first using his regular prosthesis. Then for this investigation he was fitted by his regular prosthetist with a new socket equipped with an electronic elevated vacuum system (e-Pulse, Otto Bock) with a Seattle LightFoot (TrueLife). He used that system exclusively for 3 wk prior to bioimpedance testing.
For Cases #5 and #6 (subject descriptions above), as well as Case #7 (described below), for each subject we compared results using an elevated vacuum socket to results using a lock-and-pin socket (different socket). The tests were conducted on different days. Data collection sessions for each subject were at approximately the same time of day for Cases #5 and #6 but were at a different time of day for Case #7 (TABLE 2, column 1). Vacuum settings on the units for Cases #5 and #6 were the 3-setting and 4-setting, respectively.