Below-knee amputee gait in stair ambulation. A comparison of stride characteristics using five different prosthetic feet.

The purpose of this study was to compare the stride characteristics provided by four of the new dynamic elastic response prosthetic feet and the SACH foot to determine if any of them provided an increased performance during stair ambulation. Ten traumatic below-knee amputees were studied; each of them tested all five prosthetic feet (Flex-Foot, Carbon Copy II, Seattle, Quantum, and SACH). Compression closing footswitches were used to calculate stride characteristics while ascending and descending a four-step staircase. The only significant difference between feet was found during the initial double-limb support (IDLS) phase of stair ascent, with the Flex-Foot providing a more symmetrical amputated:sound limb IDLS ratio compared with the SACH foot (1.03 versus 1.30). The increased IDLS time seen with the SACH foot reflects the inability to adequately advance the tibia and body weight over the prosthetic foot to achieve progression. This lack of progression and symmetrical gait pattern between limbs may be a function of the limited dorsiflexion range inherent with the SACH foot.