Does a torsion adapter improve functional mobility, pain, and fatigue in patients with transtibial amputation?

Background: Turning gait is an integral part of daily ambulation and likely poses a greater challenge for patients with transtibial amputation compared with walking a straight pathway. A torsion adapter is a prosthetic component that can increase transverse plane compliance of the prosthesis and decrease the torque applied to the residual limb, but whether this will improve patients' mobility, pain, and fatigue remains unknown.

Questions/purposes: Does prescription of a torsion adapter translate to improvements in (1) functional mobility and (2) self-perceived pain and fatigue in moderately active patients with lower limb amputation?

Methods: Ten unilateral transtibial amputees wore a torsion or rigid adapter in random order. Functional mobility was assessed through a field measurement using an activity monitor and through a laboratory measurement using a 6-minute walk test that included turns. The residual limb pain grade assessed self-perceived pain and the Multidimensional Fatigue Inventory assessed fatigue.

Results: We found relatively small functional differences for amputees wearing a torsion adapter versus a rigid adapter. Amputees wearing a torsion adapter tended to take more low- and medium-intensity steps per day (331 ± 365 and 437 ± 511 difference in steps; effect size = 0.44 and 0.17; confidence interval [CI], 70-592 and 71-802; p = 0.019 and 0.024, respectively). They also experienced less pain interference with activities (1.9 ± 1.7 change in score; effect size = 0.83; CI, 0.3-3.4; p = 0.026) when wearing a torsion adapter. However, these patients took a similar number of total steps per day, walked a comparable distance in 6 minutes, and reported similar residual limb pain and fatigue.

Conclusions: For a moderately active group of amputees, the torsion adapter did not translate to substantial improvements in functional mobility and self-perceived pain and fatigue. The small increases in low- and medium-intensity activities with less pain interference when wearing a torsion adapter provides evidence to support prescribing this device for amputees with difficulty navigating the household and community environments.