Designing, Production and Assessment of an Ankle Turner Unit of Prosthesis in Subjects with Unilateral Below Knee Amputation

The motor ability of persons with amputation is generally lower compared with those without amputation. One of the most important factors affecting motor ability in amputees is the function and comfort in using a prosthetic limb. The aim of this study was design, production and assessment of an ankle turner unit of prosthesis in subjects with unilateral below knee amputation
In this applied research, to provide the possibility of rotation of the ankle section of the prosthetic limb in required conditions and the ability to return and disengage to the initial position, a very light weight unit was designed. After the design phase, the unit was produced using light and durable materials by milling and cutting machinery. The unit was designed and made to be compatible with mating sections of the host prosthetic limb without the need for change in the host prosthetic limb or use of any interface. The effect of this unit on the ability to sit cross-legged and to kneel was evaluated in 20 patients.
The produced unit improved transversal rotation in the ankle joint of the prosthetic limb. To provide effective ankle range of motion in amputee patients, this unit was tested on 20 persons with unilateral transtibial amputation. In all patients, transversal rotation range of motion of the foot ankle resulted in a significant improvement in patterns for cross-legged sitting (p=0.04) and kneeling positions (p=0.006).
In general, using this unit increases the effective range of motion in amputated limbs which can be beneficial to motor ability of the amputee patients.