Intra-individual biomechanical effects of a non-microprocessor-controlled stance-yielding prosthetic knee during ramp descent in persons with unilateral transfemoral amputation.

BACKGROUND:: A stance-yielding mechanism for prosthetic knees may reduce lower limb loading during specific activities, but quantitative data are insufficient. OBJECTIVES:: To clarify the biomechanical effect of a non-microprocessor-controlled stance-yielding mechanism on ramp descent for individuals with unilateral transfemoral amputation. STUDY DESIGN:: Intra-subject intervention study. METHODS:: Seven individuals with unilateral transfemoral amputation underwent three-dimensional motion analysis of ramp descent with and without activating a stance-yielding mechanism. Regarding early-stance internal joint moment and ground reaction force, whole-group and subgroup analyses stratified by stance prosthetic knee flexion were performed to verify differences in prosthetic side and contralateral limb loading between conditions. RESULTS:: Whole-group analysis revealed significant reduction in early-stance prosthetic knee extension moment with stance-yielding mechanism activation. Changes in prosthetic side hip extension moment and contralateral limb loading were inconsistent between conditions. Subjects with prosthetic stance knee flexion walked slower with a smaller stride and greater increase in aft ground reaction force and ankle dorsiflexion moment when stance-yielding was activated. CONCLUSION:: Stance-yielding mechanism has a biomechanical potential to decrease excessive knee hyperextension. However, prosthetic side stance knee flexion induced by the stance-yielding mechanism might not necessarily reduce the mechanical load on residual hip or contralateral lower limb joints. CLINICAL RELEVANCE: This study showed individual variability in the possibility of reducing the load on the remaining lower limb when using a non-microprocessor-controlled stance-yielding knee. This suggests that individualized prosthetic management and monitoring the activities of individuals wearing a stance-yielding prosthetic knee are crucial to maximize the benefits of stance-yielding prosthetic knees.

Kinetic differences between level walking and ramp descent in individuals with unilateral transfemoral amputation using a prosthetic knee without a stance control mechanism.

BACKGROUND: Individuals with transfemoral amputation (TFA) have difficulty in descending ramps. Although individuals with TFA who descend ramps are speculated to have greater biomechanical demands, this has not been quantified. RESEARCH QUESTION: How do individuals with TFA wearing a prosthetic knee without a stance control mechanism adapt their gait biomechanics to a slightly declined surface? METHODS: We retrospectively analyzed data of level walking and ramp descent (5° decline) from six subjects with TFA who used a prosthesis without a stance control mechanism. Ground reaction force and joint moment, power, and kinematics were derived from three-dimensional motion capture, combined with force measurement. Kinematic and kinetic variables were compared during level walking and ramp descent using the paired tests. RESULTS: Compared with level walking, ramp descent increased the maximum contralateral vertical ground reaction force by 16% of the body weight, on average (standard deviation: 20%). Ramp descent tended to induce smaller concentric hip power during late swing and greater hip eccentric power on the prosthetic-side during late stance. Greater biomechanical demands during ramp descent were indicated by increased maximum medial ground reaction force on both sides, and eccentric joint power of the contralateral ankle during stance. SIGNIFICANCE: For individuals with TFA using a prosthetic knee without a stance control mechanism, descending a ramp can increase loading on the contralateral limb during the loading response; slower walking may alleviate the effect. Ramp descent can change prosthetic-side hip muscles' control of the swinging prosthetic limb, eccentric work on the contralateral ankle plantarflexors during stance, and mediolateral balance. All of these factors should be taken into consideration when individuals with TFA learn to descend a ramp.

Limb fitting for quadruple amputees: report of two cases of symmetrical peripheral gangrene caused by pneumococcal purpura fulminans.

BACKGROUND: We report our experiences of prosthetic fitting in quadruple amputees. Two patients underwent quadruple amputation after suffering from disseminated intravascular coagulation in conjunction with pneumococcemia with purpura fulminans. CASE DESCRIPTION AND METHODS: The first patient, a 52-year-old man, underwent bilateral transradial, left transtibial, and right transfemoral amputation, and the second patient, a 62-year-old man, underwent bilateral transradial and bilateral transfemoral amputation, both for symmetrical peripheral gangrene subsequent to septic shock. FINDINGS AND OUTCOMES: The amputations were accompanied by skin damage due to ischemic tissue changes both on the stumps and on the nose and/or lips. The combination of the intensive prosthetic rehabilitation program and supportive medical care led to completely independent functioning, including driving a car, with the use of four prosthetic limbs and a wheelchair in both cases. CONCLUSION: Early initiation of a multidisciplinary approach can properly address impairments and minimize future disability.