View clinical trials related to Lower Limb Amputation Knee.
Filter by:Lower limb amputation is common in the United States, with approximately 150,000 amputations annually. Most individuals walking with a prosthesis demonstrate asymmetrical loading-i.e., they favor the amputated side by placing more weight and increased ground reaction forces through the intact limb-which likely contributes to increased metabolic cost of walking. Lack of adequate muscular strength in the lower limb to attenuate these forces places increased stress on the joints, which may be displaced proximally, and may play a role in reported knee and hip pain in the intact limb. Lower limb muscle weakness following amputation has been well documented. Increasing quadriceps strength is important after an amputation because it is positively correlated with gait speed. Gait speed may also be associated with successful community mobility, which leads to improved quality of life following amputation. Individuals with amputation who resume an active lifestyle are able to maintain strength. However, these individuals represent a minority of persons with lower limb amputation; most individuals report more barriers than motivators to adopt an active lifestyle. Ischemic conditioning (IC) may strengthen leg muscles and reduce the metabolic cost of activity after amputation. In IC, the limb is exposed to brief, repeated bouts of ischemia (reduced blood flow) immediately followed by reperfusion. IC has been shown to improve muscle performance in healthy and diseased populations. IC has also been used more recently in patients with peripheral artery disease (PAD) as an intervention to improve function, such as walking ability. Acute exposure to IC increases muscle strength and activation, both in healthy, active individuals and in those with severe neuromuscular dysfunction, such as stroke survivors. IC also attenuates muscular fatigue. Increased fatigue resistance at submaximal contraction levels following IC may be due to increased neural activation of skeletal muscle. Changes in neural activation of muscle may be particularly beneficial during cortical reorganization after amputation. Reduced quadriceps fatigue during submaximal activities may also drive changes in gait kinematics, such as increased knee flexion during loading and mid-stance. Exposure to IC may also increase the oxidative properties of skeletal muscle, offering a direct pathway to reduce metabolic cost. Therefore, IC may lead to cellular changes that lower the metabolic cost of activity. The primary aim of this study is to quantify the benefits of acute and chronic IC on quadriceps strength and walking economy in individuals with PAD and history of lower limb amputation.
Many amputees suffer from Phantom Limb Pain (PLP), a condition where painful perceptions arise from the missing limb. Leg amputees wear prostheses that do not provide any sensory feedback, apart from the stump-socket interaction. Increased physical effort associated with prosthesis use as well as discomfort often lead to rejection of artificial limbs. Additionally, the perception of the missing limb and its brain representation, do not match-up with what amputees see (the prosthesis) and this is made worse by the absence of sensory feedback. Therefore, re-establishing the sensory flow of information between the subject's brain and the prosthetic device is extremely important to avoid this mismatch, which creates inadequate embodiment. This study focuses on improving functional abilities and decreasing PLP in amputees thanks to the use of a system able to generate a sensory feedback (SF), which will be provided with a non-invasive electrical stimulation (ES). First, the possibility of enhancing the performance in different functional tasks thanks to the use of SF will be explored. Furthermore, it will be evaluated if SF enhances the prosthesis embodiment and helps restoring a multisensory integration (visuo-tactile), potentially providing also a pain relief. Once tested this system on amputees, also people with peripheral neuropathy and sensory loss will be recruited. Diabetic patients can suffer from symmetrical polyneuropathy (DSPN), which is a common complication caused by prolonged glucose unbalanced levels that lead to nerve damage. Non-invasive ES has been proposed and used as a therapy to treat the chronic pain conditions. In particular, TENS (transcutaneous electrical nerve stimulation) is a type of non-invasive ES, which is able to activate large diameter afferent fibers. The gate control theory of pain states that these large diameter fibers inhibit central nociceptive transmission with a resultant decrease in pain perception. Therefore, also these patients will be recruited to see whether adding a non-invasive SF can enhance their functional motor abilities while diminishing their pain. The subjects will perform a pool of the following tasks, depending on their residual abilities: motor tasks (walking on ground level and on stairs), cognitive tasks (dual tasks), subjective evaluation of prosthesis weight and description of sensations from ES. Some tasks will be performed in Virtual Reality environments with and without an active stimulation.