Above knee amputee

Most impedance-based walking controllers for powered knee-ankle prostheses use a finite state machine with dozens of user-specific parameters that require manual tuning by technical experts. These parameters are only appropriate near the task ( e.g ., walking speed and incline) at which they were tuned, necessitating many different parameter sets for variable-task walking. In contrast, this paper presents a data-driven, phase-based controller for variable-task walking that uses continuously-variable impedance control during stance and kinematic control during swing to enable biomimetic locomotion...

CONTEXT: Rehabilitation following lower extremity amputation presents multiple challenges, many related to the traditional prosthesis (TP) socket. Without skeletal loading, bone density also rapidly decreases. Transcutaneous osseointegration for amputees (TOFA) surgically implants a metal prosthesis attachment directly into the residual bone, facilitating direct skeletal loading. Quality of life and mobility are consistently reported to be significantly superior with TOFA than TP. OBJECTIVE: To investigate how femoral neck bone mineral density (BMD, g/cm2 ) changes for unilateral transfemoral and transtibial amputees at least five years following single-stage press-fit osseointegration...

The association between combat-related traumatic injury (CRTI) and bone health is uncertain. A disproportionate number of lower limb amputees from the Iraq and Afghanistan conflicts are diagnosed with osteopenia/osteoporosis, increasing lifetime risk of fragility fracture and challenging traditional osteoporosis treatment paradigms. The aim of this study is to test the hypotheses that CRTI results in a systemic reduction in bone mineral density (BMD) and that active traumatic lower limb amputees have localized BMD reduction, which is more prominent with higher level amputations...

Introduction Amputees frequently suffer from chronic pain in both their residual limbs (RLP) and phantom limbs (PLP) following their amputation. Targeted muscle reinnervation (TMR) is a nerve transfer technique that has been demonstrated to improve pain secondarily and at time of amputation. The goal of this study is to report on the efficacy of primary TMR at time of above-knee level amputations in the setting of limb-threatening ischemia or infection. Materials and Methods This is a retrospective review of a single-surgeon experience with TMR in patients undergoing through- or above-knee level amputations from January 2018 to June 2021...

BACKGROUND: After above-knee amputation, the missing biological knee and ankle are replaced with passive prosthetic devices. Passive prostheses are able to dissipate limited amounts of energy using resistive damper systems during "negative energy" tasks like sit-down. However, passive prosthetic knees are not able to provide high levels of resistance at the end of the sit-down movement when the knee is flexed, and users need the most support. Consequently, users are forced to over-compensate with their upper body, residual hip, and intact leg, and/or sit down with a ballistic and uncontrolled movement...

Inverse dynamics analysis of prosthetic legs with polycentric knees is complex due to increased number of links. The present work proposes a simple and general method called equivalent system (ES) analysis. The ES analysis provides forces and moment at hip joint as well as at the functional knee centre (FKC), the instant centre of the polycentric knee. The input to the ES analysis is the motion data. For validation of the proposed method, synthetic motion data for the swing phase of walking with prosthetic legs having different knees are generated by simulations using ADAMS...

Proximal tibia fractures are generally open fractures resulting in life-threatening complications. There is an increase in the prevalence of compartment syndrome post-tibial fractures. Though fasciotomy and wound debridement is the choice of treatment in such conditions, amputation becomes a necessity when there is widespread muscle and tissue damage. Specifically, compartment syndrome involving the lower limb is distressing as its symptoms can be misleading at times resulting in delayed diagnosis and hence life-threatening complications...

INTRODUCTION: Femoral neck fractures in patients with a history of above knee amputation present as a strain for orthopedic surgeons due to the difficulty of positioning and handling of the limb for proper reduction. Surgical treatment options typically involve open reduction internal fixation versus arthroplasty depending on patient factors such as age, surgeon skill, and available equipment. CASE REPORT: We present a case of a femoral neck fracture (OTA 31-B2) in a relatively active 89-year-old Caucasian male after a ground level fall that has been ambulating with a prosthesis since his teenage years...

Many people struggle with mobility impairments due to lower limb amputations. To participate in society, they need to be able to walk on a wide variety of terrains, such as stairs, ramps, and level ground. Current lower limb powered prostheses require different control strategies for varying ambulation modes, and use data from mechanical sensors within the prosthesis to determine which ambulation mode the user is in. However, it can be challenging to distinguish between ambulation modes. Efforts have been made to improve classification accuracy by adding electromyography information, but this requires a large number of sensors, has a low signal-to-noise ratio, and cannot distinguish between superficial and deep muscle activations...

Vascular patients, an inherently older, frail population, account for >80% of major lower extremity amputations (transtibial or transfemoral) in the United States. Retrospective data have shown that early physical therapy and discharge to an acute rehabilitation facility decreases the postoperative length of stay (LOS) and expedites ambulation. In the present study, we sought to determine whether patients treated with the lower extremity amputation protocol (LEAP) will have improved outcomes. We performed a nonrandomized prospective study of vascular patients undergoing an amputation from January 2019 to February 2020...

Robotic leg prostheses promise to improve the mobility and quality of life of millions of individuals with lower-limb amputations by imitating the biomechanics of the missing biological leg. Unfortunately, existing powered prostheses are much heavier and bigger and have shorter battery life than conventional passive prostheses, severely limiting their clinical viability and utility in the daily life of amputees. Here, we present a robotic leg prosthesis that replicates the key biomechanical functions of the biological knee, ankle, and toe in the sagittal plane while matching the weight, size, and battery life of conventional microprocessor-controlled prostheses...

There is lack of information about bone mineralization at the lumbar spine and bilateral hips of athletes with unilateral lower limb amputation. The present study assessed for the first time the areal bone mineral density at the lumbar spine and at the hip of the able and impaired leg by means of Dual-Energy X-Ray Absorptiometry using a large sample ( N = 40) of male athletes. Results showed that bone demineralization in athletes with unilateral lower limb amputation is found at the impaired hip but not at the lumbar spine and may therefore be site-specific...

After above-knee amputation, the missing biological knee and ankle are commonly replaced with a passive prosthesis, which cannot provide net-positive energy to assist the user. During activities such as sit-to-stand, above-knee amputees must compensate for this lack of power using their upper body, intact limb, and residual limb, resulting in slower, less symmetric, and higher effort movements. Previous studies have shown that powered prostheses can improve symmetry and speed by providing positive assistive power...

A non-optimal prosthesis integration into an amputee's body schema suggests some important functional and health consequences after lower limb amputation. These include low perception of a prosthesis as a part of the body, experiencing it as heavier than the natural limb, and cognitively exhausting use for users. Invasive approaches, exploiting the surgical implantation of electrodes in residual nerves, improved prosthesis integration by restoring natural and somatotopic sensory feedback in transfemoral amputees...

UNLABELLED: There are approximately 2 million people living with the loss of a major limb in America. It is estimated that 95% of these will have some form of pain associated with their amputation. Phantom limb pain, related to symptomatic neuromas, contributes to amputation morbidity and can be difficult to treat. Studies have shown that targeted muscle reinnervation (TMR), by giving symptomatic neuromas "somewhere to go and something to do," can be an effective therapy. However, a large proportion of surgeons still treat symptomatic neuromas by burying them in nearby tissue...

Ambulation with existing prostheses is extremely difficult for individuals with bilateral above-knee amputations. Commonly prescribed prostheses are passive devices that cannot replace the biomechanical functions of the missing biological legs. As a result, most individuals with bilateral above-knee amputations can only walk for short distances, have a high risk of falling, and are unable to ascend stairs with a natural gait pattern. Powered prostheses have the potential to address this issue by replicating the movements of the biological leg...

Transfemoral amputees who run are required to learn how to control their prosthetic leg motion to avoid falling with unintended prosthetic knee flexion because the function of the existing prosthetic knee for running is likened to a simple hinge joint during stance. However, the risk of falling and injury is a barrier to participation in sports and exercise. We have addressed this concern by developing a passive mechanism for a prosthetic knee; however, the mechanism that locks knee flexion with ground reaction forces (GRFs) could not completely avoid unintended prosthetic knee flexion...

The number of patients with unilateral above-knee amputation (AKA) due to non-vascular causes has remained stable over the years, at 0.92 per 1000 people per year. Post-AKA individuals are at risk of experiencing a higher incidence of chronic pain. Post rehabilitation, it is estimated that between 16-62% of patients with musculoskeletal disabilities fail to meet the minimum criteria for physical activity in comparison to a healthy population. The current study included 14 participants (11 men and 3 women) with a mean age of 46...

Limb loss at the transfemoral or knee disarticulation level results in a significant decrease of mobility. Powered lower limb prostheses have the potential to provide increased functional mobility and return individuals to activities of daily living that are limited due to their amputation. Providing power at the knee and/or ankle, new and innovative training is required for the amputee and the clinician to understand the capabilities of these advanced devices. This protocol for functional mobility training with a powered knee and ankle prosthesis was developed while training 30 participants with a unilateral transfemoral or knee disarticulation amputation at a nationally ranked physical medicine and rehabilitation research hospital...

BACKGROUND: Lower extremity amputation related to diabetes is a serious outcome, which can have devastating effects on the patient and family. The epidemiology of amputations has recently been used as a possible measure of the adequacy of medical prevention and treatment of diabetes and diabetic foot complications. OBJECTIVES: To report on patients undergoing amputations at one medical center in Israel, their co-morbidities, and the outcomes. METHODS: A retrospective chart study was conducted of amputees operated between 1 September 2017 and 30 September 2018...