Below-knee Prosthesis Research Articles

Biomechanical effects of adding an articulating toe joint to a passive foot prosthesis for incline and decline walking.

Walking on sloped surfaces is challenging for many lower limb prosthesis users, in part due to the limited ankle range of motion provided by typical prosthetic ankle-foot devices. Adding a toe joint could potentially benefit users by providing an additional degree of flexibility to adapt to sloped surfaces, but this remains untested. The objective of this study was to characterize the effect of a prosthesis with an articulating toe joint on the preferences and gait biomechanics of individuals with unilateral below-knee limb loss walking on slopes. Nine active prosthesis users walked on an instrumented treadmill at a +5° incline and -5° decline while wearing an experimental foot prosthesis in two configurations: a Flexible toe joint and a Locked-out toe joint. Three participants preferred the Flexible toe joint over the Locked-out toe joint for incline and decline walking. Eight of nine participants went on to participate in a biomechanical data collection. The Flexible toe joint decreased prosthesis Push-off work by 2 Joules during both incline (p = 0.008; g = -0.63) and decline (p = 0.008; g = -0.65) walking. During incline walking, prosthetic limb knee flexion at toe-off was 3° greater in the Flexible configuration compared to the Locked (p = 0.008; g = 0.42). Overall, these results indicate that adding a toe joint to a passive foot prosthesis has relatively small effects on joint kinematics and kinetics during sloped walking. This study is part of a larger body of work that also assessed the impact of a prosthetic toe joint for level and uneven terrain walking and stair ascent/descent. Collectively, toe joints do not appear to substantially or consistently alter lower limb mechanics for active unilateral below-knee prosthesis users. Our findings also demonstrate that user preference for passive prosthetic technology may be both subject-specific and task-specific. Future work could investigate the inter-individual preferences and potential benefits of a prosthetic toe joint for lower-mobility individuals.

Distal Tibia Endoprosthesis Reconstruction after Resection of Aggressive Bone Tumors: Is it a Reliable Treatment Option?

Introduction: Primary bone tumours of the distal tibia are rare, and amputation was the treatment of choice in the past. Custom-made endoprosthesis reconstruction of the distal tibia has become a viable option in selected patients as a form of limb salvage for better function and cosmesis. It provides similar functional outcomes to below-knee amputation with a below-knee prosthesis. We investigated our cases' reliability, functional and oncological outcomes with distal tibia endoprosthesis reconstruction done for aggressive bone tumours. Methods: This is a retrospective review of 10 patients who underwent distal tibia endoprosthesis reconstruction at our centre from December 2007 to December 2021. This study aims to determine the clinical, oncological and functional outcomes using the Musculoskeletal Tumor Society (MSTS) Score and Toronto Extremity Salvage Score (TESS) and the survivorship of these implants. Results: The mean age of our patients is 29 years (range 12 to 53), with 60% males. The mean follow-up was 39.3 months (range 12 to 112). 50% of our cases were giant cell tumour of bone, 20% were osteosarcoma, and 10% were ewing’s, PVNS and pleomorphic sarcoma of the bone, respectively. Two patients passed away from advanced disease, where one was associated with local recurrence. The other case with local recurrence developed an acute infection post-resection of the recurrence. The infection resolved after repeated debridement and free muscle transfer. One patient had septic loosening of the implant and underwent below-knee amputation. Two-thirds of the patients remained disease free. The mean MSTS score for the 9 patients during their last follow-up is 87.8% (range 73.3 to 100). The mean TESS score for the 6 patients during their last follow-up is 84.4% (range 69.2 to 100). Conclusion: Our study concludes that distal tibia endoprosthesis reconstruction is a reliable treatment option for aggressive bone tumours and provides good function outcomes.

EMG-Based Control of Active Ankle-Foot Prosthesis

Most below-knee prostheses are manufactured in Iraq without considering the fast progress in smart prostheses, which can offer movements in the desired directions according to the type of control system designed for this purpose. The proposed design appears to have the advantages of simplicity, affordability, better load distribution, suitability for subjects with transtibial amputation, and viability in countries with people having low socio-economic status. The designed prosthetics consisted of foot, ball, and socket joints, two stepper motors, a linkage system, and an EMG shield. All these materials were available in the local markets in Iraq. The experimental results showed that the maximum range of motion to move the designed prosthetic in the sagittal and frontal planes reached 70% of the healthy foot range of motion relative to the signals of the gastrocnemius muscle of a healthy leg person. The angles that represented the range of motion achieved in various directions at the ankle joint were Dorsiflexion Angle (35˚), Plantar Flexion Angle (25˚), Inversion Angle (20˚), and Eversion Angle (15˚).

Case Report: Rehabilitation of bilateral below-knee and partial-hand amputations in a developing country

Limb ischemia is a complication of peripheral artery disease (PAD)which can lead to amputation. Amputation occurs in approximately 3-4% of PAD patients. In Indonesia, post-amputation patients are only hospitalized for the acute phase and the post-amputation rehabilitation programs must be done as an outpatient. This could be a barrier to the continuity of rehabilitation programs. A solution is the application of home-based rehabilitation programs. A 57-year-old female was referred from the Cardiothoracic Surgery Outpatient Clinic post-amputation with bilateral below-knees and partial-hands amputation after being diagnosed with PAD. On initial examination, all her elbows, wrists, thumbs, hips, and knees showed weakness. The patient received neuromuscular electrical stimulations (NMES) as well as a home-based rehabilitation programs. On the second examination, after considering the data from the clinical finding and supporting examination, the patient received bilateral below-knee prostheses and bilateral functional partial-hand prostheses, created using 3D printing technology with polylactic acid material. After a few months, she was able to do most of her activities of daily living (ADLs) independently, work as a shopkeeper in her store, and feel more confident interacting with others. A comprehensive rehabilitation programs, patient adherence to exercise, and caregiver support are critical to improving functional capacity and the quality of life in a patient with bilateral below-knee and bilateral partial-hand amputation caused by PAD.

Experimental, Theoretical, and Numerical Analysis of Laminated Composite Prosthetic Socket Reinforced with Flax and Cotton Fibers

A lot of work has been done to enhance the mechanical properties of natural fiber composites to increase their strength and applicability. This research aims to investigate the utilization of natural fibers for below-knee prosthesis socket manufacture using the vacuum bagging technique experimentally, theoretically, and numerically. Lamination groups of different layering arrangements were evaluated by tensile tests. The finite element methodology (FEM) was utilized by noting the dispersion of safety factors, equivalent Von-Mises stress, and total deformation, while the theoretical part estimated Poisson's ratio, volume fraction, failure index, and theoretical safety factor. The study found that the number and type of fibers affected mechanical properties, in addition, that combining natural and artificial reinforcements permits the creation of high-performance bio-composites. FEM results coincided with both the theoretical and experimental results, with lamination 9 having the highest modulus of elasticity (5.6 GPa) and tensile strength (423 MPa). This work uncovered the properties of the proposed hybrid fiber-reinforced composites that haven't been exasperated up to the present and showed that sockets can be assembled from sustainable, low-risk materials without sacrificing the composite materials' strength. The study found that bio-composites with better performance could be created by combining synthetic with natural reinforcements.

Case Report: Rehabilitation of bilateral below-knee and partial-hand amputations in a developing country

Limb ischemia is a complication of peripheral artery disease (PAD)which can lead to amputation. Amputation occurs in approximately 3-4% of PAD patients. In Indonesia, post-amputation patients are only hospitalized for the acute phase and the post-amputation rehabilitation programs must be done as an outpatient. This could be a barrier to the continuity of rehabilitation programs. A solution is the application of home-based rehabilitation programs. A 57-year-old female was referred from the Cardiothoracic Surgery Outpatient Clinic post-amputation with bilateral below-knees and partial-hands amputation after being diagnosed with PAD. On initial examination, all her elbows, wrists, thumbs, hips, and knees showed weakness. The patient received neuromuscular electrical stimulations (NMES) as well as a home-based rehabilitation programs. On the second examination, after considering the data from the clinical finding and supporting examination, the patient received bilateral below-knee prostheses and bilateral functional partial-hand prostheses, created using 3D printing technology with polylactic acid material. After a few months, she was able to do most of her activities of daily living (ADLs) independently, work as a shopkeeper in her store, and feel more confident interacting with others. A comprehensive rehabilitation programs, patient adherence to exercise, and caregiver support are critical to improving functional capacity and the quality of life in a patient with bilateral below-knee and bilateral partial-hand amputation caused by PAD.

Enhancement of the flexural and impact properties laminated biocomposite by new natural fibres for artificial lower limb socket

ABSTRACT For several purposes, involving sickness, injuries, and genetic abnormalities, artificial limbs may be necessitated. Artificial limbs must be altered and modified regularly since the human physique vagaries with time owing to gaining or changing body mass. The utilisation of natural fibres as a potential substitute for fabricating a below-knee prosthesis socket will be highlighted in this study. To construct a below-knee socket, a vacuum bagging process was utilised. Woven flax, sisal, cotton, carbon, and glass fibre have formed in the laminates. The effect of various fibre stacking patterns on certain physical and mechanical properties was investigated. Multiple mechanical tests, including flexural, maximum shear stress, and impact tests, were performed as part of the experimental portion of this work. The findings of this study revealed that ingesting various kinds of reinforcing materials had a significant impact on the characteristics of fabricated composites, with the virtues of (flexural strength, flexural modulus, max. Shear stress, impact strength, and fracture toughness) improving as the volume fraction of materials increased. This review focuses on the assets of flax, sisal, and cotton fibre hybrid strengthened PMMA composites (hybridised in a variety of volume proportions and lamination layups) that have yet to be tested as a superior alternative for the creation of prosthetic sockets.

Unilateral below-knee prosthesis users walking on uneven terrain: The effect of adding a toe joint to a passive prosthesis

Lower limb prosthesis users cite uneven terrain as a challenging surface to walk on. We sought to determine whether adding a Flexible toe joint to a prosthetic foot would be preferred by unilateral below-knee prosthesis users relative to a Locked (non-articulating) toe joint for walking on uneven terrain. We also quantified lower limb joint kinetics for the Locked and Flexible toe joint configurations. Five of our nine participants preferred the Flexible toe joint when walking on uneven terrain, yet from a biomechanical standpoint, the reason for this is unclear. All participants exhibited reductions in prosthetic limb net positive hip joint work when walking with a Flexible toe joint (11%; p < 0.05). For other parameters (e.g., prosthetic side knee joint moments) we observed high inter-subject variation, which adds to a growing body of literature highlighting the need for subject-specific data analyses in lower limb prosthetics research.

DESAIN DAN SIMULASI SOCKET PROSTESIS BAWAH LUTUT DENGAN VARIASI MATERIAL BERBASIS KOMPOSIT

Each year, the number of disabled people in Indonesia increases. About 2.4 million people had some trouble walking in 2014. It includes 650,000 individuals who have significant difficulty walking and ascending stairs. Lower limb prostheses are an option for those who are unable to walk due to leg amputation. One of the most necessary parts of the below-knee prosthesis is the socket. Almost the local prosthetics socket did not give adequate information about the specification. It is a weakness of the local product because there is no guarantee of product safety. The lack of references and standards makes it difficult for manufacturers to improve their products to compete with imported products. This research is focused on the design and simulation of prosthesis sockets with various composite-based materials. The simulation method was adapted from ISO 10328 standard as the testing standard for prosthetics foot. The result shows that the sockets can be used for Indonesians with a calf circumference between 317-345 mm. The simulation results show that the suitable material for use is carbon fiber composite material with a thickness of 3 mm with a bolt hole of 6 mm.

Design and development of patient-specific prosthetic socket for lower limb amputation

The work aims to design and development of a prosthetic socket for lower limb amputation with 3D printing technology for a patient. It is focused on the finite element-based simulation and analysis by utilizing CT based three-dimensional (3D) model. In this study, image processing software is used for extracting models from CT images and obtained models are modified in CAD modeling software in STL format. These files are examined in ANSYS simulation to performing the static and dynamic analysis of the prosthetic stump and socket. Based on the simulation results, the model is to prepare with the 3D printer. The results from the 3D model simulation can be used to estimate the pressure distribution. The function of the below-knee prosthesis is to control the leg under static and dynamic conditions. The prosthetic sockets evolution and prefabrication by using finite element approach very interesting topic in this research work for the fabricators. Finally, it helps contribute to an overall prefabrication evaluation system to allow healthcare providers. The patients are comfortable with the transtibial prosthetics made of 3D printers with the simulation process to fit.

Impact and Mechanical Properties Modifying for Below Knee Prosthesis Socket Laminations by using Natural Kenaf Fiber

The main issue of this research to improve and develop the mechanical properties of the socket composite material for below-knee (BK) prosthesis; several composite materials were proposed, consisting of perlon, Kevlar and carbon fibers, and natural fibers were added as a new idea for the research. Making the theory calculations were for several layers of materials, by using mathematical model, to obtain the best lamination with and without kenaf by calculating the best modulus of elasticity and the best E/ρ ratio. So the experimental tests were carried out on the lamination with a total of 12 layers for thickness (4 mm) each of them, (Group G/withot kenaf) and (Group D/with kenaf). The experimental part included examining the samples by tensile test, bending test, impact test. The results of the tensile test results were for the first lamination and the second lamination for the ultimate tensile strength (134.47 MPa) and (187.39MPa) respectively. As for the elasticity modulus, it was as follows (16.78 GPa) without kenaf and (17.49 GPa) for kenaf lamination. Through the theoretical and experimental results, it was found that the use of natural kenaf fibers led to the improvement of the maximum tensile strength 39.35% and modulus of elasticity 4.23%. The impact resistance was improved by using kenaf by 8.8% due to its durability higher than perlon fiber.

Unilateral Below-Knee Prosthesis Users Walking on Uneven Terrain: The Effect of Adding a Toe Joint to a Passive Prosthesis

Unilateral Below-Knee Prosthesis Users Walking on Uneven Terrain: The Effect of Adding a Toe Joint to a Passive Prosthesis

Perturbation recovery during walking is impacted by knowledge of perturbation timing in below-knee prosthesis users and non-impaired participants

Previous research found that below-knee prosthesis users proactively increase their lateral margin-of-stability on their impaired side in anticipation of an impending perturbation when the timing is predictable and potentially directed toward the impaired limb. While knowledge of perturbation timing and direction influences proactive strategies, the consequences of such knowledge and anticipatory behavior on recovery from perturbations is unclear. This study characterized center-of-mass (CoM) dynamics of below-knee prosthesis users and non-impaired controls following a lateral perturbation when the perturbation direction is known but a priori knowledge of the timing of perturbation is either known or unknown. Across groups, CoM displacement during perturbation exposure increased when directed towards the impaired or non-dominant limb with no influence of timing knowledge. In addition, peak CoM displacement was less with known timing irrespective of the perturbation direction. Generally, the CoM displacement during perturbation exposure correlated well with the CoM medial-lateral velocity during unperturbed walking, supporting evidence that human response dynamics to lateral perturbations are influenced by the instantaneous state of the body’s momentum.

Real-Time Interface Algorithm for Ankle Kinematics and Stiffness From Electromyographic Signals.

Shortcomings in capabilities of below-knee (transtibial) prostheses, compared to their biological counterparts, still cause medical complications and functional deficit to millions of amputees around the world. Although active (powered actuation) transtibial prostheses have the potential to bridge these gaps, the current control solutions limit their efficacy. Here we describe the development of a novel interface for two degrees-of-freedom position and stiffness control for below-knee amputees. The developed algorithm for the interface relies entirely on muscle electrical signals from the lower leg. The algorithm was tested for voluntary position and stiffness control in eight able-bodied and two transtibial amputees and for voluntary stiffness control with foot position estimation while walking in eight able-bodied and one transtibial amputee. The results of the voluntary control experiment demonstrated a promising target reaching success rate, higher for amputees compared to the able-bodied individuals (82.5% and 72.5% compared to 72.5% and 68.1% for the position and position and stiffness matching tasks respectively). Further, the algorithm could provide the means to control four stiffness levels during walking in both amputee and able-bodied individuals while providing estimates of foot kinematics (gait cycle cross-correlation >75% for the sagittal and >90% for the frontal plane and gait cycle root mean square error <7.5° in sagittal and <3° in frontal plane for able-bodied and amputee individuals across three walking speeds). The results from the two experiments demonstrate the feasibility of using this novel algorithm for online control of multiple degrees of freedom and of their stiffness in lower limb prostheses.

A modified shank for below knee prosthesis

A below knee (BK) prosthesis is a device used to compensate for missing limb segments in patients with BK amputations as an aid for locomotive and other daily activities It consists of three main parts: socket, shank, and artificial foot. The shank is merely a shaft of a suitable length to serve as a frame structure to transfer biomechanical forces between the socket and foot. In traditional BK prostheses, the shank is made from rigid metallic or composite material tube (Teflon), while in the current work, a modified version is suggested with internal stiffness and damping characteristics to act as energy storage and shock absorber. A mathematical model was thus employed to analyse the impact behaviour from walking gait, and the main parameters studied were the effective mass of impact, loading rate, and knee pre-swing angular velocity. The modified prosthesis was tested with a BK amputation patient and compared with a traditional prosthesis in force platform and treadmill tests. The results showed some improvement in patient gait parameters; at stance phase, it smoothed the GRF curve; at heel strike, both the effective mass of impact and loading rate increased by 16% and 22%, indicating good impact reduction, and at pre swing, it increased the initial flexion angle and angular velocity by 13% and 15%, respectively, enhancing the swing phase.

A Rare Case of Lower Limb Gangrene Following Anterior Exenteration in a Previously Irradiated Pelvis

Limb-threatening ischemia following arterial thrombosis in a patient with no known history of arterial disease or vascular injury following surgery is difficult to explain. This case report illustrates a rare complication of arterial thrombosis leading to limb gangrene in a patient with recurrent carcinoma cervix who underwent anterior exenteration. A 43-year-old woman irradiated 10 years back for FIGO stage IIA carcinoma cervix presented with recurrence. Since the workup revealed localized disease, surgery was planned. Under general anesthesia with an epidural catheter in situ, patient was placed in lithotomy position and abdomen opened through a lower vertical midline incision. As the lesion was adherent to urinary bladder, a decision was made to do anterior exenteration with uretero-colostomy. The surgery lasted for 7 h, and patient was placed in head-low position for more than 3 h to assist small-bowel packing. Postoperatively, patient developed ischemia of right lower leg with documented thrombosis of right common femoral artery. As the arterial embolectomy failed and gangrene had set in, the limb was amputated on the fourth postoperative day. At the time of this write up, the patient has completed 5 years of disease-free status. She is rehabilitated with the below-knee prosthesis and is mobile. Prolonged lithotomy positioning in the presence of a prior history of radiation may be associated with arterial thrombosis which can threaten limb perfusion, which if not diagnosed and treated early can result in limb gangrene.

Does Decreasing Below-Knee Prosthesis Pylon Longitudinal Stiffness Increase Prosthetic Limb Collision and Push-Off Work During Gait?

Investigations have begun to connect leg prosthesis mechanical properties and user outcomes to optimize prosthesis designs for maximizing mobility. To date, parametric studies have focused on prosthetic foot properties, but not explicitly longitudinal stiffness that is uniquely modified through shock-absorbing pylons. The linear spring function of these devices might affect work performed on the body center-of-mass during walking. This study observed the effects of different levels of pylon stiffness on individual limb work of unilateral below-knee prosthesis users walking at customary and fast speeds. Longitudinal stiffness reductions were associated with minimal increase in prosthetic limb collision and push-off work, but inconsistent changes in sound limb work. These small and variable changes in limb work did not suggest an improvement in mechanical economy due to reductions in stiffness. Fast walking generated greater overall center-of-mass work demands across stiffness conditions. Results indicate limb work asymmetry as the prosthetic limb experienced on average 61% and 36% of collision and push-off work, respectively, relative to the sound limb. A series spring model to estimate residuum and pylon stiffness effects on prosthesis energy storage suggested that minimal changes to limb work may be due to influences of the residual limb which dominate the system response.

Clinical and demographic characteristics of patients with lower limb amputation

Aim: Lower limb loss affects an individual’s ability to stand, transfer, and ambulate. The aim of this study is to assess clinical and demographic characteristics of patients with lower limb amputation.Materials and Methods: Our study is a retrospective cohort study. 836 patients with lower limb amputation applied to our hospital between January 2012 and May 2013 were included in this study. Demographic and clinical characteristics of patients were reviewed and saved from patient’s folder. Descriptive variables were shown as mean±standard deviation(min–max). And categorical variables were shown as the number of cases (n%).SPSS software Version 15.0 was used in the evaluation of the data.Results: The mean age of total 836 lower limb amputees was 36.12±11.69 years (9-78). The percentage of unilateral amputation was 770(92.3%) and bilateral lower limb amputation was 59(7.1%). According to the level of amputation, 456(54.5%) of the patients had unilateral above-knee, 236(28.3%) had unilateral below-knee amputation. For etiology, we found that 373(44.6%) of them were traffic accidents, 103(12.5%) occupational accidents. The majority of patients 456(54.5%) were ambulated microprocessor-controlled above-knee prosthesis and then below-knee prosthesis with active vacuum system 224(26.7%).Conclusion: Although trauma is recognized to be the most common cause of amputation among applying amputees, we think that those amputees do not reflect the general profile in our country but that it is instructive with regard to the features of amputees. This data is important for the community rehabilitation of amputees and the development of new prosthetics.

Widely Divergent Congenital Inferior Tibiofibular Diastasis with Separate Soft-Tissue Cover and Persistent Sciatic Artery: A Previously Unreported Combination

We report a case of a child with widely divergent congenital inferior tibiofibular diastasis with persistent sciatic artery (PSA). The dysplastic tibia and fibula were widely divergent, and the fibula was displaced proximally and medially with the foot alongside the thigh between the 2 legs, with PSA diagnosed on computed tomography angiogram. The child was treated with fibula-foot complex excision and below-knee prosthesis and was ambulating independently at 1-year follow-up. The combination of a major structural anomaly (tibiofibular diastasis with a separate soft-tissue cover) and an unusual vascular malformation (PSA) has not been reported previously and made surgical reconstruction challenging.

A unique association of an ancient Indian custom of body roasting and the postpartum psychosis responsible for the occurrence of major burns: A case report and challenges posed by postpartum psychosis in the treatment of burns

Introduction: We report a unique association of an ancient Indian custom of postdelivery mother roasting and postpartum psychosis responsible for the causation of major burns. Materials and Methods: A 20-year-old postpartum female reported with 40% second- and third-degree total body surface area burns. The combination of the ancient Indian custom of mother roasting and postpartum psychosis led to these major burns. The conventional treatment of burns in the form of IV fluids, antibiotics, and dressings with silver sulfadiazine creams was carried out. The psychiatrist was consulted, and the antipsychotic medicines were started for an altered behavior. One month after the burns, she developed deep-vein thrombosis with venous gangrene of the left leg for which she required a below-knee amputation. She required 45 days of hospitalization and six surgical procedures in the form of debridement and split-thickness skin grafting. Problems such as hypotension, noncooperation due to the wild swing in the moods were overcome by proper fluid and electrolyte management, an adjustment in antipsychotic medicines, appropriate postoperative care, and chest physiotherapy. Results: One year of follow-up showed good stable scars. At present, she can perform all domestic as well as labor work on the farm, with the help of a below-knee prosthesis. There is no element of psychotic behavior at present. Conclusion: This case report sheds light on an ancient Indian custom of mother roasting and postpartum psychosis and its dangers in contracting severe burn injuries. Challenges posed by postpartum psychosis in the treatment of burns have been discussed.