Crutch Design Research Articles

Development of a Crutch Substitute for Mimicking Human Natural Walking Gait

In order to resolve some of the disadvantages of conventional crutch designs, as well as some of the existing crutch-substitute devices, available on the market, a novel Exo-Limb crutch design is presented. The Exo-limb is a hands-free crutch meant to enhance and replace standard underarm crutches and other competitive products during injury rehabilitation. The focus of this research has been on creating a cost-effective passive device that mimics humans natural walking gait using purely mechanical components. Prior to the design, human natural treadmill walking was monitored by a 3D Motion Capture System and a reference end¢‚¬€œfoot trajectory with a ¢‚¬Ëœteardrop shape¢‚¬„¢ was acquired. Considering the design objectives, natural human walking and comfort, and other factors such as load capacity and weight of the device, the final design was determined. In order to satisfy the design objectives a kinematic synthesis, previously developed by one of the co-authors, is applied to test if the end¢‚¬€œfoot trajectory of the designed crutch substitute smoothly follows the desired reference, ¢‚¬Ëœteardrop shape¢‚¬„¢ in the vicinity of two specified task points, heel strike and toe off. A prototype of the final design was fabricated and its performance was tested by 2 mph treadmill walking. The research and developments made in this project with regard to mimicking the natural walking gait are important contributions that find applications in different areas, such as military, robotic locomotion, injury recovery and physical therapy.

Common problems with the conventional design of crutches: Proposing a safer design and discussing the potential impact

This study aims to address the need for improving low-tech and low-cost assistive technology for the population in low and middle-income countries and bridge an assistive technology access divide. In general, the assistive technology industry is extremely specialized and typically designed for high-income settings. This can be inferred from the variety of options for high-end wheelchairs and devices and the limited number of design solutions for a basic walking aid, such as the crutch. Moreover, available designs of assistive devices are often not suitable for the physical, social, and cultural environment of users resulting in a high abandonment rate (as high as 75%, although figures vary depending on the type of assistive devices). In pursuit of addressing this problem, a survey was conducted to explore what users find most challenging with current designs of a tradition walking aid, the crutch. Drawing on 2 primary datasets gathered through surveying 50 participants in various rehabilitation centers in Korea and interviewing 5 users in a refugee camp in Malawi who use crutches, the current study offers a description of the underlying factors of satisfaction on the individual level and suggests a solution of one issue identified. It proposes an alternative design for an enhanced crutch shoe, designed to increase the versatility of the crutch while keeping it affordable and compatible with existing crutch frames. The proposed design's stability on uneven terrain was evaluated through simulation and compared to the conventional crutch for levels of ground displacement. Furthermore, the study examines the potential impact of the proposed design while estimating the cost of production and the size of its potential market. From a theoretical perspective, the differences between the existing and the proposed crutch design are considered in terms of the Technology Domestication theory by considering the role of the environment in the everyday context.

Ergonomic Design Strategy for Crutches of a Lower-limb Exoskeleton for Paraplegic Individuals: An Experimental Study

This paper presents a design strategy for crutches used to operate paraplegic exoskeletons. With Hyundai Medical Exoskeleton (H-MEX) and its controller crutch, we conducted an experiment performing a series of movements with 30 subjects followed by post-interviews. With regard to previous design of crutches, significant design issues such as operational logic and button layout were identified. We suggest HMI strategies to improve the crutch in four specific directions: simple operation, comfortable shape and arrangement, clear information feedback, and enhanced convenience. A new design has been proposed by applying the HMI strategy and will help patients more effectively by reducing burden and fatigue when using crutch.

The influence of a polymer damper on swing-through crutch gait biomechanics

Forearm crutch technology has evolved slowly compared to other assistive mobility devices, despite the highly repetitive nature of forearm crutch gait and the high incidence of overuse injuries. Using 13 able-bodied volunteers between the ages of 19 and 27, we compared the ground reaction forces of a novel crutch design featuring an elastomeric polymer situated below the handle to an identical design without a damper system and to a commercially available generic rigid forearm crutch model. There were no differences in peak vertical force or impulse between crutches. The crutch with the damper system demonstrated a significantly smaller peak braking force and impulse compared to the generic forearm crutch model. However, the crutch with the damper system demonstrated a significantly larger peak propulsive force and impulse compared to both crutch models. This finding indicates that a forearm crutch with a damper system may help to propel the crutch forward when walking on level surfaces, which could impact forward momentum.

DESIGN AND MANUFACTURE OF AN ANGLE ADJUSTABLE CRUTCH WITH KENNEDY KEY MECHANISM

A crutch is a mobility aid that transfers weight from the legs to the upper body. It has been observed that users of walking aids require double the energy than the normal gait. Users experience a lot of stress at underarm and wrist while using standard underarm or forearm crutches which is the primary reason for pain and various medical complications. Therefore, a new design of crutch has been developed which allows the user to apply his/her weight over a larger area along the forearm instead of wrist and underarm. The primary objective of the study is provide more comfort to the end user of the crutch. The modeling of the new crutch design has been done using CAD modeling package (Catia). Finite Element Analysis (FEA) of the design has been conducted using ANSYS to understand the stress behavior in the new model. The new crutch has been fabricated using aluminum alloy because of its properties like high strength to weight ratio and low density. The fabrication of the new crutch has been performed in such a way that it ensured the entire crutch can be disassembled easily thus making it easily transportable. The testing of the new crutch has been carried out using energy expenditure method to assess the comfort level of the user.

Crutch art painting in the middle age as orthopaedic heritage (Part I: the lepers, the poliomyelitis, the cripples)

Throughout time from antiquity, the major objective of crutches was to restore, as close as possible, the functional capacity formerly held by a limb deficient person. The crutch is probably the oldest tool of the orthopaedist. It is probably also the most neglected in terms of progress from antiquity until the 20th century. The aim of this paper is to give a view of the different crutches used in this period by different people and to observe the influence of this period on the progress of the design of crutches.

A single-loop deterministic method for reliability-based design optimization

Reliability-based design optimization (RBDO) is a technique used for engineering design when uncertainty is being considered. A typical RBDO problem can be formulated as a stochastic optimization model where the performance of a system is optimized and the reliability requirements are treated as constraints. One major challenge of RBDO research has been the prohibitive computational expenses. In this research, a new approximation approach, termed the single-loop deterministic method for RBDO (SLDM_RBDO), is proposed to reduce the computational effort of RBDO without sacrificing much accuracy. Based on the first order reliability method, the SLDM_RBDO method converts the probabilistic constraints to approximate deterministic constraints so that the RBDO problems can be transformed to deterministic optimization problems in one step. Three comparison experiments are conducted to show the performance of the SLDM_RBDO. In addition, a reliable forearm crutch design is studied to demonstrate the applicability of SLDM_RBDO to a real industry case.

A comparison of two elbow crutch designs on functional performance in elite football (soccer) players with amputation

This study compares different measures of performance and participant preferences using two different crutch designs with elite footballers with amputation; a traditional elbow crutch and spring-assisted crutch. Seven male international athletes were randomly assigned to one of the crutch designs. Tests of speed and agility were performed one week apart. Participants completed a questionnaire regarding perceived pain, stability, fatigue, ease of use and crutch design preferences. Participants using the traditional elbow crutch were significantly (p < 0.05) faster in all tests (Illinois agility test, 3 cone agility test and 10, 20, 40 m sprints). A significant increase in perceived exertion was detected when using spring-assisted crutches (p = 0.03). Preferences were favoured to traditional crutch design for stability, ease of use, pain, preference using for soccer and on a daily basis. The findings of this study suggest significant differences in performance and user preference between traditional crutche...

Biomechanical Evaluation of an Innovative Spring-Loaded Axillary Crutch Design

ABSTRACT We evaluated an innovative spring-loaded crutch design by comparing its performance with standard crutches through a biomechanical approach. Gait analysis was conducted for 7 male subjects under two conditions: walking with standard crutches and with spring-loaded crutches. Three-dimensional kinematic data and ground reaction force were recorded. Spatiotemporal variables, external mechanical work, and elastic energy (for spring crutches) were calculated based on recorded data. The trajectories of vertical ground reaction forces with standard crutches had two main peaks before and after mid-stance, and those with optimized spring-loaded crutches had only one main peak. The magnitude of external mechanical work was significantly higher with spring-loaded crutches than with standard crutches for all subjects, and the transferred elastic energy made an important contribution to the total external work for spring-loaded crutches. No significant differences in the spatiotemporal parameters were observed. Optimized spring-loaded crutches can efficiently propel crutch walkers and could reduce the total energy expenditure in crutch walking. Further research using optimized spring-loaded crutches with respect to energy efficiency is recommended.

Metabolic Energy Expenditure During Spring-Loaded Crutch Ambulation

Individuals using traditional axillary crutches to ambulate expend approximately twice as much energy as individuals who perform able-bodied gait. A relatively novel spring-loaded crutch now being marketed may reduce metabolic energy expenditure during crutch ambulation. This idea, however, had not yet been tested. To determine whether the novel spring-loaded crutch reduces oxygen consumption during crutch ambulation, relative to traditional-crutch ambulation. A secondary purpose was to evaluate the design for subject-perceived comfort and ease of use. Within-subject. Indoor track. 10 able-bodied men and 10 able-bodied women. The independent variable was crutch design. Each subject ambulated using 3 different crutch designs (traditional, spring-loaded, and modified spring-loaded), in a randomized order. The primary dependent variable was oxygen consumption. Secondary dependent variables were subject-perceived comfort and ease of use, as rated by the subjects using a 100-mm visual analog scale. Dependent variables were compared among the 3 crutch designs using a 1-way repeated-measures ANOVA (α = .05). Oxygen consumption during spring-loaded-crutch ambulation (17.88 ± 2.13 mL · kg⁻¹ · min⁻¹) was 6.2% greater (P = .015; effect size [ES] = .50) than during traditional axillary-crutch ambulation (16.84 ± 2.08 mL · kg⁻¹ · min⁻¹). There was no statistically significant difference (P = .068; ES = -.45) for oxygen consumption between spring-loaded-crutch ambulation and ambulation using the modified crutch (17.03 ± 1.61 mL · kg⁻¹ · min⁻¹). Subjects perceived the spring-loaded crutch to be more comfortable (P < .001; ES = .56) than the traditional crutch. There was no difference (P = .159; ES = -.09) between the spring-loaded and traditional crutches for subject-perceived ease of use. Compared with traditional axillary crutches, the novel spring-loaded crutch may be more comfortable but does not appear to benefit subjects via reduced metabolic energy expenditure.

Assessing User Experience with Crutch Use: A Review of Literature

Usability and human-product interaction experience are of great importance when evaluating the current design and future improvements of any product. This literature review examines the current research being conducted on consumer experience with crutch use and identifies key elements related to this topic. A brief overview of product conceptualization regarding crutch design is provided including reports and studies addressing medical conditions resulting from crutch use. After assistive technology and patterns of crutch use are addressed, reports of discomforts and impedances pertaining to user experience are outlined. These usability and interaction topics inform the final discussion — a proposed research study on the subject of consumer experience with crutches is described in relation to focusing on user experience with mobility-related assistive technology devices and possible crutch design interventions.

The Application of Memetic Algorithms for Forearm Crutch Design: A Case Study

Product design has normally been performed by teams, each with expertise in a specific discipline such as material, structural, and electrical systems. Traditionally, each team would use its member′s experience and knowledge to develop the design sequentially. Collaborative design decisions explore the use of optimization methods to solve the design problem incorporating a number of disciplines simultaneously. It is known that such optimized product design is superior to the design found by optimizing each discipline sequentially due to the fact that it enables the exploitation of the interactions between the disciplines. In this paper, a bi‐level decentralized framework based on Memetic Algorithm (MA) is proposed for collaborative design decision making using forearm crutch as the case. Two major decisions are considered: the weight and the strength. We introduce two design agents for each of the decisions. At the system level, one additional agent termed facilitator agent is created. Its main function is to locate the optimal solution for the system objective function which is derived from the Pareto concept. Thus to Pareto optimum for both weight and strength is obtained. It is demonstrated that the proposed model can converge to Pareto solutions.

Optimization of Spring-Loaded Crutches via Boundary Value Problem

The objective of the work is to optimize the design of spring-loaded crutches by choosing appropriate spring stiffness based on their dynamic characteristics. It was shown in the literature that ambulation with spring-loaded crutches reduces the initial impulse yielded by ambulation with standard crutches and provides a propulsion mechanism. This research not only provides a genre of the spring-loaded crutches via compliance, but also proposes an approach to optimize the stiffness of the helical spring through studying the dynamics of crutch stance. The method is developed using a boundary value problem and its solution method and is studied numerically. Experiments were carried out on four subjects in a biomechanics laboratory. It suggests that the optimized spring-loaded crutches guarantee the propulsion mechanism at the right time and right position during dynamical ambulation.

A Metabolic Evaluation Of A Novel Spring-loaded Crutch Design

A Metabolic Evaluation Of A Novel Spring-loaded Crutch Design

Biomechanical evaluation of handgrips for the design of elbow crutches

Biomechanical techniques can play a major role in the objective evaluation of technical aids performance. Little information exists regarding elbow crutch handgrip performance. This paper applies different biomechanical techniques to evaluate handgrip performance. These techniques include quantitat ive recording of pressures in the hand-handgrip interface, and subjective tests which, properly treated, provide objective information about the evolution of pain and general comfort in different parts of the hand, together with the user's opinion of different designs. The present work shows an application of biomechanical techniques to the design of a new handgrip for elbow crutches. In our example, the best alternative among four proposed designs, was determined by the user criterion comfort of use.

Heart rate evaluation of axillary and elbow crutches

The aim of this study was to compare the possible effect on heart rate in patients with a walking disability using 11 different crutch designs. Eighteen patients, over the age of 18 years, who had used crutches for a minimum of 2 weeks before the study were divided into two groups: elbow and axillary crutch users respectively. The former tested six different designs of elbow crutches and the latter five different pairs of axillary crutches. Heart rate was recorded, using a portable digital pulse monitor during a 5-min walk on the level at self-selected velocities. Walking heart rates increased between 28.6 and 58.8% compared with the resting phase. No differences were found in either heart rate or walking speed between elbow crutches. However, a significant difference (p less than 0.001) in heart rate was noted between elbow crutch users who were non-weight bearing on their injured leg compared with those who were partial-weight bearing. The Canadian axillary crutch showed the lowest increase in heart rate at comparable walking speeds compared with other axillary crutches. Prescribers should be aware that the reduced energy requirements of the Canadian crutch would benefit patients with reduced cardiorespiratory function.

Upper limb loadings of gait with crutches.

Long-term crutch users and patients with arthritis are particularly susceptible to upper limb joint degeneration during aided gait. The function of the walking aid for stability, support, and restraint/propulsion must be optimized with the upper limb loadings caused by the aids. Post-operative total hip replacement (THR) patients, tibial fracture, and paraplegic subjects using sticks and elbow crutches were analyzed in this study. Elbow and shoulder joint centers and aid orientations were monitored simultaneously in three dimensions and combined with aid forces to determine upper limb moment loadings. Three loading effects were observed: tendency for the aids to cause 1) the elbow to flex and shoulder to extend, 2) the elbow and shoulder to extend, and 3) the shoulder to abduct. Moment values of up to 0.10 Nm per body weight (BW) causing the shoulder to extend were measured, i.e., of similar magnitude to the moments at the hip in unaided gait. A modification of the elbow crutch, designed to improve medial-lateral stability, was unsuccessful in use due to wrist instability. This reinforced the requirement that crutch designs integrate the aid's function in gait with the ability of the upper limb joints to balance the applied loads.

Design and use of improved walking aids

The design of crutches and walking sticks to assist the disabled has not varied much since their original conception, some 5000 years ago. From an engineering viewpoint one must consider crutches and walking sticks as dynamic mechanical systems which alleviate a disability; they may act as supports, help the user to recover from stumbling, or transmit from the arms, the energy required to lift the feet from the ground, an action not provided by artificial ankle joints. We describe some dynamic walking aids recently developed at the Instituto de Mecánica Aplicada, and discuss their design and our experience with their use. They are adjustable in height, shock absorbing and have non-slipping tips. Specially developed aids have been designed for children; they are versatile and their use has been made psychologically attractive.