Assessment of Gait Patterns during Crutch Assisted Gait through Spatial and Temporal Analysis.

The use of crutches is a common method of assisting people during recovery from musculoskeletal injuries in the lower limbs. There are several different ways to walk with crutches depending on the patient's needs. The structure of crutch gaits or crutch gait patterns varies based on the delay between the aid and foot placement, the number of concurrent points of contact, and laterality. In a rehabilitation process, the prescribed pattern may differ according to the injury, the treatment and the individual's condition. Clinicians may improve diagnosis, assessment, training, and treatment by monitoring and analyzing gait patterns. This study aimed to assess and characterize four crutch walking patterns using spatial and temporal parameters obtained from the instrumented crutches. For this purpose, 27 healthy users performed four different gait patterns over multiple trials. Each trial was recorded using a portable system integrated into the crutches, which measured force, position, and acceleration. Based on the data angle, an algorithm was developed to segment the trials into gait cycles and identify gait phases. The next step was to determine the most appropriate metrics to describe each gait pattern. Several metrics were used to analyze the collected data, including force, acceleration, angle, and stride time. Among 27 participants, significant differences were found between crutch gait patterns. Through the use of these spatial and temporal parameters, promising results were obtained for monitoring assisted gait with crutches. Furthermore, the results demonstrated the possibility of using instrumented crutches as a clinical tool.

Walking with unilateral ankle-foot unloading: a comparative biomechanical analysis of three assistive devices.

BACKGROUND: Foot and ankle unloading is essential in various clinical contexts, including ulcers, tendon ruptures, and fractures. Choosing the right assistive device is crucial for functionality and recovery. Yet, research on the impact of devices beyond crutches, particularly ankle-foot orthoses (AFOs) designed to unload the ankle and foot, is limited. This study investigates the effects of three types of devices-forearm crutches, knee crutch, and AFO-on biomechanical, metabolic, and subjective parameters during walking with unilateral ankle-foot unloading. METHODS: Twenty healthy participants walked at a self-selected speed in four conditions: unassisted able-bodied gait, and using three unloading devices, namely forearm crutches, iWalk knee crutch, and ZeroG AFO. Comprehensive measurements, including motion capture, force plates, and metabolic system, were used to assess various spatiotemporal, kinematic, kinetic, and metabolic parameters. Additionally, participants provided subjective feedback through questionnaires. The conditions were compared using a within-subject crossover study design with repeated measures ANOVA. RESULTS: Significant differences were found between the three devices and able-bodied gait. Among the devices, ZeroG exhibited significantly faster walking speed and lower metabolic cost. For the weight-bearing leg, ZeroG exhibited the shortest stance phase, lowest braking forces, and hip and knee angles most similar to normal gait. However, ankle plantarflexion after push-off using ZeroG was most different from normal gait. IWalk and crutches caused significantly larger center-of-mass mediolateral and vertical fluctuations, respectively. Participants rated the ZeroG as the most stable, but more participants complained it caused excessive pressure and pain. Crutches were rated with the highest perceived exertion and lowest comfort, whereas no significant differences between ZeroG and iWalk were found for these parameters. CONCLUSIONS: Significant differences among the devices were identified across all measurements, aligning with previous studies for crutches and iWalk. ZeroG demonstrated favorable performance in most aspects, highlighting the potential of AFOs in enhancing gait rehabilitation when unloading is necessary. However, poor comfort and atypical sound-side ankle kinematics were evident with ZeroG. These findings can assist clinicians in making educated decisions about prescribing ankle-foot unloading devices and guide the design of improved devices that overcome the limitations of existing solutions.

Muscle specific declines in oxygen saturation during acute ambulation with hands-free and conventional mobility devices.

Disuse is associated with reduced muscle oxygen saturation (SmO2). Improving oxygen delivery to tissues is important for healing, preventing muscle atrophy, and reducing the risk of deep vein thrombosis. Mobility devices are used during disuse periods to ambulate and protect the injured limb. This study examined SmO2 in walking and ambulation with various mobility devices. Thirty-eight participants randomly completed four, ten-minute trials which included: (1) walking, (2) medical kneeling scooter (MKS), (3) hands-free crutch (HFC), and (4) axillary crutch (AC). During each trial, near infrared spectroscopy sensors were placed on the vastus lateralis (VL), biceps femoris (BF), and lateral gastrocnemius (LG) of the right limb. Compared to walking, all mobility devices showed a decline in SmO2 in the VL of ∼10% (mean ± SD; 75% ± 12%-65% ± 17%, P < 0.05). In the BF, SmO2 declined ∼9% in AC compared to walking (76% ± 12%-67% ± 17%, P = 0.025). In the LG, SmO2 declined in AC (64% ± 16%) compared to MKS (70% ± 15%, P = 0.005). There were no differences in LG SmO2 compared to walking (69% ± 13%) in MKS (P > 0.05) or HFC (65% ± 15%, P > 0.05). In young, healthy volunteers, the use of mobility devices altered muscle oxygenation in several muscles. AC reduced muscle oxygenation in the VL, BF, and LG; while MKS and HFC maintained BF and LG muscle oxygenation at a level consistent with ambulatory walking.

Validation of Estimators for Weight-Bearing and Shoulder Joint Loads Using Instrumented Crutches.

This research paper aimed to validate two methods for measuring loads during walking with instrumented crutches: one method to estimate partial weight-bearing on the lower limbs and another to estimate shoulder joint reactions. Currently, gait laboratories, instrumented with high-end measurement systems, are used to extract kinematic and kinetic data, but such facilities are expensive and not accessible to all patients. The proposed method uses instrumented crutches to measure ground reaction forces and does not require any motion capture devices or force platforms. The load on the lower limbs is estimated by subtracting the forces measured by the crutches from the subject's total weight. Since the model does not consider inertia contribution in dynamic conditions, the estimation improves with low walking cadence when walking with the two-point contralateral and the three-point partial weight-bearing patterns considered for the validation tests. The shoulder joint reactions are estimated using linear regression, providing accurate values for the forces but less accurate torque estimates. The crutches data are acquired and processed in real-time, allowing for immediate feedback, and the system can be used outdoors in real-world walking conditions. The validation of this method could lead to better monitoring of partial weight-bearing and shoulder joint reactions, which could improve patient outcomes and reduce complications.

Load analysis of hands and feet while using different types of crutches with various leg's weight bearing.

The study aimed to define the load on hands using various commonly used types of crutches while walking with a full load on both legs (FL), with 20 kg partial load (PL), or with the left leg wholly unloaded (UL). Twenty-six healthy subjects used crutches with ergonomic handles, with anatomic handles (wider and softer bearing surface), and arthritis crutches (horizontal supporting area for the forearm). Sensor mats between hand and handles continuously measured the load transmitted, while sensor soles in the shoes recorded the ground reaction forces simultaneously. The load on the palm and separately the radial and ulnar halves of the palm were analyzed. With arthritis crutches, significantly lower load was transferred to the hands compared to forearm crutches (FL 3% vs. 25% of body weight, PL 8% vs. 87%, UL 12% vs. 103%). The load on hands increased significantly from FL to PL and UL for both types of crutches. The ipsilateral left hand had to bear significantly more load than the right hand. However, the feet's time-ground reaction curves showed more irregularities, and PL on the left leg was significantly higher with arthritis crutches. Anatomic handles reduced the load on the ulnar half of the palm (FL 3% vs. 5%, PL 13% vs. 18%, UL 17% vs. 23%); the radial half of the palm had a similar load to bear with both types of handles (11/11%, 31/32%, 34/35%). Arthritis crutches allow unburdening hands at the expense of gait stability. Anatomic handles reduce the load on the Guyon's canal.

Functional, Spiroergometric, and Subjective Comparisons Between Forearm Crutches and Hands-Free Single Crutches in a Crossover Study.

Background: Following below-knee surgery, the optimal medical mobility device remains controversial as adequate nonweightbearing of the operated extremity is critical to ensure successful healing. The use of forearm crutches (FACs) is well established but requires using both upper extremities. The hands-free single orthosis (HFSO) is an alternative that spares the upper extremities. This pilot study compared functional, spiroergometric, and subjective parameters between HFSO and FAC. Methods: Ten healthy (5 females, 5 males) participants were asked to use HFSOs and FACs in a randomized order. Five functional tests were performed: climbing stairs (CS), an L-shaped indoor course (IC), an outdoor course (OC), a 10-meter walk test (10MWT), and a 6-minute walk test (6MWT). Tripping events were counted while performing IC, OC, and 6MWT. Spiroergometric measurements consisted of a 2-step treadmill test with speeds of 1.5 and 2 km/h, each for 3 minutes. Lastly, a VAS questionnaire was completed to collect data regarding comfort, safety, pain, and recommendations. Results: Significant differences between both aids were observed in CS and IC (HFSO: 29.3 seconds; FAC: 26.1 seconds, P < .03; and HFSO: 33.2 seconds, FAC: 18 seconds, P < .001, respectively). The other functional tests showed no significant differences. The trip events were not significantly different between the use of the 2 aids. Spiroergometric tests showed significant differences regarding heart rate (HFSO: 131.1 bpm at 1.5 km/h and 131 bpm at 2 km/h; FAC: 148.1 bpm at 1.5 km/h and 161.8 bpm at 2 km/h) and oxygen consumption (HFSO: 15.4 mL/min/kg at 1.5 km/h and 16 mL/min/kg at 2 km/h; FAC: 18.3 mL/min/kg at 1.5 km/h and 21.9 mL/min/kg at 2 km/h) at both speeds (all P < .01). In addition, significantly different ratings regarding the items comfort, pain, and recommendation were recorded. Both aids were equally rated for safety. Conclusion: HFSOs may be an alternative to FACs, especially in activities that require physical stamina. Further prospective studies in patients with below-knee surgical intervention concerning everyday clinical use would be interesting. Level of Evidence: Level IV pilot-study.

mCrutch: A Novel m-Health Approach Supporting Continuity of Care.

This paper reports the architecture of a low-cost smart crutches system for mobile health applications. The prototype is based on a set of sensorized crutches connected to a custom Android application. Crutches were instrumented with a 6-axis inertial measurement unit, a uniaxial load cell, WiFi connectivity, and a microcontroller for data collection and processing. Crutch orientation and applied force were calibrated with a motion capture system and a force platform. Data are processed and visualized in real-time on the Android smartphone and are stored on the local memory for further offline analysis. The prototype's architecture is reported along with the post-calibration accuracy for estimating crutch orientation (5° RMSE in dynamic conditions) and applied force (10 N RMSE). The system is a mobile-health platform enabling the design and development of real-time biofeedback applications and continuity of care scenarios, such as telemonitoring and telerehabilitation.

Energy Expenditure and Substrate Utilization with Hands-Free Crutches Compared to Conventional Lower-Extremity Injury Mobility Devices.

Background: A Hands-Free crutch (HFC) is a relatively new device that can be used during the nonweightbearing period to increase mobility. The primary aim of this investigation was to examine aerobic oxygen consumption (V.o2) and substrate utilization with HFC compared to conventional ambulation devices as well as normal ambulation. A secondary purpose was to quantify perceived exertion, pain, and performance during each ambulation condition. Methods: Forty participants completed 4 separate 10-minute ambulation conditions around a rectangular course. The order of the ambulation conditions was randomized and consisted of (1) walking, (2) medical knee scooter (MKS), (3) HFC, and (4) axillary crutch (AC). Indirect calorimetry was used to determine V.o2 and the respiratory exchange ratio (RER), an indicator of substrate utilization. Perceived exertion and pain were also assessed using questionnaires. Results: All mobility devices significantly elevated V.o2 (+35%) compared to walking (13.14 ± 1.70 mL/kg/min; P < .001). AC had significantly greater V.o2 requirements (20.26 ± 2.62 mL/kg/min) compared to both the MKS (15.28 ± 2.29 mL/kg/min; P < .001) and HFC (15.88 ± 2.03 mL/kg/min; P < .001). There was no difference in average V.o2 between MKS and HFC (P = .368). Compared to walking (0.78 ± 0.43), RER was significantly elevated in MKS (0.81 ± 0.05, P < .001) and AC (0.84 ± 0.06, P < .001), but not in HFC (0.79 ± 0.04, P = .350). RPE and pain were elevated in all ambulatory conditions (all P values <.001). Pain was significantly greater in AC compared with MKS (P < .001) and HFC (P < .001). Conclusion: HFC and MKS share similar V.o2 requirements over a 10-minute ambulation interval and are below those needed in AC. Substrate utilization in HFC was similar to regular walking with a greater reliance on lipid utilization for energy as evidenced by a lower RER. Exertion and pain scores were the most tolerable in HFC and MKS. Level of Evidence: Level II, prospective comparative study.

Using crutches during walking possibly reduces gait imagery accuracy among healthy young and older adults.

[Purpose] Although crutches are widely used in the field of rehabilitation to improve gait performance, patients usually have difficulties using them, and this may increase their risks for falls. This study aimed to define the accuracy of gait imagery during walking with and without crutches, in healthy young and older adults, using the mental chronometry method. [Participants and Methods] Overall, 99 healthy young (mean age, 20.2 ± 1.0 years) and 39 healthy older adults (mean age, 71.3 ± 2.9 years) performed the imagery and execution tasks, which involved walking through a distance of 10 meters both with and without crutches. Using the mental chronometry method, the accuracy of the motor imagery was defined as the difference between the imagery time and the actual execution time. Two-way analysis of variance and one-sample t-tests were performed to evaluate the accuracy of the gait imagery. [Results] Both the young and older adults significantly overestimated their gait speeds when using crutches; the overestimation was larger among the older adults. [Conclusion] The overestimations indicate that participants estimated their gait speeds with crutches to be faster than their actual speeds. Therefore, using crutches decreased the accuracy of gait imagery and might therefore increase an individual's risk of falling during walking.

Versatile GCH Control Software for Correction of Loads Applied to Forearm Crutches During Gait Recovery Through Technological Feedback: Development and Implementation Study.

BACKGROUND: Measuring weight bearing is an essential aspect of clinical care for lower limb injuries such as sprains or meniscopathy surgeries. This care often involves the use of forearm crutches for partial loads progressing to full loads. Therefore, feasible methods of load monitoring for daily clinical use are needed. OBJECTIVE: The main objective of this study was to design an innovative multifunctional desktop load-measuring software that complements GCH System 2.0-instrumented forearm crutches and monitors the applied loads, displaying real-time graphical and numerical information, and enabling the correction of inaccuracies through feedback technology during assisted gait. The secondary objective was to perform a preliminary implementation trial. METHODS: The software was designed for indoor use (clinics/laboratories). This software translates the crutch sensor signal in millivolts into force units, records and analyzes data (10-80 Hz), and provides real-time effective curves of the loads exerted on crutches. It covers numerous types of extrinsic feedback, including visual, acoustic (verbal/beeps), concurrent, terminal, and descriptive feedback, and includes a clinical and research use database. An observational descriptive pilot study was performed with 10 healthy subjects experienced in bilateral assisted gait. The Wilcoxon matched-pairs signed-rank test was used to evaluate the load accuracy evolution of each subject (ie, changes in the loads exerted on crutches for each support) among various walks, which was interpreted at the 95% confidence level. RESULTS: GCH Control Software was developed as a multifunctional desktop tool complementing GCH System 2.0-instrumented forearm crutches. The pilot implementation of the feedback mechanism observed 96/100 load errors at baseline (walk 0, no feedback) with 7/10 subjects exhibiting crutch overloading. Errors ranged from 61.09% to 203.98%, demonstrating heterogeneity. The double-bar feedback found 54/100 errors in walk 1, 28/100 in walk 2, and 14/100 in walk 3. The first walk with double-bar feedback (walk 1) began with errors similar to the baseline walk, generally followed by attempts at correction. The Wilcoxon matched-pairs signed-rank test used to evaluate each subject's progress showed that all participants steadily improved the accuracy of the loads applied to the crutches. In particular, Subject 9 required extra feedback with two single-bar walks to focus on the total load. The participants also corrected the load balance between crutches and fluency errors. Three subjects made one error of load balance and one subject made six fluctuation errors during the three double-bar walks. The latter subject performed additional feedback with two balance-bar walks to focus on the load balance. CONCLUSIONS: GCH Control Software proved to be useful for monitoring the loads exerted on forearm crutches, providing a variety of feedback for correcting load accuracy, load balance between crutches, and fluency. The findings of the complementary implementation were satisfactory, although clinical trials with larger samples are needed to assess the efficacy of the different feedback mechanisms and to select the best alternatives in each case.

Aneurisma de arteria braquial inducido por el uso de muleta / Crutch-induced brachial artery aneurysm

Introducción: el uso de muletas de forma prolongada como desencadenante de aneurisma de arteria braquial es raro pero potencialmente vital. Caso clínico: presentamos a una paciente de 84 años, con historia de poliomielitis y uso prolongado de muleta en brazo derecho. Se diagnostica de isquemia crítica secundaria a oclusión de aneurisma de arteria braquial y lesiones por embolización distal. A pesar de realizarse injerto venoso, la paciente presenta mala evolución con amputación de antebrazo. Discusión: es de vital importancia el reconocimiento y tratamiento de esta patología.(AU)

Introduction: the prolonged use of crutches resulting in a brachial aneurysm is rare but potentially vital. Case report: we present an 84-year-old patient with a history of poliomyelitis and prolonged use of a crutch in her right arm. She was diagnosed with critical ischemia secondary to occlusion of brachial artery aneurysm and distal embolization lesions. Despite having performed a venous graft, the patient presented a poor evolution which resulted in a forearm amputation. Discussion: it's of vital importance to recognize and treat this pathology.(AU)

Load Auditory Feedback Boosts Crutch Usage in Subjects With Central Nervous System Lesions: A Pilot Study.

Background: Crutches are the most common walking aids prescribed to improve mobility in subjects with central nervous system (CNS) lesions. To increase adherence to the appropriate level of crutch usage, providing load-related auditory feedback (aFB) may be a useful approach. We sensorized forearm crutches and developed a custom software to provide aFB information to both user and physical therapist (PhT). Aim: Evaluate aFB effects on load control during gait by a self-controlled case series trial. Methods: A single experimental session was conducted enrolling 12 CNS lesioned participants. Load on crutch was recorded during 10 Meter Walk Test performed with and without aFB. In both cases, crutch load data, and gait speed were recorded. Usability and satisfaction questionnaires were administered to participants and PhTs involved. Results: Reliable data were obtained from eight participants. Results showed that compared to the no FB condition, aFB yielded a significant reduction in the mean load on the crutches during gait (p = 0.001). The FB did not influence gait speed or fatigue (p > 0.05). The experience questionnaire data indicated a positive experience regarding the use of aFB from both participants' and PhTs' perspectives. Conclusion: aFB significantly improves compliance with crutch use and does not affect gait speed or fatigue by improving the load placed on crutches. The FB is perceived by users as helpful, safe, and easy to learn, and does not interfere with attention or concentration while walking. Furthermore, the PhTs consider the system to be useful, easy to learn and reliable.

The utility of upper limb loading device in determining optimal walking ability in ambulatory individuals with spinal cord injury.

BACKGROUND: Walking devices are frequently prescribed for many individuals, including those with spinal cord injury (SCI), to promote their independence. However, without proper screening and follow-up care, the individuals may continue using the same device when their conditions have progressed, that may possibly worsen their walking ability. OBJECTIVE: This study developed an upper limb loading device (ULLD), and assessed the possibility of using the tool to determine the optimal walking ability of ambulatory participants with SCI who used a walking device daily ( n = 49 ). METHODS: All participants were assessed for their optimal walking ability, i.e., the ability of walking with the least support device or no device as they could do safely and confidently. The participants were also assessed for their amount of weight-bearing on the upper limbs or upper limb loading while walking, amount of weight-bearing on the lower limbs or lower limb loading while stepping of the other leg, and walking performance. RESULTS: The findings indicated that approximately one third of the participants (31%) could progress their walking ability from their current ability, whereby four participants could even walk without a walking device. The amount of upper limb loading while walking, lower limb loading ability, and walking performance were significantly different among the groups of optimal walking ability ( p < 0 . 05 ). Furthermore, the amount of upper limb loading showed negative correlation to the amount of lower limb loading and walking performance ( ρ =- 0 . 351 to - 0.493, p < 0 . 05 ). CONCLUSION: The findings suggest the potential benefit of using the upper limb loading device and the amount of upper limb loading for walking device prescription, and monitoring the change of walking ability among ambulatory individuals with SCI.

Assessing Stability of Crutch Users by Non-Contact Methods.

Enhancing gait stability in people who use crutches is paramount for their health. With the significant difference in gait compared to users who do not require an assistive device, the use of standard gait analysis tools to measure movement for temporary crush users and physically disabled people proves to be more challenging. In this paper, a novel approach based on video analysis is proposed as non-contact low-cost solution to the more expensive alternative with the data collected from processed videos, two values are calculated: the Signal to Noise Ratio (SNR) of acceleration, and the Signal to Noise Ratio of the jerk (time derivative of acceleration), to assess the user's stability while they walk with crutches. The adopted methodology has been tested on a total of 10 participants. Five are temporary users of assistive devices with one being a long-term user and the other four novice users, and five are disabled participants who use those assistive devices permanently. Preliminary results show differences between novice users, long-term users, and physically disabled users. The approach is promising and could improve the assessment of crutch user stability, allowing for the correction of gait for individuals while using an inexpensive non-contact setup and preventing unnecessary falls.

Bilateral Brachial Artery Aneurysms with Distal Embolisms in a Patient with Prolonged Crutch Compression.

Chronic axillary crutch use may lead to axillary or brachial artery aneurysms and associated axillobrachial thromboembolic complications. Most of these aneurysms remain asymptomatic and undiagnosed until a complication occurs. Early diagnosis and appropriate surgical management of the aneurysms is required for a favorable outcome. We report a case of bilateral brachial artery aneurysms with left radial and ulnar artery embolisms in a patient who had been using crutches for 33 years due to a congenital skeletal anomaly.

Changes to stance limb peak, cumulative, and regional plantar foot forces among normal walking and three mobility aids in healthy older adults.

BACKGROUND: Mobility aids are commonly prescribed to offload an injured lower extremity. Device selection may impact stance foot loading patterns and foot health in clinical populations at risk of foot ulceration. RESEARCH QUESTIONS: Two questions motivated this study: How does device selection influence peak plantar and regional (rearfoot, mid foot and forefoot) foot forces on the stance foot? Does device selection influence peak, cumulative, and regional plantar forces within a 200 m walking trial? METHODS: Twenty-one older adults walked 200 m at self-selected pace in four randomized conditions for this prospective crossover study. Participants used a walker, crutches, wheeled knee walker (WKW), and no assistive device (control condition). Plantar forces were measured using a wireless in-shoe system (Loadsol, Novel Inc., St. Paul, MN). Repeated measures analyses of variance were used to determine differences in peak and cumulative total and regional forces among walking conditions. Paired sample t-tests compared forces during first and last 30 s epochs of each condition to determine device influence over time. RESULTS: The WKW reduced peak net forces by 0.29 and 0.35 bodyweight (BW) when compared to the walker or control condition with similar trends in all foot regions. Crutch use had similar peak forces as control. There were no differences in the number of steps taken within devices comparing first and last epochs. Crutches had a 0.04 and 0.07 BW increase in peak net and forefoot forces during the last epoch. Walker use had 66.44 BW lower cumulative forefoot forces in the last epoch. SIGNIFICANCE: Crutches had similar stance foot loading as normal walking while a walker lowered forefoot forces at the expense of increased steps. A WKW may be the best choice to 'protect' tissues in the stance foot from exposure to peak and cumulative forces in the forefoot region.

Estimating upper extremity joint loads of persons with spinal cord injury walking with a lower extremity powered exoskeleton and forearm crutches.

Lower extremity powered exoskeletons with crutch support can provide upright mobility to persons with complete spinal cord injury (SCI); however, crutch use for balance and weight transfer may increase upper extremity (UE) joint loads and injury risk. This research presented the first exoskeleton-human musculoskeletal model to estimate upper extremity biomechanics, driven by 3D motion data of persons with complete SCI walking with an exoskeleton and crutch assistance. Forearm crutches instrumented with strain gauges, force plates, and a 3D motion capture system were used to collect kinematic and kinetic data from five persons with complete SCI while walking with the ARKE exoskeleton. Model output estimated participant upper extremity kinematics, kinetics, and crutch forces. Compared to inverse dynamic biomechanical crutch model studies of persons with incomplete SCI, exoskeleton users walked with more anterior trunk tilt and twice the shoulder flexion angle. Anterior tilt increased forces and moments at the crutch, shoulder, and elbow. Crutch floor contact periods were 30-40% longer, resulting in upper extremity joint impulses 5 to 12 times greater than previously reported. Reducing UE joint loading is important to reduce overuse injuries associated with ambulatory assistive devices. Incorporating a variable assist ankle joint or more experience with exoskeleton walking may reduce UE joint loads, and minimise injury risk. Study outcomes provide a quantitative understanding of UE dynamics during exoskeleton walking that can be used to improve device design, training, and rehabilitation.

Comparison of Lower Extremity EMG Muscle Testing With Hands-Free Single Crutch vs Standard Axillary Crutches.

BACKGROUND: In order to maintain nonweightbearing restrictions of the lower extremity, an assistive device must be utilized. Currently most devices require the restricted limb to be held in a static position while the contralateral extremity provides forward propulsion. Atrophy and disuse conditions ensue rapidly, slowing healing and prolonging recovery. A hands-free single crutch (HFSC) utilizes both lower extremities, potentially reducing atrophy. The purpose of this study was to examine the electromyographic (EMG) differences between an HFSC and standard axillary crutches (SAC). METHODS: A prospective, crossover study was performed using 21 healthy volunteers from an active duty foot and ankle clinic. Demographic data were obtained and then subjects were fitted with an HFSC and SAC. Wireless surface EMG sensors were applied to the belly of the rectus femoris (RF), vastus lateralis (VL), lateral gastrocnemius (LG), and the gluteus maximus (GM) by a board-certified orthopedic surgeon. Subjects then ambulated at a self-selected velocity for 30 m while 15 seconds of the gait cycle were recorded for each device. Mean muscle activity and the maximum voluntary isometric contraction (MVIC) were recorded. RESULTS: The RF, GM, and LG showed significantly increased levels of muscle activity while using the HFSC compared to SAC (respectively P = .05, P = .03, P = .03). The VL did not show significantly higher muscle activity while using the HFSC (P = .051). The RF, GM, and VL showed statistically significant higher MVIC percentages while using the HFSC compared with SAC (respectively P = .005, P = .005, P = .013). The LG did not show significantly higher MVIC percentage while using the HFSC (P = .076). CONCLUSION: The HFSC subjects demonstrated increased muscle recruitment and intensity while maintaining cyclic contractions consistent with bipedal gait pattern. SAC demonstrated less recruitment and intensity with an isometric pattern regardless of the phase of gait. CLINICAL RELEVANCE: Muscle atrophy following lower extremity immobilization.

Patient Preference and Physical Demand for Hands-Free Single Crutch vs Standard Axillary Crutches in Foot and Ankle Patients.

BACKGROUND: Weightbearing restrictions following foot and ankle surgery require the use of appropriate assistive devices for nonweightbearing ambulation during the recovery period. Selecting an appropriate assistive device that safely optimizes mobility and participation in daily activities is important to patient compliance and satisfaction. The purpose of this study was to compare physiologic demand, perceived exertion, and patient preference between a hands-free single crutch (HFSC) and standard axillary crutches (SACs) in foot and ankle patients. METHODS: Using 44 preoperative orthopedic foot and ankle patients who had a mean age of 32 (19-51) years, a prospective, randomized, crossover study was performed. The sample consisted of 35 males and 9 females. The mean body mass index (BMI) was 26 (19-36), the mean height was 1.7 m, and the mean weight was 82 kg. Patient data and preactivity heart rate were recorded for all patients, who were then randomized to either an HFSC or SACs. Each patient was randomly assigned to the device they would utilize first using a random number generator. They then crossed over to the other device after vitals returned to within 10% of their baseline heart rate. Every subject completed a 6-minute walk test (6MWT) using both assistive devices in a crossover manner. Immediately following each 6MWT, postactivity heart rate, self-selected walking velocity (SSWV), perceived exertion using the OMNI Rating of Perceived Exertion (OMNI-RPE), and perceived dyspnea using the Modified Borg Dyspnea Scale were obtained. After completing both 6MWTs, patients were asked which assistive device they preferred the most. RESULTS: The HFSC was preferred by 86% of patients. Significantly lower dyspnea scores (2.8 vs 5.3; P < .001), fatigue scores (2.4 vs 5.5; P < .001), preactivity and postactivity change in heart rate (28 vs 46 bpm; P < .001), and mean postactivity heart rate (107 vs 122 bpm; P < .001) were found using the HFSC compared with the SACs. The SAC group trended toward a higher SSWV (0.8 vs 0.77 m/s; P = .08). Those with a BMI greater than 25 also preferred iWALK over SACs (P < .05). Neither group had any falls. Sixty-eight percent of patients complained of axillary/hand pain with the SACs, while 7% complained of proximal leg strap discomfort with the HFSC. CONCLUSION: The results of the current study in our relatively healthy cohort found that foot and ankle patients who were nonweightbearing preferred the HFSC over SACs. They experienced less physiologic demand as well as discomfort and perceived less exertion when using the HFSC compared with SACs. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Influence of the load exerted over a forearm crutch in spatiotemporal step parameters during assisted gait: pilot study.

BACKGROUND: Assisted gait with forearm crutches is frequently performed during the recovery of musculoskeletal injuries of the lower limb. The amount of body weight applied to the crutch or crutches depends on the pathology and the treatment phase. The transition from assisted gait with two crutches to a single crutch is usually recommended when the subject is able to load the 50% of the body weight upon the affected member. An altered assisted gait will cause biomechanic alterations and, therefore, longer treatments and relapses. The aim of this study was to analyze the influence of 10, 25 and 50% of body weight applied to a forearm crutch during a unilateral assisted gait in the spatial and temporal step parameters to determine the load that produces alterations in gait biomechanics and the load that does not. METHODS: Eleven healthy subjects performed normal gait (NG) and assisted gait with a forearm crutch, in which the applied loads were: comfortable (C), 25 and 50% of their body weight. Vicon System was employed for gait recording. GCH System 2.0 and GCH Control Software 1.0 controlled the loads. The variables were: step length, step period, velocity, step width and step angle. Friedman test compared all the gait modalities: NG and the different loads. Wilcoxon signed-rank test analyzed ipsilateral and contralateral step parameters to the crutch globally and for each subject. RESULTS: Friedman test showed significant differences between NG, C, 25 and 50%, especially for step period and velocity. Wilcoxon test had significant differences only in 4 of the 20 general comparisons between ipsilateral and contralateral steps to the crutch. In the analysis by subjects, step length, step period and velocity showed 79/132, 110/132 and 58/66 significant differences, respectively. CONCLUSIONS: The increase in the load exerted over a forearm crutch produced an increase in the step period, accompanied by a reduction of step length and gait velocity. Step width and step angle were not modified. The unloading of 25 and 50% of body weight on a single crutch is incorrect from the biomechanical point of view. Two crutches should be employed when the body weight to unload exceeds 10%.