Influential factors in stability of lower-limb amputees

Effects of combining a high-intensity interval training programme with a standard programme on mobility and function in lower limb amputees

High-energy expenditure during walking is one of the most important limiting factors for lower limb amputees. Although several physical training methods have been proposed to reduce energy expenditure, little is known about the effects of high-intensity interval training in lower limb amputees. This study aimed to test the effects of a 6-week high-intensity interval training protocol in subjects with lower limb amputation on walking distance, physiological cost of walking, and functional mobility. A quasi-experimental pre and post-study included 13 subjects with lower limb amputation. They performed 12 sessions of a high-intensity interval training protocol with a frequency of 2 days/week for 6 weeks. Walking distance, physiological cost of walking, and functional mobility before and after the training protocol were assessed. Walking distance increased from 204.48 to 229.09 m (P = 0.003), physiological cost of walking decreased from 0.66 to 0.31 beats/m (P = 0.001), and functional mobility improved from 30.38 to 33.61 points (P = 0.001). High-intensity interval training improved walking distance, physiological cost of walking, and functional mobility in subjects with lower limb amputation.

Effects of tactile vibration feedback system on balance function and walking ability of a unilateral transtibial amputee with a prosthesis: A case report

RATIONALE

There is still a lack of case reports about tactile vibration feedback devices for the treatment of transtibial amputees so far. This case report aims to introduce a tactile vibration feedback device designed to improve the balance and walking function of the transtibial amputee.

PATIENT CONCERNS

The amputee was a 20-year-old man with right transtibial amputation in a car accident four years ago.

DIAGNOSE

The clinical diagnosis of him was "Right transtibial amputation," and the rehabilitation diagnosis was "Motor dysfunction (Balance function abnormality and Gait abnormality)."

INTERVENTIONS

The patient was reminded to adjust their posture in time via the tactile vibration feedback device.

OUTCOMES

The balance and walking function of the volunteer transtibial amputee was improved.

CONCLUSION

The tactile vibration feedback device has the potential to improve the balance and walking function of the transtibial amputee after installation. Potential fields that can be recommended for future research include intelligent prosthetics, feedback training, motor function, prosthetic acceptance, compliance, social communication, and the quality of life.

Sensory neuroprosthesis improves postural stability during Sensory Organization Test in lower-limb amputees

To maintain postural stability, unilateral lower-limb amputees (LLAs) heavily rely on visual and vestibular inputs, and somatosensory cues from their intact leg to compensate for missing somatosensory information from the amputated limb. When any of these resources are compromised, LLAs exhibit poor balance control compared to able-bodied individuals. We hypothesized that restoring somatosensation related to the missing limb via direct activation of the sensory nerves in the residuum would improve the standing stability of LLAs. We developed a closed-loop sensory neuroprosthesis utilizing non-penetrating multi-contact cuff electrodes implanted around the residual nerves to elicit perceptions of the location and intensity of plantar pressures under the prosthetic feet of two transtibial amputees. Effects of the sensory neuroprosthesis on balance were quantified with the Sensory Organization Test and other posturographic measures of sway. In both participants, the sensory neuroprosthesis improved equilibrium and sway when somatosensation from the intact leg and visual inputs were perturbed simultaneously. One participant also showed improvement with the sensory neuroprosthesis whenever somatosensation in the intact leg was compromised via perturbations of the platform. These observations suggest the sensory feedback elicited by neural stimulation can significantly improve the standing stability of LLAs, particularly when other sensory inputs are depleted or otherwise compromised.

Fall Prevalence and Contributors to the Likelihood of Falling in Persons With Upper Limb Loss

BACKGROUND

Arms are important for locomotor stability and preventing falls by controlling whole-body angular momentum, redirecting the body's center of mass, and providing support to arrest descent. Hence, upper limb loss (ULL) can increase fall risk. However, the prevalence of falls and factors that influence fall risk have not previously been reported for people with ULL.

OBJECTIVE

This study quantified fall prevalence in persons with ULL at or proximal to the wrist and identified clinical factors that contributed to the likelihood of falling.

DESIGN

This was a cross-sectional study.

METHODS

Factors including body and health characteristics, activity level, fall history, prosthesis use, and balance confidence were determined for persons with ULL proximal to the wrist using an online survey. Logistic regression analyses assessed the contribution of these factors to the classification of fallers (≥2 falls in previous year) and nonfallers.

RESULTS

A percentage (28.6%) of participants (n = 105) reported experiencing 2 or more falls in the past year. The regression model (R2 = 0.473) correctly classified 84.5% of cases and indicated that increased likelihood of falling was significantly influenced by reduced balance confidence, use of upper limb prostheses, and reduced physical capabilities.

LIMITATIONS

Data were collected online from a convenience sample, and fall classification was based on retrospective data.

CONCLUSIONS

Falls in persons with ULL are prevalent, suggesting that clinicians should use screening methods to identify at-risk individuals. Balance confidence, use of upper limb prostheses, and perceived physical capabilities could be useful screening metrics. Research is warranted to better understand the factors that underlie fall risk in persons with ULL and the efficacy of therapeutic interventions capable of mitigating fall risk.

Intra-arterial fibrinolysis for the management of acute ischemia on a below-knee amputation stump. Case report

Preservation of the knee joint has enormous advantages in terms of mobility and rehabilitation of an amputee. Any cause of breakdown requiring revision to an above-knee amputation is a major setback because it reduces the patient’s rehabilitative potential. We report a case of intra-arterial thrombolysis use to save a below-knee amputation stump with acute ischemia. A 56-year-old man who sought the emergency department with 1-day history of acute pain on his right below-knee stump. The angiography confirmed popliteal artery occlusion. Pharmacomechanical thrombectomy, with Aspirex (rotational catheter to restore blood flow in occluded vessel, by removing occlusion material from the vessel) and recombinant tissue plasminogen activator, was performed. After 9 years of follow-up the patient remained asymptomatic, capable of independent ambulation with prosthetic limb. Intra-arterial fibrinolysis seems to be a safe and effective treatment for cases of acutely ischemic amputation stump.

Improved Weight-Bearing Symmetry for Transfemoral Amputees During Standing Up and Sitting Down With a Powered Knee-Ankle Prosthesis

OBJECTIVE

To test a new user-modulated control strategy that enables improved control of a powered knee-ankle prosthesis during sit-to-stand and stand-to-sit movements.

DESIGN

Within-subject comparison study.

SETTING

Gait laboratory.

PARTICIPANTS

Unilateral transfemoral amputees (N=7; 4 men, 3 women) capable of community ambulation.

INTERVENTIONS

Subjects performed 10 repetitions of sit-to-stand and stand-to-sit with a powered knee-ankle prosthesis and with their prescribed passive prosthesis in a randomized order. With the powered prosthesis, knee and ankle power generation were controlled as a function of weight transferred onto the prosthesis.

MAIN OUTCOME MEASURES

Vertical ground reaction force limb asymmetry and durations of movement were compared statistically (Wilcoxon signed-rank test, α=.05).

RESULTS

For sit-to-stand, peak vertical ground reaction forces were significantly less asymmetric using the powered prosthesis (mean, 19.3%±11.8%) than the prescribed prosthesis (57.9%±13.5%; P=.018), where positive asymmetry values represented greater force through the intact limb. For stand-to-sit, peak vertical ground reaction forces were also significantly less asymmetric using the powered prosthesis (28.06%±11.6%) than the prescribed prosthesis (48.2%±16%; P=.028). Duration of movement was not significantly different between devices (sit-to-stand: P=.18; stand-to-sit: P=.063).

CONCLUSIONS

Allowing transfemoral amputees more control over the timing and rate of knee and ankle power generation enabled users to stand up and sit down with their weight distributed more equally between their lower limbs. Increased weight bearing on the prosthetic limb may make such activities of daily living easier for transfemoral amputees.

AN ASSESSMENT OF STABILITY, GAIT PERFORMANCE AND ENERGY CONSUMPTION IN INDIVIDUALS WITH TRANSFEMORAL AMPUTATION

Transfemoral amputation (TFA) results in reduced sensation, altered body image and loss of function. Energy expenditure is known to be significantly higher in individuals with TFA compared with their healthy counterparts. Kinetic and kinematics characteristics of individuals with TFA have been evaluated; however, stability during quiet standing has not been examined. This study evaluated stability, gait performance and energy consumption in individuals with TFA during standing and walking. A total of subjects (5 healthy and 5 with TFA) participated in this study. The motion of lower limb joints and the force applied on the leg were evaluated using a motion analysis system, Qualysis. Stability during standing was examined using a force plate and energy consumption during walking was evaluated based on physiological cost index (PCI). Group comparisons were made using the independent t-test. There was no significant difference in stability between subjects with TFA and normal subjects during standing. However, walking speed in subjects with TFA decreased significantly compared to normal subjects (p = 0.014). PCI of subjects with TFA was 0.525 ± 0.13 compared to 0.298 ± 0.059 beats/m in normal subjects (p < 0.05). It seems that stability in subjects with TFA was similar to their healthy counterparts. However, energy consumption was higher in the TFA group than in normal subjects, which may be due to slow walking speed. Clinicians are to be aware of these findings as they may be useful for effective management of the patients with TFA.

Postural stability characteristics of transtibial amputees wearing different prosthetic foot types when standing on various support surfaces

PURPOSE

This study aimed to evaluate the effects of prosthetic foot types on the postural stability among transtibial amputees when standing on different support surfaces.

MATERIALS AND METHODS

The postural stability of 10 transtibial amputees wearing solid ankle cushion heel (SACH) foot, single-axis (SA) foot, and energy-saving and return (ESAR) foot was assessed. Results were compared with able-bodied participants. Anterior-posterior stability index (APSI), mediolateral stability index (MLSI), and overall stability index (OSI) were measured by computed posturography in an upright stance on firm, foam, and unstable support surfaces.

RESULTS

The mean OSI score of SACH foot was significantly lower than that of an ESAR foot when the participants were standing on a compliant surface. When compared to able-bodied group, MLSI score was significantly higher for each of the prosthetic foot groups while OSI score was significantly higher for ESAR foot only in foam condition.

CONCLUSIONS

Differences between prosthetic foot types and groups (amputees versus able-bodied) can only be distinguished when individuals were standing on a compliant surface. Amputees exhibited an increased postural instability in the mediolateral direction than able-bodied individuals. Hence, the restoration of stability in the frontal plane and the enhancement of proprioception at the residual limb should be the basis of rehabilitation programs.