Influence of hybrid assistive limb gait training on spatial muscle activation patterns in spinal muscular atrophy type III.

Background: Despite the potential benefits, the effects of Hybrid Assistive Limb (HAL) gait training on changes in neuromuscular activation that accompany functional gains in individuals with spinal muscular atrophy (SMA) type III is not well known. In this article, we quantify the effects of HAL gait training on spatial muscle activity patterns in a patient with SMA type III using multi-channel surface electromyography (SEMG). Methods: A 21-years old male (168 cm, 47.8 kg) with spinal muscular atrophy type III, when diagnosed at 18-years old by genetic screening, participated in this case study. Although he presented with forearm distal muscle weakness, atrophy of the intrinsic muscles of the hand, and neuromuscular fatigue, his activities of daily living is independent. The patient underwent a separate, single 33-minute session of both HAL and treadmill gait training. To evaluate the coefficient of variation (CoV) of force and alterations in the SEMG spatial distribution patterns, modified entropy and CoV of root mean square (RMS) were calculated from the vastus lateralis (VL) muscle before and after the intervention of HAL and treadmill gait training. Each training session was separated by a period of one month to avoid cross-over effects. Results: There was a greater decrease in the ΔCoV of force and an increase in the magnitude of whole VL muscle activation from pre-intervention to post-intervention with the HAL gait training as compared to the treadmill gait training. In response to only HAL gait training, the CoV of RMS was higher, and the modified entropy was lower post-intervention than pre-intervention. Conclusions: Our results support the notion that HAL gait training has a positive benefit on motor output not only in the magnitude of SEMG generated but also the patterns of neural activation.

The Effect of Simultaneous Antigravity Treadmill Training and Electrical Muscle Stimulation After Total Hip Arthroplasty: Short Follow-Up Time.

OBJECTIVE: To assess the effectiveness of our devised hybrid physiotherapy regime using an anti-gravity treadmill and a low-frequency electrical stimulation device, as measured in patients with hip osteoarthritis after total hip arthroplasty (THA). METHODS: The outcomes of the postoperative rehabilitation in 44 patients who underwent THA for hip osteoarthritis were retrospectively examined. The conventional group (n=22) underwent the postoperative rehabilitation according to our protocol, while the hybrid group (n=22) underwent the same training, along with training on an anti-gravity treadmill and training using a low-frequency therapeutic device. The outcome measures were recorded and reviewed with the Numerical Rating Scale for pain, which rates pain on an 11-point scale from 0 to 10, surgical side knee joint extension force, 10-m walking test, Timed Up and Go test, and the 6-minute walking distance (6MD). The outcome measurement was taken 2 weeks after conducting pre-operation and antigravity treadmill training and electrical muscle stimulation, and compared the respective results. RESULTS: At the timeframe of 2 weeks from the surgery after conducting a devised hybrid physiotherapy, the values of knee extension muscle strength and 6MD were not worse in the hybrid group than conventional group. In the evaluation at 2 weeks after surgery, the knee extension muscle strength and 6MD values significantly decreased compared with the preoperative values only in the conventional group. CONCLUSION: Lower limb muscular strength and endurance were maintained in the hybrid group, which suggested that hybrid physiotherapy could maintain physical functions early after THA operation.

The Relationship between Knee Biomechanics and Clinical Assessments in ACl Deficient Patients.

The purpose of this study was to clarify the relationship between knee biomechanics and clinical assessments in ACL deficient patients. Subjects included 22 patients with unilateral ACL rupture and 22 healthy controls. Knee kinematics and kinetics during walking and running were examined using a 3-dimensional motion analysis system. The passive knee joint laxity, range of motion of knee joint, and knee muscle strength were also measured. Correlations between the knee kinematic and kinetic data and clinical assessments were evaluated. In the ACL deficient patients, there were no significant relationships between tibial translation during walking and running and passive knee joint laxity. The correlations between knee kinematics and kinetics and range of motion of knee joint were also not significant. Additionally, there were no significant correlations between knee kinematics during walking and knee muscle strength. However, there were several significant correlations between knee kinematics during running and knee muscle strength. The results demonstrate the importance of knee muscle strength for knee kinematics and kinetics during running in ACL deficient patients. Patients with stronger knee muscle strength may demonstrate more nearly normal knee joint movement during dynamic activities such as running.

Spatial electromyography distribution pattern of the vastus lateralis muscle during ramp up contractions in Parkinson's disease patients.

Parkinson's disease (PD) related decreases in muscle strength may result from both central and peripheral factors. However, the effect of PD on the neuromuscular system, such as motor unit activation properties, remains unclear. The purpose of the present study was to compare the spatial distribution pattern of electromyographic activity during sustained contractions in healthy subjects and PD patients. Twenty-five female PD patients and 25 healthy age-matched female control subjects performed ramp submaximal contractions during an isometric knee extension from 20% to 80% of the maximal voluntary contraction (MVC). To evaluate alterations in the spatial electromyography (EMG) potential distribution, normalized root mean square (RMS), modified entropy, coefficient of variation, and correlation coefficients were calculated from multi-channel surface electromyography at 10% force increments. The comparison between PD and healthy subjects revealed that, during increased force exertions, PD patients exhibited less change in normalized RMS, modified entropy, coefficient of variation, and pattern of spatial EMG distribution. These data showed that the heterogeneity and the changes in the activation pattern are smaller in the PD patients than in healthy subjects. This finding may be associated with central adaptation and/or peripheral changes in PD patients.

Sex differences in variances of multi-channel surface electromyography distribution of the vastus lateralis muscle during isometric knee extension in young adults.

PURPOSE: The aim of the present study was to compare spatial electromyographic potential distribution during force production between healthy young female and male using multi-channel surface electromyography (multi-SEMG). METHODS: Thirty healthy subjects (15 females) performed sustained isometric knee extension at 10% maximal voluntary contraction (MVC) task for 120 s. Multi-SEMG signals from the vastus lateralis muscle were detected and the modified entropy, coefficient of variation (CV), and correlation coefficient determined. RESULTS: The modified entropy and CV showed significant interaction and difference between females and males at all time points during the 10% MVC task. The correlation coefficient in females was significantly lower at 90 and 120 s than that of males. CONCLUSIONS: The multi-SEMG potential distribution pattern in females showed more varied motor unit recruitment during sustained low-intensity isometric contraction than that of males. Variations in motor unit recruitment may result from recruitment and/or de-recruitment of motor units.

Deviation in the recovery of the lower limb and respiratory muscles of patients with polymyositis: a preliminary clinical study.

[Purpose] The purposes of this study were to quantify the serial changes in lower limb and respiratory muscle strengths and to evaluate the acute effects of physiotherapy in polymyositis patients. [Subjects and Methods] Five patients (57.6 ± 9.0 years, 50 to 72; four females) received physiotherapy five days a week for four weeks. The lower limb and respiratory muscle strength, the % vital capacity, and the Barthel index were evaluated at baseline and after the intervention. [Results] The patient's symptoms and creatine kinase values did not change, and after four weeks, all of the patients exhibited significantly increased outcomes compared with the baseline. However, the inspiratory muscle strength of the patients presented smaller improvements than the expiratory muscle strength. [Conclusion] Differential changes in inspiratory and expiratory muscle strength were observed following physiotherapy, and an unbalanced muscle distribution may explain the pathological and therapeutic effects.

Knee biomechanics during walking in recurrent lateral patellar dislocation are normalized by 1 year after medial patellofemoral ligament reconstruction.

PURPOSE: Gait kinematics and kinetics of the knee before and after medial patellofemoral ligament (MPFL) reconstruction in patients with recurrent lateral patellar dislocation (RPD) are unknown. The purpose of this study was to measure knee kinematics and kinetics during gait before and 1 year after anatomical MPFL reconstruction in patients with RPD and compare the results to healthy individuals. METHODS: Eleven RPD patients were treated using an anatomical MPFL reconstruction procedure. Gait analysis was conducted before and at 3, 6, and 12 months after surgery. For comparison, 15 healthy volunteers with no history of orthopaedic problems in their lower limbs were included as the control group. Knee kinematics and kinetics were analysed during gait. RESULTS: Before surgery, the internal knee extension moment in RPD patients was significantly lower than in controls (P = 0.025). At 3 months post-operatively, there was an additional decrease in knee extension moment compared to before surgery, and so it was still significantly lower than in the control group (P < 0.01). One year post-operatively, knee extension moment in the RPD group was significantly increased compared to 3 months post-operatively (P < 0.01). The knee flexion angle in the early stance phase in the RPD group at 3 months post-operatively was significantly lower than that of controls (P < 0.01). Knee kinematics and kinetics were similar to that of controls 1 year after surgery. CONCLUSION: Initially, RPD patients had lower knee extension moments during gait compared with controls, but by 1 year after MPFL reconstruction, knee kinematics and kinetics of gait in the RPD patients had returned to normal. These observations indicate that MPFL reconstruction may help to delay prospective knee OA as long as possible by restoring the conformation of the patellofemoral joint and gait biomechanics by surgery.

Courses of change in knee adduction moment and lateral thrust differ up to 1 year after TKA.

PURPOSE: In total knee arthroplasty (TKA), dynamic knee loading may loosen the artificial joint and bone or cause polyethylene wear after prolonged use. TKA decreases knee adduction moment at 6 months, but this effect is lost by 1 year post-operatively. However, lateral thrust after TKA has not been clarified. We hypothesized that like knee adduction moment, lateral thrust would return to baseline levels by 1 year post-operatively. METHODS: Participants were 15 patients who underwent TKA for medial knee OA. Japanese Orthopaedic Association (JOA) score, numeric rating scale, and gait analysis (measurement of peak knee adduction moment, knee varus angle at peak knee adduction moment, lateral thrust, and gait speed) were performed preoperatively (baseline) and 3 weeks, 3 and 6 months, and 1 year post-operatively. RESULTS: JOA score improved from 55 ± 9.8 to 78 ± 12.1 at 1 year post-operatively, and pain decreased significantly from baseline at each follow-up (p < 0.001). Significant increases in gait speed were observed at 6 months and 1 year (p < 0.001). Peak knee adduction moment during stance phase was significantly lower at 3 weeks, 3 months, and 6 months compared to baseline (p < 0.05), but no significant changes were seen at 1 year. Knee varus at peak knee adduction moment did not differ significantly between any measurement points, while lateral thrust was decreased at 6 months and 1 year compared to baseline (p < 0.05). CONCLUSIONS: Temporal courses of changes up to 1 year after TKA differed between knee adduction moment and lateral thrust, so our hypothesis was rejected. LEVEL OF EVIDENCE: IV.

Posterior tibial displacement in the PCL-deficient knee is reduced compared to the normal knee during gait.

PURPOSE: Most individuals with an isolated posterior cruciate ligament (PCL) injury do not complain of disability even if posterior instability is objectively revealed by a static physical examination, such as the posterior drawer test. This suggests it is insufficient to only evaluate posterior instability under static conditions. Therefore, we have investigated the effect of isolated PCL injury on the detailed kinematics of the knee in a dynamic environment such as during gait. METHODS: Eight unilateral PCL-deficient males and eight healthy control volunteers participated in this study. Isolated PCL injury was diagnosed by clinical examination. Stress X-ray imaging showed an average side-to-side difference of 12.7 ± 3.5 mm. Knee kinematics including anteroposterior tibial displacement were analysed during walking using the point cluster technique. RESULTS: Posterior tibial displacement from initial contact was significantly smaller during 9-22 % of the gait cycle by an average of 0.4 cm in the PCL group, compared to controls. In the PCL-deficient knee, the external rotational angle increased by an average of 3.3° at the loading response during 3-11 % of the gait cycle and the varus angle from initial contact increased by an average of 2.0° during 28-52 % of the gait cycle, compared to controls. CONCLUSIONS: Dynamic changes in the rotation and posterior translation patterns were seen after isolated PCL injury, suggesting the kinematics of PCL-deficient knees might be different to normal knees. These factors may contribute to long-term osteoarthritic change. Consequently, when choosing conservative treatment for PCL injury, these changes should be considered to prevent osteoarthritic change. LEVEL OF EVIDENCE: III.