The effect of pelvic movements of a gait training system for stroke patients: a single blind, randomized, parallel study

Background Aging societies lead to higher demand for gait rehabilitation as age-related neurological disorders such as stroke and spinal cord injury increase. Since conventional methods for gait rehabilitation are physically and economically burdensome, robotic gait training systems have been studied and commercialized, many of which provided movements confined in the sagittal plane. For better outcomes of gait rehabilitation with more natural gait patterns, however, it is desirable to provide pelvic movements in the transverse plane. In this study, a robotic gait training system capable of pelvic motions in the transverse plane was used to evaluate the effect of the pelvic motions on stroke patients. Method Healbot T, which is a robotic gait training system and capable of providing pelvic movements in the transverse plane as well as flexion/extension of the hip and knee joints and adduction/abduction of the hip joints, is introduced and used to evaluate the effect of the pelvic movement on gait training of stroke patients. Gait trainings in Healbot T with and without pelvic movements are carried out with stroke patients having hemiparesis. Experiment Twenty-four stroke patients with hemiparesis were randomly assigned into two groups and 23 of them successfully completed the experiment except one subject who had dropped out due to personal reasons. Pelvis-on group was provided with pelvic motions whereas no pelvic movement was allowed for pelvis-off group during 10 sessions of gait trainings in Healbot T. Electromyography (EMG) signals and interaction forces as well as the joint angles of the robot were measured. Gait parameters such as stride length, cadence, and walking speed were measured while walking on the ground without assistance of Healbot T after gait training on 1st, 5th, and 10th day. Result Stride length significantly increased in both groups. Furthermore, cadence and walking speed of the pelvis-on group were increased by 10.6% and 11.8%. Although interaction forces of both groups except the thighs showed no differences, EMG signals from gluteus medius of the pelvis-on group increased by 88.6% during stance phase. In addition, EMG signals of biceps femoris, gastrocnemius medial, and gastrocnemius lateral of the pelvis-on group increased whereas EMG signals of the pelvis-off group except gastrocnemius lateral showed no difference after gait trainings. Conclusion Gait training using a robotic gait training system with pelvic movements was conducted to investigate the effects of lateral and rotational pelvic movements in gait training of stroke patients. The pelvic movements affected to increase voluntary muscle activation during the stance phase as well as cadence and walking speed. Clinical trial registration KCT0003762, 2018-1254, Registered 28 October 2018, https://cris.nih.go.kr/cris/search/search_result_st01_kren.jsp?seq=14310&ltype=&rtype=

Proposal of accurate cup placement procedure during total hip arthroplasty based on pelvic tilt discrepancies in the lateral position

By combining the anatomical-pelvic-plane (APP) positioner with a newly improved navigation system during total hip arthroplasty (THA), it is theoretically possible to determine cup orientation based on the APP while tracking pelvic movement. The purpose of this study was to determine the navigation accuracy and whether the error is related to the pelvic position fixed by the positioner. Fifty hips that underwent primary THA between 2018 and 2020 were analysed. The accuracy was 2.34° at radiographic inclination (RI) and − 5.01° at radiographic anteversion (RA), and the error was within 10° at both RI and RA in only 40 of 50 hips (80.0%). The discrepancy in pelvic sagittal tilt was correlated with the cup orientation error and especially strongly correlated with the RA error (r = − 0.751, p < 0.001). When RI and RA were calculated using a correction formula to determine the true cup orientation based on the pelvic tilt discrepancies, the error in both RI and RA was within 10° in all cases (100%). The navigation accuracy is related to the pelvic position fixed by the positioner, and the correction formula for the target angle that considers pelvic tilt discrepancies can lead to accurate cup placement in the future.

Spinopelvic mobility affects accuracy of acetabular anteversion measurements on cross-table lateral radiographs

Aims Cross-table lateral (CTL) radiographs are commonly used to measure acetabular component anteversion after total hip arthroplasty (THA). The CTL measurements may differ by > 10° from CT scan measurements but the reasons for this discrepancy are poorly understood. Anteversion measurements from CTL radiographs and CT scans are compared to identify spinopelvic parameters predictive of inaccuracy. Methods THA patients (n = 47; 27 males, 20 females; mean age 62.9 years (SD 6.95)) with preoperative spinopelvic mobility, radiological analysis, and postoperative CT scans were retrospectively reviewed. Acetabular component anteversion was measured on postoperative CTL radiographs and CT scans using 3D reconstructions of the pelvis. Two cohorts were identified based on a CTL-CT error of ≥ 10° (n = 11) or < 10° (n = 36). Spinopelvic mobility parameters were compared using independent-samples t-tests. Correlation between error and mobility parameters were assessed with Pearson’s coefficient. Results Patients with CTL error > 10° (10° to 14°) had stiffer lumbar spines with less mean lumbar flexion (38.9°(SD 11.6°) vs 47.4° (SD 13.1°); p = 0.030), different sagittal balance measured by pelvic incidence-lumbar lordosis mismatch (5.9° (SD 18.8°) vs -1.7° (SD 9.8°); p = 0.042), more pelvic extension when seated (pelvic tilt -9.7° (SD 14.1°) vs -2.2° (SD 13.2°); p = 0.050), and greater change in pelvic tilt between supine and seated positions (12.6° (SD 12.1°) vs 4.7° (SD 12.5°); p = 0.036). The CTL measurement error showed a positive correlation with increased CTL anteversion ( r = 0.5; p = 0.001), standing lordosis ( r = 0.23; p = 0.050), seated lordosis ( r = 0.4; p = 0.009), and pelvic tilt change between supine and step-up positions ( r = 0.34; p = 0.010). Conclusion Differences in spinopelvic mobility may explain the variability of acetabular anteversion measurements made on CTL radiographs. Patients with stiff spines and increased compensatory pelvic movement have less accurate measurements on CTL radiographs. Flexion of the contralateral hip is required to obtain clear CTL radiographs. In patients with lumbar stiffness, this movement may extend the pelvis and increase anteversion of the acetabulum on CTL views. Reliable analysis of acetabular component anteversion in this patient population may require advanced imaging with a CT scan. Cite this article: Bone Joint J 2021;103-B(7 Supple B):59–65.

Smartphone-Based Pelvic Movement Asymmetry Measures for Clinical Decision Making in Equine Lameness Assessment

Visual evaluation of hindlimb lameness in the horse is challenging. Objective measurements, simultaneous to visual assessment, are used increasingly to aid clinical decision making. The aim of this study was to investigate the association of pelvic movement asymmetry with lameness scores (UK scale 0–10) of one experienced veterinarian. Absolute values of pelvic asymmetry measures, quantifying differences between vertical minima (AbPDMin), maxima (AbPDMax) and upward movement amplitudes (AbPDUp), were recorded during straight-line trot with a smartphone attached to the sacrum (n = 301 horses). Overall, there was a significant difference between lameness grades for all three asymmetry measures (p < 0.001). Five pair-wise differences (out of 10) were significant for AbPDMin (p ≤ 0.02) and seven for AbPDMax (p ≤ 0.03) and AbPDUp (p ≤ 0.02). Receiver operating curves assessed sensitivity and specificity of asymmetry measures against lameness scores. AbPDUp had the highest discriminative power (area under curve (AUC) = 0.801–0.852) followed by AbPDMax (AUC = 0.728–0.813) and AbPDMin (AUC = 0.688–0.785). Cut-off points between non-lame (grade 0) and lame horses (grades 1–4) with a minimum sensitivity of 75% were identified as AbPDUp ≥ 7.5 mm (67.6% specificity), AbPDMax ≥ 4.5 mm (51.9% specificity) and AbPDMin ≥ 2.5 mm (33.3% specificity). In conclusion, pelvic upward movement amplitude difference (AbPDUp) was the asymmetry parameter with the highest discriminative power in this study.

Pilot Study of Wobble Seat on Trunk Muscles Activity and Kinematics

This paper presents the pilot study of wobble seat on trunk muscles activity and kinematics. For this study the wobble board and wobble board on bearing surface were used to compare muscles activity and body segments kinematics on these different platforms. Two pelvic motions were performed: anterior – posterior and side to side. During this study the electromyography (sEMG) of trunk muscles and motion capture analysis were done. Results showed that sitting on wobble board placed on bearing surface leaded to increment of the activity of deep muscles with smaller pelvic movement in anterior – posterior pelvic motion.

The Effect of Pelvic Movements of a Gait Training System for Stroke Patients

Background: Aging societies lead to higher demand for gait rehabilitation as age-related neurological disorders such as stroke increase. Since conventional methods for gait rehabilitation are physically and economically burdensome, robotic gait training systems have been studied and commercialized, many of which provided movements confined in the sagittal plane. For better outcomes of gait rehabilitation with more natural gait patterns, however, it is desirable to provide pelvic movements in the transverse plane. In this study, a robotic gait training system capable of pelvic motions in the transverse plane was used to evaluated the effect of the pelvic motions on stroke patients. Method: Healbot T, which is a robotic gait training system and capable of providing pelvic movements in the transverse plane as well as flexion/extension of the hip and knee joints and adduction/abduction of the hip joints, is introduced and used to evaluate the effect of the pelvic movement on gait training of stroke patients.Experiment: 23 stroke patients with hemiparesis participated in this study and were assigned into two groups. Pelvis-on group was provided with pelvic motions whereas no pelvic movement was allowed for pelvis-off group during 10 sessions of gait trainings in Healbot T. EMG signals and interaction forces as well as the joint angles of the robot were measured. Gait parameters such as stride length, gait period, cadence, and walking speed were measured after gait training. Result: 37.5 % lower interaction forces of pelvis were observed in the pelvis-on group than the pelvis-off group. Furthermore, the interaction forces at the thighs and calves of both groups showed significant decrease. The EMG signals of gluteus medius of the pelvis-on group increased by 77.2 %. Furthermore, statistically significant increases in various muscles were measured in the pelvis-on group during the stance phase. Conclusion: Gait training using a robotic gait training system with pelvic movements was conducted to study the effects of lateral and rotational pelvic movements in gait training of stroke patients. The pelvic movements made gait training less interfered by the exoskeleton while stimulating the voluntary muscle activation during the stance phase. Clinical trial registration: KCT0003762, 2018-1254, Registered 28 October 2018, https://cris.nih.go.kr/cris/search/search_result_st01_kren.jsp?seq=14310

Relationship between pelvic tilt control, horse-rider synchronisation, and rider position in sitting trot

Investigation of dressage riders suggests that the performance outcomes of riding can be enhanced by a rider correctly adapting the motion of their pelvis. The pelvis has been identified as an important component of the physical connection of the horse and the rider. This preliminary study aimed to assess whether riders with better control of their pelvic movement, had increased postural stability and horse-rider synchronicity. Twenty-six amateur riders competing in Novice to Grand Prix level dressage rode 35 mixed breed horses in active dressage training which they were used to riding. Riders were divided into two groups according to their ability to perform posterior pelvic tilt whilst sat on a Swiss ball. High-speed motion-capture was captured from the left and right sides and used to assess rider body position, angular measurements and horse-rider synchronicity whilst riding a pre-defined test at collected trot on an artificial surface. Appropriate statistical analyses were used to compare variables between groups. Differences between groups were compared using one-way ANOVA or independent samples t-tests; the significance level was set at P<0.05. No riders in the study were able to perform anterior or posterior pelvic tilt whilst seated on a ball without demonstrating mild or major compensations; the most common of these were inclusion of the lumbar spine or leaning forwards or backwards. The results suggest that riders who could not perform pelvic tilt without major compensations had a more leaning forward posture, were more asymmetrical between the left and right sides and more phase shifted during the swing and stance phases than riders who could perform pelvic tilt with mild compensations.

The correlation between the pelvic movement symmetry during motion, as well as body mass and the alignment of the knees of schoolchildren

Introduction: Body posture, including the alignment of the knees, as well as being overweight or obese, has a measurable influence on the way one moves. Most of the somatic and motor dysfunctions, which are often a problem for adults, originated in their childhood. Ailments regarding motor functions among adults are often a consequence of a previously overlooked or untreated dysfunction. Children and teenagers are a large group of patients suffering from dysfunctions of such type. The goal of this research was to assess the degree of influence being overweight or obese and having valgus knees has over children’s pelvic movement symmetry during motion. Materials and methods: 192 primary school students, aged 11-13, from Tarnow and its surrounding areas took part in the study. The alignment of their lower limbs was realised through measuring the distances between their medial malleoli, while standing up, with legs joined at knees. The pelvic movement symmetry while walking was tested with the BTS G-Walk device. Results: Boys have been diagnosed with having excessive body weight and valgus knees alignment more often than girls. A crucial correlation between being overweight or obese and having valgus knees was noted. A notable difference in the pelvic movement symmetry during motion between overweight or obese children and those with correct body weight, as well as between children with valgus and correct knees alignment has been determined. Studying the correlation coefficient has shown that BMI is more relevant than knee alignment to the problem in question. Conclusion: Gait re-education should be a part of kinesitherapy both for the children with valgus knees and those with excessive body weight.