http://informahealthcare.com/idt ISSN 1748-3107 print/ISSN 1748-3115 online Disabil Rehabil Assist Technol, Early Online: 1–5 ! 2013 Informa UK Ltd. DOI: 10.3109/17483107.2013.807442
RESEARCH ARTICLE
Mokhtar Arazpour1, Monireh Ahmadi Bani1, Stephen William Hutchins2, Sarah Curran3, Mohammad Ali Javanshir4, and Mohammad Ebrahim Mousavi1 1
Orthotics and Prosthetics Department, University of Social Welfare and Rehabilitation Science, Tehran, Iran, 2IHSCR, Faculty of Health & Social Care, University of Salford, Salford, UK, 3Cardiff School of Health Sciences, Llandaff Campus, Cardiff Metropolitan University, Wales CF5 2YB, UK, and 4Department of Orthotics and Prosthetics, Iran University of Medical Science, Rehabilitation Faculty, Tehran, Iran
Abstract
Keywords
Objectives: Gait training has been shown to improve the walking performance of spinal cordinjured (SCI) patients. The use of powered hip orthoses (PHO) during gait training is one approach which could potentially improve rehabilitative outcomes for such subjects. The aim of this study was therefore to evaluate the influence of a PHO on the kinematics and temporal– spatial parameters of walking by SCI patients. Methods: Four SCI patients participated in this study. Gait evaluation was performed at baseline and at 10 weeks following intervention with the use of a PHO and gait re-training. Walking speed, step length, vertical and horizontal compensatory motions and hip joint kinematics were analysed prior to and following the training regime. Results: Significant increases in walking speed and step length were demonstrated by the SCI patients when walking with the PHO following orthotic gait training. Sagittal plane hip range of motion also increased, but not significantly. However, vertical and horizontal compensatory motions decreased significantly. Conclusions: Positive effects on the kinematics and temporal–spatial parameters of gait by SCI subjects were demonstrated following a period of gait training with a PHO. Further studies are therefore warranted to confirm their long term effects on the rehabilitation of SCI subjects.
Gait training, powered hip orthosis, spinal cord injury, walking History Received 29 January 2013 Revised 15 May 2013 Accepted 18 May 2013 Published online 19 June 2013
ä Implications for Rehabilitation
Powered hip orthosis could be used by spinal cord injury patients. A major advantage of the orthotic gait training with powered hip orthosis was regeneration of hip movement closer to that of normal human walking. The orthotic gait training with the powered hip orthosis improved the kinematics and temporalspatial parameters in a spinal cord injury patient which also produced near-normal hip joint angle patterns during gait.
Introduction Spinal cord injury (SCI) patients are confined to a wheelchair for the most part of their activity of daily living (ADL). Complications such as spasticity, joint contractures, pressure sores, osteoporosis and urinary tract infections may be present in a significant number of paraplegic subjects [1,2]. The ability to stand and walk produces physiological and psychological benefits for subjects affected by SCI [3]. A reduction of bed sores, osteoporosis, spasticity, contractures and improvement of bladder and bowel functions, have all been reported when patients with SCI stand and walk [1,4]. Gait training with powered gait orthoses (PGOs) is a new and emerging intervention which can help in the Address for correspondence: Mohammad Ali Javanshir, Department of Orthotics and Prosthetics, Iran University of Medical Science, Rehabilitation Faculty, Mirdamad Blvd, Shahnazari Street, Tehran, Iran. Tel: +98 (21) 22 18 00 10. Fax: +98 (21) 22 18 00 49. E-mail: M.ali_javanshir @yahoo.com
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Influence of orthotic gait training with powered hip orthosis on walking in paraplegic patients
rehabilitation of SCI subjects by providing walking and standing activities [5]. PGOs can facilitate ambulation in both the clinical situation and in the home for paraplegic patients [6]. The development, design and construction of powered orthoses started in the mid1970s [7]. Miomir Vukobratovic by using pneumatic actuators at the hip, knee and ankle joints developed one of the first powered orthoses, but walking speed was reported as being low when paraplegic patients walked with it donned [7]. Ali Seireg, by using hydraulic actuators at the hip, knee and ankle joints, fabricated a PGO which provided walking and stepping actions for a single SCI patient [8]. Belforte et al. [9,10] and Kang et al. [11] also developed PGOs which used pneumatic actuators which had positive effects on the walking of SCI patients. Rotenberg et al. [12], Ohta et al. [6] and Arazpour et al. [13] by using electric actuators confirmed the positive effect of this type of orthosis on walking by paraplegic patients.
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Studies have also considered the possibility of supplementing the gait orthosis with additional technology such as active knee or hip mechanisms to improve patients’ performance. Ohta et al. [6] reported improvements in walking speed and reduction of lateral and vertical compensatory motion when analysing the effect of using an advanced reciprocating gait orthosis (ARGO) with a motorized hip joint actuator. However, due to its bulky structure, this system could not be used for ADLs. Audu et al. [14] designed and constructed a reciprocal gait orthosis (RGO) with a variable constraint hip mechanism (VCHM). Gait evaluation using healthy subjects demonstrated a 25% reduction in speed of walking with the VCHM powered orthosis when compared to normal walking. Moreover, the relative magnitudes of the electromyography (EMG) of tibialis anterior, quadriceps and hamstrings were also higher with the VCHM compared to the isocentric reciprocating gait orthosis (IRGO) or normal walking. This was thought to be due to the additional weight of the new powered gait orthosis. Kang et al. [11] developed a powered IRGO using pneumatic actuators and evaluated it when worn by three paraplegic patients. The results demonstrated improvements in walking speed, pelvic tilt, flexion and extension angles of the hip and stance and swing phase times when compared to an un-adapted mechanical IRGO. Akahira et al. [15] compared a standard ARGO with one ARGO utilizing powered knee joints on six SCI patients and demonstrated that the powered ARGO had the potential to activate muscle activity in the paralysed lower limb as compared to the standard ARGO. Nakasawa et al. [16] reported an induction of muscle activity in the lower limbs which occurred following 1 h of gait training with the weight bearing control orthosis (WBCO) 5 days/week for 12 weeks in three SCI patients. In addition, Kojima et al. [17] demonstrated the positive effect of a WBCO in a SCI patient by providing lower limb loading and muscle activity. Arazpour et al. [18] when evaluating of the effect of a PGO on four SCI individuals in both separate and synchronized movements with actuated orthotic hip and knee joints compared to walking with an IRGO demonstrated that using separate and synchronized actuated movement of the hip and knee joints in the PGO increased gait speed and step length and reduced lateral and vertical compensatory motions when compared to an IRGO. Arazpour et al. [13] also evaluated a powered hip orthosis (PHO) when worn by a single SCI subject with a lesion level of T8. Gait evaluation was performed when walking with an IRGO and compared to that demonstrated by a newly powered version of the orthosis; based on the IRGO superstructure but incorporating powered hip joints using an electrically motorized actuator that produced active hip joint extension and flexion. Walking with new PHO increased walking speed, step length, cadence and sagittal plane hip motion whilst also decreasing vertical and horizontal compensatory motions. This hip orthosis seemed particularly promising but had been only minimally tested. Therefore the aim of this study was to replicate the pilot work of Arazpour et al. [13] and further evaluate the effects of the orthosis on the kinematics and temporal spatial parameters (speed of walking, cadence and step length) when orthotic gait training was performed on a cohort of SCI patients.
Materials and methods Subjects and orthotic gait training Four SCI patients (mean age 26.5 3.31 years with levels of injury ranging from T6 to T12 and a mean time post injury of 26.75 18.87 months) volunteered to participate in this study. Table 1 shows the characteristics of the participants. The inclusion criteria used to select subjects for this study included subjects with SCI with a thoracic level involvement with at least 6-month post-injury duration to stabilize neurological and emotional conditions, and the ability to perform passive a full ranges of motion in the hips, knees and ankle joints, plus the existence of adequate power in their upper extremity in order to be able to use a walking frame or elbow crutches for walking with the orthosis, and no history of cardiovascular or pulmonary disease, contractures or severe spasticity or obesity. Clinical evaluation of patients was performed using the American Spinal Injury Association (ASIA) impairment scale [19]. All of patients had grade A (Complete: No motor or sensory function is preserved in the sacral segments S4–S5) or B ASIA (incomplete: Sensory but not motor function is preserved below the neurological level and
Figure 1. The powered hip mechanism used in this study. Table 1. Characteristics of the SCI participants. Patient
Gender
Age (years)
Height (cm)
Weight (kg)
1 2 3 4
Male Female Male Female
29.0 22.0 26.0 29.0
165.0 165.0 178.0 160.0
53.0 54.0 65.0 59.0
Level of injury T12 T8 T10 T6
ASIA score
Time since injury (months)
B B A B
32.0 51.0 15.0 9.0
Orthotic gait training with PHO
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DOI: 10.3109/17483107.2013.807442
includes the sacral segments S4–S5). The PHO used for the gait training of the volunteer SCI patients is shown in Figure 1. The orthosis was custom made and fitted according to patient’s lower limb length, and the ankle foot orthosis portions of the orthosis were made after casting the lower extremities. A period of trunk, upper limb and lower limb stretching was initially performed to ensure adequate balance in standing and walking with the orthosis and for contracture management. In addition, training was given on the control and use of the walker, in an orthotics rehabilitation centre. The patients undertook orthotic gait training with the new PHO for a minimum of 6 weeks (subjects T12 and T10) and maximum of 10 weeks (subjects T8 and T6), at 1 h/day for 5 days per week prior to the walking trials. After the prescribed training regime had been completed, each patient could walk with the new PHO independently, and were able to walk continuously. The structure of orthosis and its efficacy when worn by one SCI patient has been described in a previously publication [13]. The mechanical IRGO was powered by a single electrical motor which actuated the right orthotic hip joint. Activation of this joint in flexion caused extension of left side hip joint due to the mechanical linkage within the orthosis. The PHO increased walking speed, step length and also the cadence when compared to an un-adapted IRGO worn by the SCI patient. In addition vertical and horizontal compensatory motions decreased with new orthosis and the pattern of hip joint angles was comparative to normal walking patterns when walking with this orthosis [13]. Walking analysis was performed in the Biomechanics Laboratory of the Ergonomy Department of University of Social Welfare and Rehabilitation Sciences. The SCI patients who volunteered for the study and were permitted to exclude themselves at any time. Before participation in the study, the patients read and approved a statement acknowledging informed consent. The Ethics Committee of the University of Social Welfare and Rehabilitation Sciences approved the performance of this study.
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evaluations were performed with a three-dimensional motionanalysis system (VICON460, Oxford Metrics, UK). The motionanalysis system used a conventional video-analysis system with six cameras and two Kistler force plates (Kistler, Switzerland). These force plates enabled stance phase and gait parameter data to be acquired. Fifteen markers were placed bilaterally on the lower extremity in positions of the greater trochanter, lateral condyle of the femur, head and lateral malleolus of the fibula, the second metatarsal, ASIS, calcaneus and four markers were used over the jugular notch, spinous process of the seventh cervical vertebrae and the acromio clavicular joints on the trunk. Markers used to replicate the lower extremity were placed on the uprights of orthosis as close as possible to the considered points. These measurements were taken twice – at baseline and after 10 weeks of orthosis use. Gait evaluation was performed when patients walked along a 10-m walkway five times at their self-selected speed. Two step cycles were selected for gait analysis (i.e. one right and one left to replicate a complete stride), and were averaged from the five walking trials for each condition. There were no significant differences between left and right. During walking the patients used a walking frame. Primary outcome measures were walking speed, cadence, step length, compensatory motions and kinematics of hip joint which were assessed prior to and following completion of the 10 week of use by each SCI patient. Statistical analysis According to the small sample size (n ¼ 10), a normal distribution could not be assumed. The Wilcoxon signed ranks test as a nonparametric was used to evaluate differences in parameters for all four subjects (JMP IN software, SAS Institute, Inc., Cary, NC). SPSS 16 was used for data analysis. The significant level considered was a 0.05.
Results
Experiments
Gait speed, step length and cadence
To enable analysis of the kinematic and temporal spatial parameters after gait training with the new PHO, walking
Tables 2 and 3 show the mean SD and range of walking speed, cadence and step length at baseline and after 10 weeks of gait
Table 2. Mean SD of gait parameters when comparing baseline and after the orthotic gait training with PHO conditions. Walking with PHO before orthotic gait training
Walking with PHO after orthotic gait training
p Value
36.8 3.76 51.89 11 0.32 0.09 21.27 11.76 8.42 2.7 10 5.22 6.25 0.95
40.6 3.94 53.8 11 0.36 0.09 19.32 11.61 7.32 2.26 18.25 2.06 7.5 0.57
0.068 0.144 0.063 0.068 0.068 0.068 0.102
Step length (cm) Cadence (steps/min) Speed of walking (m/s) Lateral compensatory motion (cm) Vertical compensatory motion (cm) Hip flexion (degree) Hip extension (degree)
Table 3. Range of gait parameters when comparing baseline values and those demonstrated after the orthotic gait training with the PHO for four SCI subjects. Subject 1
Step length (cm) Cadence (steps/min) Speed of walking (m/s) Lateral compensatory motion (cm) Vertical compensatory motion (cm) Hip flexion (degree) Hip extension (degree)
Subject 2
Subject 3
Subject 4
Before
After
Before
After
Before
After
Before
After
36.80 40.76 0.25 35.70 11.50 14.00 6.00
39.70 43.82 0.29 33.70 10.10 16.00 8.00
36.40 44.50 0.27 23.70 9.80 15.00 7.00
41.90 44.39 0.31 21.40 8.20 18.00 8.00
41.60 64.90 0.45 7.40 5.60 6.00 5.00
45.10 66.51 0.50 5.70 5.10 21.00 7.00
32.40 57.40 0.31 18.30 6.80 5.00 7.00
35.70 60.50 0.36 16.50 5.90 18.00 7.00
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Figure 2. Hip flexion/extension during baseline and after gait training with the PHO.
training with PHO. There were no significant differences noted between the selected gait parameters before and after orthotic gait training. However, self-selected walking speed, step length and cadence were all increased by 12%, 10% and 3%, respectively, in SCI patients after orthotic gait training compared to baseline. This coincided with increased hip flexion (82%) and extension (20%) after orthotic gait training compared to baseline. Comparison of injury level regarding gait parameters Table 3 demonstrates the alteration to walking parameters for the SCI subjects before and after orthotic gait training. The results demonstrated that patients with a higher level of SCI had lower walking speeds and shorter step lengths as compared to patients with a lower levels of SCI. Those subjects with lower mean values of gait parameters in this study experienced a more limited hip range of motion when using the orthosis and had a higher thoracic level of injury. These results corresponded with those demonstrated in previous studies [20,21]. Lateral and vertical compensatory motions The mean SD and range of these parameters before and after orthotic gait training are demonstrated in Tables 2 and 3. Gait training with the PHO improved lateral and vertical compensatory motions compared to baseline, but there was no significant difference between baseline and following orthotic gait training in these parameters (Table 2). Kinematics Hip angle Mean SD (range) of hip flexion/extension during baseline and after gait training with the PHO are demonstrated in Tables 2 and 3 and Figure 2. The maximum hip flexion and extension angles were 18.25 2.06 and 7.5 0.57 after gait training, but average flexion and extension angles were 10 5.22 and 6.25 0.95 in baseline when walking with PGO pre-gait training. There were no significant differences in flexion and extension parameters between walking with PGO pre and post gait training (p50.05) (Table 2).
Discussion The effect of gait training with the PHO on the kinematics and temporal spatial parameters in four SCI subjects was evaluated in
this study. The new powered orthosis PHO was able to provide dynamic hip joint movements during stance and swing phase of the gait cycle, without any falling and or balance problems being experienced by the volunteer subjects during the walking trials. However, it was found that hip joint kinematics and temporal spatial parameters (walking speed and step length) were not significantly improved by induction of activated hip joint motion. The low sample size (n ¼ 4) may have produced this result. During walking with the PHO orthosis, SCI patients used their trunk muscles to ambulate with the un-adapted mechanical orthosis. In this way, flexion of the trunk can cause excessive vertical and lateral compensatory motions. Gait training for at least 6 to 10 weeks with the powered gait orthosis reduced these compensatory motions compared to baseline. Reduction of compensatory motion can cause a reduction of energy consumption. High energy consumption and fatigue have been reported as one of the main reasons of rejection of mechanical orthosis use by SCI subjects [22]. Based on the reduction of compensatory motions demonstrated after gait training with the PHO, we can deduce that this PHO may reduce energy consumption when being used by SCI patients when compared to non-powered versions. However, this parameter was not evaluated in this study, and further studies regarding analysis of energy consumption will enable confirmation of this effect in this field of orthotic intervention. Activated motion in the orthotic hip joint in conjunction with walking training with the orthosis increased step length and walking speed in all of the subjects tested, and their pattern of sagittal plane hip motion more closely matched that of normal walking. The hip joint range of motions when walking with the PHO was still less than the mean of this parameters in normal human gait, but the overall pattern of hip joint movement was similar to a normal human pattern (Figure 2). However, the maximum extension angle of hip joint occurred much earlier compared to normal gait both during walking with PHO at baseline (30% of the gait cycle), and after orthotic gait training (45% of the gait cycle). The gait training with the orthosis demonstrated the positive effect of producing a hip flexion and extension pattern similar to that of normal walking. The reduction of mean of hip joint range of motion compared to normal value of this parameter may been due to the fact that both knees were fixed in extension and both ankles were placed in a neutral position within the orthosis. The available range of motion for lower limb joints when using the PHO were hip flexion (18.25 ), hip extension (7.5 ), knee flexion and extension (0 ), plantar flexion and dorsi flexion of ankle joint
DOI: 10.3109/17483107.2013.807442
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(0 ). Gait training demonstrated only timing improvements in hip joint kinematics and no effect on the mean flexion and extension of the hip joints. In comparison with previous studies in this field, the findings of this study demonstrated faster walking speeds and improvements in step length by SCI subjects compared to studies by Ohta et al. [6] when using powered hip and knee joints actuated separately, Kawashima et al. [23] when evaluating a WBCO with an activated foot plate, Leung et al. [24] in analysis of walking with an IRGO, plus studies by Mussucci et al. [25] and Ljzerman et al. [26]. These parameters were improved following the completion of the 10 weeks of gait training in this study. This study also investigated whether activated hip movement would improve kinematic and temporal spatial parameters in paraplegic patients. This is because activated hip movement would cause the afferent inputs to be sent from the muscles around the hip joint in the SCI patients. The present results therefore propose that the hip activated movement have a potential to support the neuromuscular performance in the paralysed lower limb. Activation of paralysed lower limb muscles has been reported in SCI patients when using rehabilitation via body weight supported rehabilitation [27–29] and walking with powered gait orthosis [16,17]. Harkema et al. [29] and Dietz et al. [30] reported inputs from lower limb loading and hip joint motion are critical role in generation of muscle activity in SCI patients. In this study the muscle activity of paralysed muscles was not evaluated and further studies in this field in evaluation of the effect of the PHO on this parameter will be beneficial in rehabilitation of SCI patients.
Conclusion This study evaluated the influence of gait training with a PHO on kinematics and temporal spatial parameters in paraplegic patients. This study demonstrated the new PGO improved hip joint motion patterns, increased walking speed and step length and decreased lateral and vertical compensatory motions during level-ground walking trials. This device may therefore be considered as an alternative device for providing gait training for paraplegic subjects.
Declaration of interest The authors do not have any conflicts of interest with regards to the study presented in this paper.
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8. Seireg A, Grundmann J. Design of a multitask exoskeletal walking device. In: Ghista D, ed. Biomechanics of medical devices. New York: Marcel Dekker; 1981:569–639. 9. Belforte G, Gastaldi L, Sorli M. Pneumatic active gait orthosis. Mechatronics 2001;11:301–23. 10. Belforte G, Eula G, Appendino S, Sirolli S. Pneumatic interactive gait rehabilitation orthosis: design and preliminary testing. Proc IME H J Eng Med 2011;225:158–69. 11. Kang S, Ryu J, Moon I, et al. Walker gait analysis of powered gait orthosis for paraplegic. World Congress on Medical Physics and Biomedical Engineering 2006 Springer; 2007. 12. Ruthenberg B, Wasylewski N, Beard J. An experimental device for investigating the force and power requirements of a powered gait orthosis. Development 1997;34:203–13. 13. Arazpour M, Chitsazan A, Hutchins SW, et al. Evaluation of a novel powered hip orthosis for walking by a spinal cord injury patient: a single case study. Prosthet Orthot Int 2012;36:105–12. 14. Audu ML, To CS, Kobetic R, Triolo RJ. Gait evaluation of a novel hip constraint orthosis with implication for walking in paraplegia. IEEE Trans Neural Syst Rehabil Eng 2010;18:610–18. 15. Akahira H, Yamaguchi Y, Nakazawa K, et al. Effect of dynamic knee motion on paralyzed lower limb muscle activity during orthotic gait: a test for the effectiveness of the motor-assisted knee motion device. J Nov Physiother 2012;1:2. 16. Nakazawa K, Kakihana W, Kawashima N, et al. Induction of locomotor-like EMG activity in paraplegic persons by orthotic gait training. Exp Brain Res 2004;157:117–23. 17. Kojima N, Nakazawa K, Yano H. Effects of limb loading on the lower-limb electromyographic activity during orthotic locomotion in a paraplegic patient. Neurosci Lett 1999;274:211. 18. Arazpour M, Bani MA, Kashani RV, et al. Effect of powered gait orthosis on walking in individuals with paraplegia. Prosthet Orthot Int 2012;PMID:23172910. 19. Maynard FM Jr, Bracken MB, Creasey G, et al. International standards for neurological and functional classification of spinal cord injury. Am Spinal Inj Assoc Spinal Cord 1997;35:266. 20. Bani MA, Arazpour M, Ghomshe FT, et al. Gait evaluation of the advanced reciprocating gait orthosis with solid versus dorsi flexion assist ankle foot orthoses in paraplegic patients. Prosthet Orthot Int 2013;37:161–7. 21. Kawashima N, Taguchi D, Nakazawa K, Akai M. Effect of lesion level on the orthotic gait performance in individuals with complete paraplegia. Spinal Cord 2006;44:487–94. 22. Arazpour M, Chitsazan A, Hutchins SW, et al. Design and simulation of a new powered gait orthosis for paraplegic patients. Prosthet Orthot Int 2012;36:125–30. 23. Kawashima N, Sone Y, Nakazawa K, et al. Energy expenditure during walking with weight-bearing control (WBC) orthosis in thoracic level of paraplegic patients. Spinal Cord 2003;41:506–10. 24. Leung A, Wong A, Wong E, Hutchins S. The physiological cost index of walking with an isocentric reciprocating gait orthosis among patients with T 12–L 1 spinal cord injury. Prosthet Orthot Int 2009;33:61–8. 25. Massucci M, Brunetti G, Piperno R, et al. Walking with the advanced reciprocating gait orthosis (ARGO) in thoracic paraplegic patients: energy expenditure and cardiorespiratory performance. Spinal Cord 1998;36:223–7. 26. Ijzerman MJ, Baardman G, van’t Hof MA, et al. Validity and reproducibility of crutch force and heart rate measurements to assess energy expenditure of paraplegic gait. Archiv Phys Med Rehabil 1999;80:1017–23. 27. Dietz V, Colombo G, Jensen L, Baumgartner L. Locomotor capacity of spinal cord in paraplegic patients. Ann Neurol 1995; 37:574–82. 28. Dobkin B, Harkema S, Requejo P, Edgerton V. Modulation of locomotor-like EMG activity in subjects with complete and incomplete spinal cord injury. J Neurol Rehabil 1995;9:183–90. 29. Harkema SJ, Hurley SL, Patel UK, et al. Human lumbosacral spinal cord interprets loading during stepping. J Neurophysiol 1997;77: 797–811. 30. Dietz V, Mu¨ller R, Colombo G. Locomotor activity in spinal man: significance of afferent input from joint and load receptors. Brain 2002;125:2626–34.
RESEARCH ARTICLE
Mokhtar Arazpour1, Monireh Ahmadi Bani1, Stephen William Hutchins2, Sarah Curran3, Mohammad Ali Javanshir4, and Mohammad Ebrahim Mousavi1 1
Orthotics and Prosthetics Department, University of Social Welfare and Rehabilitation Science, Tehran, Iran, 2IHSCR, Faculty of Health & Social Care, University of Salford, Salford, UK, 3Cardiff School of Health Sciences, Llandaff Campus, Cardiff Metropolitan University, Wales CF5 2YB, UK, and 4Department of Orthotics and Prosthetics, Iran University of Medical Science, Rehabilitation Faculty, Tehran, Iran
Abstract
Keywords
Objectives: Gait training has been shown to improve the walking performance of spinal cordinjured (SCI) patients. The use of powered hip orthoses (PHO) during gait training is one approach which could potentially improve rehabilitative outcomes for such subjects. The aim of this study was therefore to evaluate the influence of a PHO on the kinematics and temporal– spatial parameters of walking by SCI patients. Methods: Four SCI patients participated in this study. Gait evaluation was performed at baseline and at 10 weeks following intervention with the use of a PHO and gait re-training. Walking speed, step length, vertical and horizontal compensatory motions and hip joint kinematics were analysed prior to and following the training regime. Results: Significant increases in walking speed and step length were demonstrated by the SCI patients when walking with the PHO following orthotic gait training. Sagittal plane hip range of motion also increased, but not significantly. However, vertical and horizontal compensatory motions decreased significantly. Conclusions: Positive effects on the kinematics and temporal–spatial parameters of gait by SCI subjects were demonstrated following a period of gait training with a PHO. Further studies are therefore warranted to confirm their long term effects on the rehabilitation of SCI subjects.
Gait training, powered hip orthosis, spinal cord injury, walking History Received 29 January 2013 Revised 15 May 2013 Accepted 18 May 2013 Published online 19 June 2013
ä Implications for Rehabilitation
Powered hip orthosis could be used by spinal cord injury patients. A major advantage of the orthotic gait training with powered hip orthosis was regeneration of hip movement closer to that of normal human walking. The orthotic gait training with the powered hip orthosis improved the kinematics and temporalspatial parameters in a spinal cord injury patient which also produced near-normal hip joint angle patterns during gait.
Introduction Spinal cord injury (SCI) patients are confined to a wheelchair for the most part of their activity of daily living (ADL). Complications such as spasticity, joint contractures, pressure sores, osteoporosis and urinary tract infections may be present in a significant number of paraplegic subjects [1,2]. The ability to stand and walk produces physiological and psychological benefits for subjects affected by SCI [3]. A reduction of bed sores, osteoporosis, spasticity, contractures and improvement of bladder and bowel functions, have all been reported when patients with SCI stand and walk [1,4]. Gait training with powered gait orthoses (PGOs) is a new and emerging intervention which can help in the Address for correspondence: Mohammad Ali Javanshir, Department of Orthotics and Prosthetics, Iran University of Medical Science, Rehabilitation Faculty, Mirdamad Blvd, Shahnazari Street, Tehran, Iran. Tel: +98 (21) 22 18 00 10. Fax: +98 (21) 22 18 00 49. E-mail: M.ali_javanshir @yahoo.com
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Influence of orthotic gait training with powered hip orthosis on walking in paraplegic patients
rehabilitation of SCI subjects by providing walking and standing activities [5]. PGOs can facilitate ambulation in both the clinical situation and in the home for paraplegic patients [6]. The development, design and construction of powered orthoses started in the mid1970s [7]. Miomir Vukobratovic by using pneumatic actuators at the hip, knee and ankle joints developed one of the first powered orthoses, but walking speed was reported as being low when paraplegic patients walked with it donned [7]. Ali Seireg, by using hydraulic actuators at the hip, knee and ankle joints, fabricated a PGO which provided walking and stepping actions for a single SCI patient [8]. Belforte et al. [9,10] and Kang et al. [11] also developed PGOs which used pneumatic actuators which had positive effects on the walking of SCI patients. Rotenberg et al. [12], Ohta et al. [6] and Arazpour et al. [13] by using electric actuators confirmed the positive effect of this type of orthosis on walking by paraplegic patients.
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Studies have also considered the possibility of supplementing the gait orthosis with additional technology such as active knee or hip mechanisms to improve patients’ performance. Ohta et al. [6] reported improvements in walking speed and reduction of lateral and vertical compensatory motion when analysing the effect of using an advanced reciprocating gait orthosis (ARGO) with a motorized hip joint actuator. However, due to its bulky structure, this system could not be used for ADLs. Audu et al. [14] designed and constructed a reciprocal gait orthosis (RGO) with a variable constraint hip mechanism (VCHM). Gait evaluation using healthy subjects demonstrated a 25% reduction in speed of walking with the VCHM powered orthosis when compared to normal walking. Moreover, the relative magnitudes of the electromyography (EMG) of tibialis anterior, quadriceps and hamstrings were also higher with the VCHM compared to the isocentric reciprocating gait orthosis (IRGO) or normal walking. This was thought to be due to the additional weight of the new powered gait orthosis. Kang et al. [11] developed a powered IRGO using pneumatic actuators and evaluated it when worn by three paraplegic patients. The results demonstrated improvements in walking speed, pelvic tilt, flexion and extension angles of the hip and stance and swing phase times when compared to an un-adapted mechanical IRGO. Akahira et al. [15] compared a standard ARGO with one ARGO utilizing powered knee joints on six SCI patients and demonstrated that the powered ARGO had the potential to activate muscle activity in the paralysed lower limb as compared to the standard ARGO. Nakasawa et al. [16] reported an induction of muscle activity in the lower limbs which occurred following 1 h of gait training with the weight bearing control orthosis (WBCO) 5 days/week for 12 weeks in three SCI patients. In addition, Kojima et al. [17] demonstrated the positive effect of a WBCO in a SCI patient by providing lower limb loading and muscle activity. Arazpour et al. [18] when evaluating of the effect of a PGO on four SCI individuals in both separate and synchronized movements with actuated orthotic hip and knee joints compared to walking with an IRGO demonstrated that using separate and synchronized actuated movement of the hip and knee joints in the PGO increased gait speed and step length and reduced lateral and vertical compensatory motions when compared to an IRGO. Arazpour et al. [13] also evaluated a powered hip orthosis (PHO) when worn by a single SCI subject with a lesion level of T8. Gait evaluation was performed when walking with an IRGO and compared to that demonstrated by a newly powered version of the orthosis; based on the IRGO superstructure but incorporating powered hip joints using an electrically motorized actuator that produced active hip joint extension and flexion. Walking with new PHO increased walking speed, step length, cadence and sagittal plane hip motion whilst also decreasing vertical and horizontal compensatory motions. This hip orthosis seemed particularly promising but had been only minimally tested. Therefore the aim of this study was to replicate the pilot work of Arazpour et al. [13] and further evaluate the effects of the orthosis on the kinematics and temporal spatial parameters (speed of walking, cadence and step length) when orthotic gait training was performed on a cohort of SCI patients.
Materials and methods Subjects and orthotic gait training Four SCI patients (mean age 26.5 3.31 years with levels of injury ranging from T6 to T12 and a mean time post injury of 26.75 18.87 months) volunteered to participate in this study. Table 1 shows the characteristics of the participants. The inclusion criteria used to select subjects for this study included subjects with SCI with a thoracic level involvement with at least 6-month post-injury duration to stabilize neurological and emotional conditions, and the ability to perform passive a full ranges of motion in the hips, knees and ankle joints, plus the existence of adequate power in their upper extremity in order to be able to use a walking frame or elbow crutches for walking with the orthosis, and no history of cardiovascular or pulmonary disease, contractures or severe spasticity or obesity. Clinical evaluation of patients was performed using the American Spinal Injury Association (ASIA) impairment scale [19]. All of patients had grade A (Complete: No motor or sensory function is preserved in the sacral segments S4–S5) or B ASIA (incomplete: Sensory but not motor function is preserved below the neurological level and
Figure 1. The powered hip mechanism used in this study. Table 1. Characteristics of the SCI participants. Patient
Gender
Age (years)
Height (cm)
Weight (kg)
1 2 3 4
Male Female Male Female
29.0 22.0 26.0 29.0
165.0 165.0 178.0 160.0
53.0 54.0 65.0 59.0
Level of injury T12 T8 T10 T6
ASIA score
Time since injury (months)
B B A B
32.0 51.0 15.0 9.0
Orthotic gait training with PHO
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DOI: 10.3109/17483107.2013.807442
includes the sacral segments S4–S5). The PHO used for the gait training of the volunteer SCI patients is shown in Figure 1. The orthosis was custom made and fitted according to patient’s lower limb length, and the ankle foot orthosis portions of the orthosis were made after casting the lower extremities. A period of trunk, upper limb and lower limb stretching was initially performed to ensure adequate balance in standing and walking with the orthosis and for contracture management. In addition, training was given on the control and use of the walker, in an orthotics rehabilitation centre. The patients undertook orthotic gait training with the new PHO for a minimum of 6 weeks (subjects T12 and T10) and maximum of 10 weeks (subjects T8 and T6), at 1 h/day for 5 days per week prior to the walking trials. After the prescribed training regime had been completed, each patient could walk with the new PHO independently, and were able to walk continuously. The structure of orthosis and its efficacy when worn by one SCI patient has been described in a previously publication [13]. The mechanical IRGO was powered by a single electrical motor which actuated the right orthotic hip joint. Activation of this joint in flexion caused extension of left side hip joint due to the mechanical linkage within the orthosis. The PHO increased walking speed, step length and also the cadence when compared to an un-adapted IRGO worn by the SCI patient. In addition vertical and horizontal compensatory motions decreased with new orthosis and the pattern of hip joint angles was comparative to normal walking patterns when walking with this orthosis [13]. Walking analysis was performed in the Biomechanics Laboratory of the Ergonomy Department of University of Social Welfare and Rehabilitation Sciences. The SCI patients who volunteered for the study and were permitted to exclude themselves at any time. Before participation in the study, the patients read and approved a statement acknowledging informed consent. The Ethics Committee of the University of Social Welfare and Rehabilitation Sciences approved the performance of this study.
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evaluations were performed with a three-dimensional motionanalysis system (VICON460, Oxford Metrics, UK). The motionanalysis system used a conventional video-analysis system with six cameras and two Kistler force plates (Kistler, Switzerland). These force plates enabled stance phase and gait parameter data to be acquired. Fifteen markers were placed bilaterally on the lower extremity in positions of the greater trochanter, lateral condyle of the femur, head and lateral malleolus of the fibula, the second metatarsal, ASIS, calcaneus and four markers were used over the jugular notch, spinous process of the seventh cervical vertebrae and the acromio clavicular joints on the trunk. Markers used to replicate the lower extremity were placed on the uprights of orthosis as close as possible to the considered points. These measurements were taken twice – at baseline and after 10 weeks of orthosis use. Gait evaluation was performed when patients walked along a 10-m walkway five times at their self-selected speed. Two step cycles were selected for gait analysis (i.e. one right and one left to replicate a complete stride), and were averaged from the five walking trials for each condition. There were no significant differences between left and right. During walking the patients used a walking frame. Primary outcome measures were walking speed, cadence, step length, compensatory motions and kinematics of hip joint which were assessed prior to and following completion of the 10 week of use by each SCI patient. Statistical analysis According to the small sample size (n ¼ 10), a normal distribution could not be assumed. The Wilcoxon signed ranks test as a nonparametric was used to evaluate differences in parameters for all four subjects (JMP IN software, SAS Institute, Inc., Cary, NC). SPSS 16 was used for data analysis. The significant level considered was a 0.05.
Results
Experiments
Gait speed, step length and cadence
To enable analysis of the kinematic and temporal spatial parameters after gait training with the new PHO, walking
Tables 2 and 3 show the mean SD and range of walking speed, cadence and step length at baseline and after 10 weeks of gait
Table 2. Mean SD of gait parameters when comparing baseline and after the orthotic gait training with PHO conditions. Walking with PHO before orthotic gait training
Walking with PHO after orthotic gait training
p Value
36.8 3.76 51.89 11 0.32 0.09 21.27 11.76 8.42 2.7 10 5.22 6.25 0.95
40.6 3.94 53.8 11 0.36 0.09 19.32 11.61 7.32 2.26 18.25 2.06 7.5 0.57
0.068 0.144 0.063 0.068 0.068 0.068 0.102
Step length (cm) Cadence (steps/min) Speed of walking (m/s) Lateral compensatory motion (cm) Vertical compensatory motion (cm) Hip flexion (degree) Hip extension (degree)
Table 3. Range of gait parameters when comparing baseline values and those demonstrated after the orthotic gait training with the PHO for four SCI subjects. Subject 1
Step length (cm) Cadence (steps/min) Speed of walking (m/s) Lateral compensatory motion (cm) Vertical compensatory motion (cm) Hip flexion (degree) Hip extension (degree)
Subject 2
Subject 3
Subject 4
Before
After
Before
After
Before
After
Before
After
36.80 40.76 0.25 35.70 11.50 14.00 6.00
39.70 43.82 0.29 33.70 10.10 16.00 8.00
36.40 44.50 0.27 23.70 9.80 15.00 7.00
41.90 44.39 0.31 21.40 8.20 18.00 8.00
41.60 64.90 0.45 7.40 5.60 6.00 5.00
45.10 66.51 0.50 5.70 5.10 21.00 7.00
32.40 57.40 0.31 18.30 6.80 5.00 7.00
35.70 60.50 0.36 16.50 5.90 18.00 7.00
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M. Arazpour et al.
Disabil Rehabil Assist Technol, Early Online: 1–5
Figure 2. Hip flexion/extension during baseline and after gait training with the PHO.
training with PHO. There were no significant differences noted between the selected gait parameters before and after orthotic gait training. However, self-selected walking speed, step length and cadence were all increased by 12%, 10% and 3%, respectively, in SCI patients after orthotic gait training compared to baseline. This coincided with increased hip flexion (82%) and extension (20%) after orthotic gait training compared to baseline. Comparison of injury level regarding gait parameters Table 3 demonstrates the alteration to walking parameters for the SCI subjects before and after orthotic gait training. The results demonstrated that patients with a higher level of SCI had lower walking speeds and shorter step lengths as compared to patients with a lower levels of SCI. Those subjects with lower mean values of gait parameters in this study experienced a more limited hip range of motion when using the orthosis and had a higher thoracic level of injury. These results corresponded with those demonstrated in previous studies [20,21]. Lateral and vertical compensatory motions The mean SD and range of these parameters before and after orthotic gait training are demonstrated in Tables 2 and 3. Gait training with the PHO improved lateral and vertical compensatory motions compared to baseline, but there was no significant difference between baseline and following orthotic gait training in these parameters (Table 2). Kinematics Hip angle Mean SD (range) of hip flexion/extension during baseline and after gait training with the PHO are demonstrated in Tables 2 and 3 and Figure 2. The maximum hip flexion and extension angles were 18.25 2.06 and 7.5 0.57 after gait training, but average flexion and extension angles were 10 5.22 and 6.25 0.95 in baseline when walking with PGO pre-gait training. There were no significant differences in flexion and extension parameters between walking with PGO pre and post gait training (p50.05) (Table 2).
Discussion The effect of gait training with the PHO on the kinematics and temporal spatial parameters in four SCI subjects was evaluated in
this study. The new powered orthosis PHO was able to provide dynamic hip joint movements during stance and swing phase of the gait cycle, without any falling and or balance problems being experienced by the volunteer subjects during the walking trials. However, it was found that hip joint kinematics and temporal spatial parameters (walking speed and step length) were not significantly improved by induction of activated hip joint motion. The low sample size (n ¼ 4) may have produced this result. During walking with the PHO orthosis, SCI patients used their trunk muscles to ambulate with the un-adapted mechanical orthosis. In this way, flexion of the trunk can cause excessive vertical and lateral compensatory motions. Gait training for at least 6 to 10 weeks with the powered gait orthosis reduced these compensatory motions compared to baseline. Reduction of compensatory motion can cause a reduction of energy consumption. High energy consumption and fatigue have been reported as one of the main reasons of rejection of mechanical orthosis use by SCI subjects [22]. Based on the reduction of compensatory motions demonstrated after gait training with the PHO, we can deduce that this PHO may reduce energy consumption when being used by SCI patients when compared to non-powered versions. However, this parameter was not evaluated in this study, and further studies regarding analysis of energy consumption will enable confirmation of this effect in this field of orthotic intervention. Activated motion in the orthotic hip joint in conjunction with walking training with the orthosis increased step length and walking speed in all of the subjects tested, and their pattern of sagittal plane hip motion more closely matched that of normal walking. The hip joint range of motions when walking with the PHO was still less than the mean of this parameters in normal human gait, but the overall pattern of hip joint movement was similar to a normal human pattern (Figure 2). However, the maximum extension angle of hip joint occurred much earlier compared to normal gait both during walking with PHO at baseline (30% of the gait cycle), and after orthotic gait training (45% of the gait cycle). The gait training with the orthosis demonstrated the positive effect of producing a hip flexion and extension pattern similar to that of normal walking. The reduction of mean of hip joint range of motion compared to normal value of this parameter may been due to the fact that both knees were fixed in extension and both ankles were placed in a neutral position within the orthosis. The available range of motion for lower limb joints when using the PHO were hip flexion (18.25 ), hip extension (7.5 ), knee flexion and extension (0 ), plantar flexion and dorsi flexion of ankle joint
DOI: 10.3109/17483107.2013.807442
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(0 ). Gait training demonstrated only timing improvements in hip joint kinematics and no effect on the mean flexion and extension of the hip joints. In comparison with previous studies in this field, the findings of this study demonstrated faster walking speeds and improvements in step length by SCI subjects compared to studies by Ohta et al. [6] when using powered hip and knee joints actuated separately, Kawashima et al. [23] when evaluating a WBCO with an activated foot plate, Leung et al. [24] in analysis of walking with an IRGO, plus studies by Mussucci et al. [25] and Ljzerman et al. [26]. These parameters were improved following the completion of the 10 weeks of gait training in this study. This study also investigated whether activated hip movement would improve kinematic and temporal spatial parameters in paraplegic patients. This is because activated hip movement would cause the afferent inputs to be sent from the muscles around the hip joint in the SCI patients. The present results therefore propose that the hip activated movement have a potential to support the neuromuscular performance in the paralysed lower limb. Activation of paralysed lower limb muscles has been reported in SCI patients when using rehabilitation via body weight supported rehabilitation [27–29] and walking with powered gait orthosis [16,17]. Harkema et al. [29] and Dietz et al. [30] reported inputs from lower limb loading and hip joint motion are critical role in generation of muscle activity in SCI patients. In this study the muscle activity of paralysed muscles was not evaluated and further studies in this field in evaluation of the effect of the PHO on this parameter will be beneficial in rehabilitation of SCI patients.
Conclusion This study evaluated the influence of gait training with a PHO on kinematics and temporal spatial parameters in paraplegic patients. This study demonstrated the new PGO improved hip joint motion patterns, increased walking speed and step length and decreased lateral and vertical compensatory motions during level-ground walking trials. This device may therefore be considered as an alternative device for providing gait training for paraplegic subjects.
Declaration of interest The authors do not have any conflicts of interest with regards to the study presented in this paper.
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