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The effect of fixed ankle–foot orthoses on spatio-temporal parameters, kinematics and muscle activity in children with spastic diplegia
Published posters / Gait & Posture 24S (2006) S98–S289
6. Discussion The results of the present study demonstrated that although the confounding factors had been taken in account, patients with a more severe knee OA tended to load their lower extremity less impulsively during walking. Furthermore, the less affected limb was exposed to a higher loading. These alterations in walking may serve as a part of the compensatory mechanisms in the course of the OA disease. Muscle pre-activation is proposed to be an important mechanism to protect the musculoskeletal system from potentially adverse impulsive loading during walking [4]. We did not find any correlation between muscle pre-activation and shock attenuation. The underlying knee OA could interfere with this association previously found when examining few healthy subjects [4].
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restoring the heel–toe gait, stabilising joints of the hindfoot, holding the skeleton of the foot in an anatomical position and controlling muscle tone and spasticity [1–3]. Abnormal muscle activity plays a major role in the abnormal gait patterns in CP, but only few studies have reported the effects of AFOs on muscle activity. Significant effects were found on peak activity [4], mean frequency and amplitude [5], whereas no effects of AFOs on the muscle timing were shown [6,7]. Whether AFOs have an effect on the excessive co-activation in children with CP has not been reported in the literature. The aim of this study was to determine the effects of clinically prescribed fixed AFOs on spatio-temporal parameters, kinematics, muscle amplitude and co-activation in children with spastic diplegic cerebral palsy (SCP).
3. Statement of clinical significance References [1] Radin EL, et al. In: Lantz SH, King AI, editors. Advances in bioengineering. 1986. p. 121–3. [2] Voloshin A, Wosk J. J Biomech 1982;15:21–7. [3] Childs JD, et al. Clin Biomech 2004;19:44–9. [4] Jefferson RJ, et al. Proc Inst Mech Eng 1990;204:21–8.
doi:10.1016/j.gaitpost.2006.11.102 PP-035 The effect of fixed ankle–foot orthoses on spatio-temporal parameters, kinematics and muscle activity in children with spastic diplegia Diana van Rooijen a,∗ , J. de Groot a , J. Harlaar a,b , A.P. Shortland c a
Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands b VU University Medical Center, Department of Rehabilitation Medicine, Amsterdam, The Netherlands c One Small Step Gait Laboratory, Guy’s Hospital, London, England
1. Summary/conclusions In a retrospective study, the effects of a fixed AFO on gait performance, kinematics and muscle activity were analysed in 12 children with spastic diplegia. Data of a standard gait analysis were analysed for a barefoot and AFO condition and compared to a control group. Fixed AFOs improved stride and step length, had small effects on muscle amplitude, and no effects on co-activation.
2. Introduction An ankle–foot orthosis (AFO) is commonly prescribed for children with CP and is believed to improve function by
AFOs do not alter the abnormal levels of co-activation of antagonist muscles observed in ambulant children with SCP during walking.
4. Methods Surface electromyography (EMG), spatio-temporal and kinematic (Vicon 370 six camera and 612 seven camera system) data collected from gait analyses at a single clinical laboratory of 12 children with spastic diplegia (mean age 11.1 years), were analysed retrospectively. Children were included if they walked independently, had no intervention within a year of the analysis, and if they regularly wore AFOs. Children always performed their barefoot walking trials first. Then, their usual AFOs were fitted avoiding displacement of the electromyographic sensors. Shank and foot retroflective markers were replaced. Barefoot and AFO trials were compared. The co-activation index (CI) between antagonist muscles was measured according to the method of Winter [8]. Co-activation of the medial hamstrings and m. rectus femoris (thigh CI) as well as from the m. tibialis anterior and m. gastrocnemius medialis (shank CI) was measured. Spatio-temporal parameters and the muscle co-activation of the barefoot condition were compared to a control group of typically developing children (13 children, mean age 8.8 years).
5. Results Compared to the control group, children with CP walked slower (p < 0.0001), with smaller strides (p < 0.0001) and with higher co-activation (p = 0.0001) than normally developing children. In children with CP, walking with an AFO significantly increased stride length (p = 0.0001), with a mean increase of 11 cm. Walking with AFOs decreased minimum hip flexion during stance by a mean of 2◦ (p = 0.004). The
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Published posters / Gait & Posture 24S (2006) S98–S289
amplitudes of m. rectus femoris and m. tibialis anterior decreased (p = 0.02 and 0.04, respectively) in the AFO condition, while the amplitude of the medial hamstrings increased (p = 0.03). The amplitude of m. gastrocnemius medialis did not show any changes and there were no changes in any of the separate phases of the gait cycle. No significant effects of AFOs on co-activation of the thigh or shank were found over the gait cycle. Analysis of the separate phases of the gait cycle showed a significant increase of the co-activation of the shank (11%) during loading.
6. Discussion The increase in stride length with 11 cm, is comparable to the amount of increase found in previous studies as a result of wearing fixed AFOs, ranging from 11 to 13 cm [2,7]. Changes in walking speed and cadence were not significant. This could be due to different individual adaptations to walking with AFOs, some of the children showed an increase in speed, whereas others decreased their cadence. The higher coactivation in thigh and shank muscles compared to the control group are in agreement with the literature and suggest an inefficient gait pattern and abnormal muscle activation [8–12]. Walking with an AFO showed no differences in co-activation of the shank and thigh in the CP children. Analysis of the separate phases of the gait cycle showed a significant increase of co-activation of the shank during loading. This indicates that fixed AFOs have little influence on co-activation. The AFOs had small effects on the EMG amplitude during the whole gait cycle. Our results suggest that fixed AFOs do not moderate the abnormal muscle activation patterns observed in children with SCP in the short-term. Longitudinal studies are required to investigate the long-term effects of orthoses on muscle activation. All the children wore prescribed AFOs, but no details for the prescription or the biomechanical alignment procedure were available. It is possible that AFO/footwear combinations modified after biomechanical alignment could result in greater improvements in gait and lower levels of co-activation [13].
References [1] Gage JR. The treatment of cerebral palsy. London: Mac Keith Press; 2004. [2] Brunner, et al. J Pediatr Orthop 1998;18(6):719–26. [3] Sussman MD. The diplegic child. Rosemont: American Academy of Orthopaedic Surgeons; 1992. [4] Romkes et al. Gait Posture, in press. [5] Lam, et al. Gait Posture 2005;22(3):189–97. [6] Rethlefsen, et al. J Pediatr Orthop 1999;19:470–4. [7] Radtka, et al. Gait Posture 2005;21:303–10. [8] Winter. Biomechanics and motor control of human movement. New York: John Wiley & Sons, Inc.; 1990. [9] Unnithan, et al. Med Sci Sports Exer 1996;28:1498–504. [10] Leonard. Dev Med Child Neurol 1991;33:567–77. [11] Unnithan, et al. Med Sci Sports Exer 1999;31(12):1703–15.
[12] Berger, et al. Electroencephologr Clin Neurophysiol 1982;53:538–48. [13] Owen E. Gait Posture 2005;22(Suppl. 1):36–7.
doi:10.1016/j.gaitpost.2006.11.103 PP-036 The effect of longitudinal compliance on amputee gait kinetics and knee kinematics Martin Twiste ∗ , Chris Nester, Laurence Kenney, Shyam Rithalia Centre for Rehabilitation and Human Performance Research, University of Salford, Salford, UK
1. Summary/conclusions The introduction of longitudinal compliance in a transtibial prosthesis was found to delay the lower limb peak vertical GRFs, knee flexion angle and knee flexion moment. This delay, in turn, was associated with a reduction in power absorption at the knee, which is likely to be of benefit in amputees with pain and/or degenerative diseases of the knee.
2. Introduction The most common reasons for lower extremity amputations are underlying pathologies that compromise the affected limb’s vascularity. Although pathologies of this nature can manifest themselves at any age, they are more common in older people, who often also suffer from co-morbidities, such as rheumatic diseases, which can particularly affect the knee. As the majority of lower extremity amputations occur at trans-tibial level, or below the knee, a significant number of amputees therefore experience knee pain when walking on a prosthesis. It has been shown that the prevalence of knee pain is 40.3% amongst amputees compared to 20.2% amongst nonamputees [1]. Although the prevalence of knee pain amongst amputees without rheumatic diseases appears to be higher in the non-amputated limb [1], it is likely that a more representative sample of patients may show a significant incidence of knee pain in the amputated limb. Also, as there is most likely an interaction between the non-amputated and amputated limb, prosthetic devices that influence the loading on the amputated limb will also likely influence the non-amputated limb, and hence warrant investigation. Prosthetic devices of this type are commonly mobile adapters with longitudinal compliance for a non-rigid connection between the socket and prosthetic foot [2]. Mobile adapters may help to reduce the magnitude and rate of loading on the knee by absorbing shock due to damping of early stance loads in response to longitudinal compliance. Here, we report on a study that initially focuses on the magnitude and rate of loading on the amputated side knee during early
6. Discussion The results of the present study demonstrated that although the confounding factors had been taken in account, patients with a more severe knee OA tended to load their lower extremity less impulsively during walking. Furthermore, the less affected limb was exposed to a higher loading. These alterations in walking may serve as a part of the compensatory mechanisms in the course of the OA disease. Muscle pre-activation is proposed to be an important mechanism to protect the musculoskeletal system from potentially adverse impulsive loading during walking [4]. We did not find any correlation between muscle pre-activation and shock attenuation. The underlying knee OA could interfere with this association previously found when examining few healthy subjects [4].
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restoring the heel–toe gait, stabilising joints of the hindfoot, holding the skeleton of the foot in an anatomical position and controlling muscle tone and spasticity [1–3]. Abnormal muscle activity plays a major role in the abnormal gait patterns in CP, but only few studies have reported the effects of AFOs on muscle activity. Significant effects were found on peak activity [4], mean frequency and amplitude [5], whereas no effects of AFOs on the muscle timing were shown [6,7]. Whether AFOs have an effect on the excessive co-activation in children with CP has not been reported in the literature. The aim of this study was to determine the effects of clinically prescribed fixed AFOs on spatio-temporal parameters, kinematics, muscle amplitude and co-activation in children with spastic diplegic cerebral palsy (SCP).
3. Statement of clinical significance References [1] Radin EL, et al. In: Lantz SH, King AI, editors. Advances in bioengineering. 1986. p. 121–3. [2] Voloshin A, Wosk J. J Biomech 1982;15:21–7. [3] Childs JD, et al. Clin Biomech 2004;19:44–9. [4] Jefferson RJ, et al. Proc Inst Mech Eng 1990;204:21–8.
doi:10.1016/j.gaitpost.2006.11.102 PP-035 The effect of fixed ankle–foot orthoses on spatio-temporal parameters, kinematics and muscle activity in children with spastic diplegia Diana van Rooijen a,∗ , J. de Groot a , J. Harlaar a,b , A.P. Shortland c a
Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands b VU University Medical Center, Department of Rehabilitation Medicine, Amsterdam, The Netherlands c One Small Step Gait Laboratory, Guy’s Hospital, London, England
1. Summary/conclusions In a retrospective study, the effects of a fixed AFO on gait performance, kinematics and muscle activity were analysed in 12 children with spastic diplegia. Data of a standard gait analysis were analysed for a barefoot and AFO condition and compared to a control group. Fixed AFOs improved stride and step length, had small effects on muscle amplitude, and no effects on co-activation.
2. Introduction An ankle–foot orthosis (AFO) is commonly prescribed for children with CP and is believed to improve function by
AFOs do not alter the abnormal levels of co-activation of antagonist muscles observed in ambulant children with SCP during walking.
4. Methods Surface electromyography (EMG), spatio-temporal and kinematic (Vicon 370 six camera and 612 seven camera system) data collected from gait analyses at a single clinical laboratory of 12 children with spastic diplegia (mean age 11.1 years), were analysed retrospectively. Children were included if they walked independently, had no intervention within a year of the analysis, and if they regularly wore AFOs. Children always performed their barefoot walking trials first. Then, their usual AFOs were fitted avoiding displacement of the electromyographic sensors. Shank and foot retroflective markers were replaced. Barefoot and AFO trials were compared. The co-activation index (CI) between antagonist muscles was measured according to the method of Winter [8]. Co-activation of the medial hamstrings and m. rectus femoris (thigh CI) as well as from the m. tibialis anterior and m. gastrocnemius medialis (shank CI) was measured. Spatio-temporal parameters and the muscle co-activation of the barefoot condition were compared to a control group of typically developing children (13 children, mean age 8.8 years).
5. Results Compared to the control group, children with CP walked slower (p < 0.0001), with smaller strides (p < 0.0001) and with higher co-activation (p = 0.0001) than normally developing children. In children with CP, walking with an AFO significantly increased stride length (p = 0.0001), with a mean increase of 11 cm. Walking with AFOs decreased minimum hip flexion during stance by a mean of 2◦ (p = 0.004). The
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Published posters / Gait & Posture 24S (2006) S98–S289
amplitudes of m. rectus femoris and m. tibialis anterior decreased (p = 0.02 and 0.04, respectively) in the AFO condition, while the amplitude of the medial hamstrings increased (p = 0.03). The amplitude of m. gastrocnemius medialis did not show any changes and there were no changes in any of the separate phases of the gait cycle. No significant effects of AFOs on co-activation of the thigh or shank were found over the gait cycle. Analysis of the separate phases of the gait cycle showed a significant increase of the co-activation of the shank (11%) during loading.
6. Discussion The increase in stride length with 11 cm, is comparable to the amount of increase found in previous studies as a result of wearing fixed AFOs, ranging from 11 to 13 cm [2,7]. Changes in walking speed and cadence were not significant. This could be due to different individual adaptations to walking with AFOs, some of the children showed an increase in speed, whereas others decreased their cadence. The higher coactivation in thigh and shank muscles compared to the control group are in agreement with the literature and suggest an inefficient gait pattern and abnormal muscle activation [8–12]. Walking with an AFO showed no differences in co-activation of the shank and thigh in the CP children. Analysis of the separate phases of the gait cycle showed a significant increase of co-activation of the shank during loading. This indicates that fixed AFOs have little influence on co-activation. The AFOs had small effects on the EMG amplitude during the whole gait cycle. Our results suggest that fixed AFOs do not moderate the abnormal muscle activation patterns observed in children with SCP in the short-term. Longitudinal studies are required to investigate the long-term effects of orthoses on muscle activation. All the children wore prescribed AFOs, but no details for the prescription or the biomechanical alignment procedure were available. It is possible that AFO/footwear combinations modified after biomechanical alignment could result in greater improvements in gait and lower levels of co-activation [13].
References [1] Gage JR. The treatment of cerebral palsy. London: Mac Keith Press; 2004. [2] Brunner, et al. J Pediatr Orthop 1998;18(6):719–26. [3] Sussman MD. The diplegic child. Rosemont: American Academy of Orthopaedic Surgeons; 1992. [4] Romkes et al. Gait Posture, in press. [5] Lam, et al. Gait Posture 2005;22(3):189–97. [6] Rethlefsen, et al. J Pediatr Orthop 1999;19:470–4. [7] Radtka, et al. Gait Posture 2005;21:303–10. [8] Winter. Biomechanics and motor control of human movement. New York: John Wiley & Sons, Inc.; 1990. [9] Unnithan, et al. Med Sci Sports Exer 1996;28:1498–504. [10] Leonard. Dev Med Child Neurol 1991;33:567–77. [11] Unnithan, et al. Med Sci Sports Exer 1999;31(12):1703–15.
[12] Berger, et al. Electroencephologr Clin Neurophysiol 1982;53:538–48. [13] Owen E. Gait Posture 2005;22(Suppl. 1):36–7.
doi:10.1016/j.gaitpost.2006.11.103 PP-036 The effect of longitudinal compliance on amputee gait kinetics and knee kinematics Martin Twiste ∗ , Chris Nester, Laurence Kenney, Shyam Rithalia Centre for Rehabilitation and Human Performance Research, University of Salford, Salford, UK
1. Summary/conclusions The introduction of longitudinal compliance in a transtibial prosthesis was found to delay the lower limb peak vertical GRFs, knee flexion angle and knee flexion moment. This delay, in turn, was associated with a reduction in power absorption at the knee, which is likely to be of benefit in amputees with pain and/or degenerative diseases of the knee.
2. Introduction The most common reasons for lower extremity amputations are underlying pathologies that compromise the affected limb’s vascularity. Although pathologies of this nature can manifest themselves at any age, they are more common in older people, who often also suffer from co-morbidities, such as rheumatic diseases, which can particularly affect the knee. As the majority of lower extremity amputations occur at trans-tibial level, or below the knee, a significant number of amputees therefore experience knee pain when walking on a prosthesis. It has been shown that the prevalence of knee pain is 40.3% amongst amputees compared to 20.2% amongst nonamputees [1]. Although the prevalence of knee pain amongst amputees without rheumatic diseases appears to be higher in the non-amputated limb [1], it is likely that a more representative sample of patients may show a significant incidence of knee pain in the amputated limb. Also, as there is most likely an interaction between the non-amputated and amputated limb, prosthetic devices that influence the loading on the amputated limb will also likely influence the non-amputated limb, and hence warrant investigation. Prosthetic devices of this type are commonly mobile adapters with longitudinal compliance for a non-rigid connection between the socket and prosthetic foot [2]. Mobile adapters may help to reduce the magnitude and rate of loading on the knee by absorbing shock due to damping of early stance loads in response to longitudinal compliance. Here, we report on a study that initially focuses on the magnitude and rate of loading on the amputated side knee during early