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Improvement of knee extension in terminal swing in very young children with cerebral palsy after injection of botulinum toxin
Abstracts / Gait & Posture 39S (2014) S1–S141
A (DS: p = 0.01). Consequently BTX-A induced more dorsiflexion at the start of push off (v2: p < 0.001, DS: p < 0.05). Maximum muscle length (ML) in stance was significantly higher post BTX-A at both velocities (v1: p < 0.01, v2: p = 0.001, no significant DS). Maximum ML occurred earlier pre vs. post BTX-A with increasing WV (DS: p < 0.05). There was significantly less increase in EMG activity in early stance and the entire stance phase post BTX-A (DS: p < 0.05). The third rocker was characterised by increased plantar flexion velocity with increasing WV, however this pattern was significantly less pronounced post BTX-A compared to pre BTX-A (DS: p < 0.05). In swing, better position at mid- and terminal swing was observed post BTX-A at both velocities (p = 0.001, no significant DS). Hamstrings treated group (N = 20). Position at IC was significantly better post BTX-A at v1 (p < 0.05) and v2 (p = 0.005, but no significant DS). Maximum knee extension in stance was significantly better post BTX-A at v2 (p < 0.05), resulting in a trend of improved knee extension with increasing WV post BTX-A, compared to increased flexion pre BTX-A. Increased knee extension resulted in increased ROM in stance post BTX-A compared to pre BTX-A (v1 and v2: p < 0.05). In swing, maximum ML improved with BTX-A at both velocities (v1: p < 0.05, v2: p < 0.001), but with similar effects of WV. No difference was found on maximum muscle lengthening velocity (MLV) and EMG activity between both conditions. Discussion and conclusions: Children treated with BTX-A in gastrocnemius presented with decreased MLV at IC and loading response, allowing a more normalized second rocker. BTX-A in the gastrocnemius primarily reduces spasticity [4] and additionally less spasticity is provoked by reducing MLV and improving gait. This was confirmed by less increase in EMG activity post BTX-A with increasing WV. These results confirm the effect of BTX-A during early stance, which was previously described as being sensitive to increased WV [2]. BTX-A in the hamstrings induced improved knee kinematics at IC and midstance, resulting in improved ROM. However, these improvements were less sensitive to WV. Due to the biomechanical demands, tone reduction in the hamstrings is less reflected in velocity dependent gait parameters. This was also described in the study which compared the effect of increased WV in spastic versus non spastic hamstrings [3]. Reference [1] [2] [3] [4]
Van der Krogt, et al. Gait Posture 2007 and2009. Huenaerts, et al. ESMAC Vienna; 2011. Huenaerts, et al. ESMAC Stockholm 2012. Molenaers, et al. J Child Orthop 2010.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.089
S65
085 Improvement of knee extension in terminal swing in very young children with cerebral palsy after injection of botulinum toxin ˛ Marcin Bonikowski 1,∗ , Gasior Jakub 1,2 , 1,2,3 Pawłowski Mariusz 1 Mazovian Centre of Neuropsychiatry in Zagórze near Warsaw, Poland 2 Medical University of Warsaw, Cardiology Clinic of Physiotherapy Division of The 2nd Faculty 3 Józef Piłsudski University of Physical Education in Warsaw, Faculty of Rehabilitation
Introduction and aim: Muscle shortening secondary to spasticity develops in time in children with spastic CP and causes gait deviations. Reduced knee extension in terminal swing is often related to static and dynamic shortening of hamstring muscles. Botulinum toxin type A (BoNT-A) injection is a recommended treatment for muscle over-activity in children with cerebral palsy [1]. Video gait analysis (VGA) has been widely used in research studies investigating the use of BoNT-A for gait dysfunction in children with CP. The aim of this study was to assess the outcome of BoNT-A injection into hamstring muscles with emphasis on the changes in the knee extension in terminal swing (KE TSw). Patients/materials and methods: Popliteal angle – passive range of motion (PROM) and angle of catch (AOC) in the lower extremities were analyzed along with abnormalities of knee extension in terminal swing phases of gait in 13 consecutive children (26 extremities) with bilateral CP GMFCS II-IV selected for BoNTA treatment before the age of 3 years. Data was collected before and after the BoNT-A treatment. All the children received BoNT-A Botox injections into Semitendinosus, Semimembranosus and Gracilis muscles. For the knee extension measurement 2D video was used with on screen goniometry. All children participated in regular physiotherapy and wore AFOs min. six hours a day. Results: At the time of administration of BoNT-A mean age was 2 years 6 months (±4 months; 25–36). 31% of children (n = 4) were rated as level II, 38% (n = 5) as the level III, and 31% (n = 4) as the level IV of GMFCS. According to Amsterdam gait Classification [2] 31% (n = 8) limbs were classified as 2, 38% (n = 10) as 3, 15% (n = 4) as 4 and 15% (n = 4) as 5. The average duration of the period of time between the administration of BoNT-A and second physical examination and gait analysis lasted 181 days (±71, 94–315). The knees showed significant benefits, as evidenced by improved maximal knee extension in swing phase from – 45 degree (±11; 21–69) pre BoNT-A to −39 degree (±12; 12–71) post BTX (p = 0.011). GMFCS II group improved most. Popliteal angle changed from 43 (±16; 10–70) to 46 (±19; 20–80) p = 0.64 for PROM and from 83 (±21; 0–100) to 79 (±15, 35–100) p = 0.20 for AOC respectively. There was a significant correlation between time from injection and KE TSw (r = 0.42, p < 0.05) and between PROM and KE TSw (r = −0.43, p < 0.05). Discussion and conclusions: This is a part of a bigger study in which we focus on treatment outcomes in youngest group of children referred to our centre for botulinum toxin treatment. Treatment of spasticity in combination with physiotherapy and orthotic management shows influence on the knee extension in terminal swing in the study group.
S66
Abstracts / Gait & Posture 39S (2014) S1–S141
Reference [1] Love SC, Novak I, Kentish M, Desloovere K, Heinen F, Molenaers G, O’Flaherty S, Graham HK. Botulinum toxin assessment, intervention and after-care for lower limb spasticity in children with cerebral palsy: international consensus statement. Eur J Neurol 2010;17(Suppl. 2):9–37. [2] Becher JG. Pediatric Rehabilitation in Children with Cerebral Palsy: General Management, Classification of Motor Disorders. JPO 2002;14:143–9.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.090 086
Session 5B: Foot
Integrating a multi-segment foot model in simulation of gait to better understand plantar pressure distribution Wouter Aerts 1,∗ , Josefien Burg 1,2 , Friedl De Groote 3 , Jos Vander Sloten 1 , Ilse Jonkers 2 1
Department of Mechanical Engineering, Biomechanics section, KU Leuven, Belgium 2 Department of Kinesiology, Human movement biomechanics, KU Leuven, Belgium 3 Department of Mechanical Engineering, PMA, KU Leuven, Belgium Introduction and aim: 3D gait analysis using motion capture has proven its usefulness and its effectiveness in examining pathological gait, and evaluating surgical and rehabilitation treatments. Gait analysis is based on a biomechanical multi-body model and the number of degrees of freedom (DOF) of this model has increased over the years in order to increase the accuracy of the kinematic description. However, for simulation purposes the 1-DOF foot model is still mostly used. The aim of this study is 1) to use a multi-segment foot model to simulate the plantar pressure during gait and 2) to compare the results with a one-segment foot model. Patients/materials and methods: The gait pattern of a subject walking barefoot is measured in a gait lab (MALL, Movement & posture Analysis Laboratory Leuven, 10 Vicon cameras, 2 AMTI-force plates, 2 RSscan pressure plates). Additional markers were placed on the foot, in order to distinguish 5 foot segments (hindfoot, midfoot, lateral & medial forefoot, and hallux). Based on the recorded marker data, gait is simulated in OpenSim [1,2], using two different musculoskeletal models, one with a 1-DOF foot model (ankle joint) and the second one with a 3-DOF foot model (ankle, subtalar, and metatarsophalangeal joint). Inverse Kinematics, Residual Reduction Algorithm, and Computed Muscle Control were consequently applied to calculate the muscle controls underlying the
measured gait motion. The calculated controls were input to a forward dynamic simulation that predicted the resulting GRF based on an elastic foundation (EF) contact model. It describes the contact forces between the foot and the ground based on the indentation of a contact geometry within the floor [3,4]. The outer surface of a foot, retrieved from CT-images, is used as contact geometry. For the 3-DOF foot this contact geometry is separated into two parts, as shown in Fig. 1. Results: Fig. 2 shows the maximal plantar pressure calculated by the forward dynamic simulation from mid-stance to swing, using two different foot models (a and b). A qualitative comparison with the measured plantar pressure (c) shows a better correspondence for the 3-DOF foot then for the 1-DOF foot. For example, the high pressure region at the lateral side of the metatarsal arch is correctly simulated by the 3-DOF foot model but not by the 1-DOF foot model. The center of pressure path of the 3-DOF foot simulation resembles nicely the measured path. Discussion and conclusions: The proposed workflow shows how the plantar pressure can be simulated using an EF contact model. Contrary to finite elements, this method is not limited to quasi-static situations and hence, gait simulation can be performed within a reasonable calculation time enabling evaluation and optimization of shoes, insoles or orthotics design, performed on a computer. It is also shown that incorporating more DOF for the
Fig. 1. 3-DOF foot with a separate contact mesh for the toes and the rest of the foot.
Fig. 2. Peak plantar pressure for a simulation with (a) a 1-DOF foot; (b) a 3-DOF foot compared with (c) the measured pressure. The black dots indicate the COP.
A (DS: p = 0.01). Consequently BTX-A induced more dorsiflexion at the start of push off (v2: p < 0.001, DS: p < 0.05). Maximum muscle length (ML) in stance was significantly higher post BTX-A at both velocities (v1: p < 0.01, v2: p = 0.001, no significant DS). Maximum ML occurred earlier pre vs. post BTX-A with increasing WV (DS: p < 0.05). There was significantly less increase in EMG activity in early stance and the entire stance phase post BTX-A (DS: p < 0.05). The third rocker was characterised by increased plantar flexion velocity with increasing WV, however this pattern was significantly less pronounced post BTX-A compared to pre BTX-A (DS: p < 0.05). In swing, better position at mid- and terminal swing was observed post BTX-A at both velocities (p = 0.001, no significant DS). Hamstrings treated group (N = 20). Position at IC was significantly better post BTX-A at v1 (p < 0.05) and v2 (p = 0.005, but no significant DS). Maximum knee extension in stance was significantly better post BTX-A at v2 (p < 0.05), resulting in a trend of improved knee extension with increasing WV post BTX-A, compared to increased flexion pre BTX-A. Increased knee extension resulted in increased ROM in stance post BTX-A compared to pre BTX-A (v1 and v2: p < 0.05). In swing, maximum ML improved with BTX-A at both velocities (v1: p < 0.05, v2: p < 0.001), but with similar effects of WV. No difference was found on maximum muscle lengthening velocity (MLV) and EMG activity between both conditions. Discussion and conclusions: Children treated with BTX-A in gastrocnemius presented with decreased MLV at IC and loading response, allowing a more normalized second rocker. BTX-A in the gastrocnemius primarily reduces spasticity [4] and additionally less spasticity is provoked by reducing MLV and improving gait. This was confirmed by less increase in EMG activity post BTX-A with increasing WV. These results confirm the effect of BTX-A during early stance, which was previously described as being sensitive to increased WV [2]. BTX-A in the hamstrings induced improved knee kinematics at IC and midstance, resulting in improved ROM. However, these improvements were less sensitive to WV. Due to the biomechanical demands, tone reduction in the hamstrings is less reflected in velocity dependent gait parameters. This was also described in the study which compared the effect of increased WV in spastic versus non spastic hamstrings [3]. Reference [1] [2] [3] [4]
Van der Krogt, et al. Gait Posture 2007 and2009. Huenaerts, et al. ESMAC Vienna; 2011. Huenaerts, et al. ESMAC Stockholm 2012. Molenaers, et al. J Child Orthop 2010.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.089
S65
085 Improvement of knee extension in terminal swing in very young children with cerebral palsy after injection of botulinum toxin ˛ Marcin Bonikowski 1,∗ , Gasior Jakub 1,2 , 1,2,3 Pawłowski Mariusz 1 Mazovian Centre of Neuropsychiatry in Zagórze near Warsaw, Poland 2 Medical University of Warsaw, Cardiology Clinic of Physiotherapy Division of The 2nd Faculty 3 Józef Piłsudski University of Physical Education in Warsaw, Faculty of Rehabilitation
Introduction and aim: Muscle shortening secondary to spasticity develops in time in children with spastic CP and causes gait deviations. Reduced knee extension in terminal swing is often related to static and dynamic shortening of hamstring muscles. Botulinum toxin type A (BoNT-A) injection is a recommended treatment for muscle over-activity in children with cerebral palsy [1]. Video gait analysis (VGA) has been widely used in research studies investigating the use of BoNT-A for gait dysfunction in children with CP. The aim of this study was to assess the outcome of BoNT-A injection into hamstring muscles with emphasis on the changes in the knee extension in terminal swing (KE TSw). Patients/materials and methods: Popliteal angle – passive range of motion (PROM) and angle of catch (AOC) in the lower extremities were analyzed along with abnormalities of knee extension in terminal swing phases of gait in 13 consecutive children (26 extremities) with bilateral CP GMFCS II-IV selected for BoNTA treatment before the age of 3 years. Data was collected before and after the BoNT-A treatment. All the children received BoNT-A Botox injections into Semitendinosus, Semimembranosus and Gracilis muscles. For the knee extension measurement 2D video was used with on screen goniometry. All children participated in regular physiotherapy and wore AFOs min. six hours a day. Results: At the time of administration of BoNT-A mean age was 2 years 6 months (±4 months; 25–36). 31% of children (n = 4) were rated as level II, 38% (n = 5) as the level III, and 31% (n = 4) as the level IV of GMFCS. According to Amsterdam gait Classification [2] 31% (n = 8) limbs were classified as 2, 38% (n = 10) as 3, 15% (n = 4) as 4 and 15% (n = 4) as 5. The average duration of the period of time between the administration of BoNT-A and second physical examination and gait analysis lasted 181 days (±71, 94–315). The knees showed significant benefits, as evidenced by improved maximal knee extension in swing phase from – 45 degree (±11; 21–69) pre BoNT-A to −39 degree (±12; 12–71) post BTX (p = 0.011). GMFCS II group improved most. Popliteal angle changed from 43 (±16; 10–70) to 46 (±19; 20–80) p = 0.64 for PROM and from 83 (±21; 0–100) to 79 (±15, 35–100) p = 0.20 for AOC respectively. There was a significant correlation between time from injection and KE TSw (r = 0.42, p < 0.05) and between PROM and KE TSw (r = −0.43, p < 0.05). Discussion and conclusions: This is a part of a bigger study in which we focus on treatment outcomes in youngest group of children referred to our centre for botulinum toxin treatment. Treatment of spasticity in combination with physiotherapy and orthotic management shows influence on the knee extension in terminal swing in the study group.
S66
Abstracts / Gait & Posture 39S (2014) S1–S141
Reference [1] Love SC, Novak I, Kentish M, Desloovere K, Heinen F, Molenaers G, O’Flaherty S, Graham HK. Botulinum toxin assessment, intervention and after-care for lower limb spasticity in children with cerebral palsy: international consensus statement. Eur J Neurol 2010;17(Suppl. 2):9–37. [2] Becher JG. Pediatric Rehabilitation in Children with Cerebral Palsy: General Management, Classification of Motor Disorders. JPO 2002;14:143–9.
http://dx.doi.org/10.1016/j.gaitpost.2014.04.090 086
Session 5B: Foot
Integrating a multi-segment foot model in simulation of gait to better understand plantar pressure distribution Wouter Aerts 1,∗ , Josefien Burg 1,2 , Friedl De Groote 3 , Jos Vander Sloten 1 , Ilse Jonkers 2 1
Department of Mechanical Engineering, Biomechanics section, KU Leuven, Belgium 2 Department of Kinesiology, Human movement biomechanics, KU Leuven, Belgium 3 Department of Mechanical Engineering, PMA, KU Leuven, Belgium Introduction and aim: 3D gait analysis using motion capture has proven its usefulness and its effectiveness in examining pathological gait, and evaluating surgical and rehabilitation treatments. Gait analysis is based on a biomechanical multi-body model and the number of degrees of freedom (DOF) of this model has increased over the years in order to increase the accuracy of the kinematic description. However, for simulation purposes the 1-DOF foot model is still mostly used. The aim of this study is 1) to use a multi-segment foot model to simulate the plantar pressure during gait and 2) to compare the results with a one-segment foot model. Patients/materials and methods: The gait pattern of a subject walking barefoot is measured in a gait lab (MALL, Movement & posture Analysis Laboratory Leuven, 10 Vicon cameras, 2 AMTI-force plates, 2 RSscan pressure plates). Additional markers were placed on the foot, in order to distinguish 5 foot segments (hindfoot, midfoot, lateral & medial forefoot, and hallux). Based on the recorded marker data, gait is simulated in OpenSim [1,2], using two different musculoskeletal models, one with a 1-DOF foot model (ankle joint) and the second one with a 3-DOF foot model (ankle, subtalar, and metatarsophalangeal joint). Inverse Kinematics, Residual Reduction Algorithm, and Computed Muscle Control were consequently applied to calculate the muscle controls underlying the
measured gait motion. The calculated controls were input to a forward dynamic simulation that predicted the resulting GRF based on an elastic foundation (EF) contact model. It describes the contact forces between the foot and the ground based on the indentation of a contact geometry within the floor [3,4]. The outer surface of a foot, retrieved from CT-images, is used as contact geometry. For the 3-DOF foot this contact geometry is separated into two parts, as shown in Fig. 1. Results: Fig. 2 shows the maximal plantar pressure calculated by the forward dynamic simulation from mid-stance to swing, using two different foot models (a and b). A qualitative comparison with the measured plantar pressure (c) shows a better correspondence for the 3-DOF foot then for the 1-DOF foot. For example, the high pressure region at the lateral side of the metatarsal arch is correctly simulated by the 3-DOF foot model but not by the 1-DOF foot model. The center of pressure path of the 3-DOF foot simulation resembles nicely the measured path. Discussion and conclusions: The proposed workflow shows how the plantar pressure can be simulated using an EF contact model. Contrary to finite elements, this method is not limited to quasi-static situations and hence, gait simulation can be performed within a reasonable calculation time enabling evaluation and optimization of shoes, insoles or orthotics design, performed on a computer. It is also shown that incorporating more DOF for the
Fig. 1. 3-DOF foot with a separate contact mesh for the toes and the rest of the foot.
Fig. 2. Peak plantar pressure for a simulation with (a) a 1-DOF foot; (b) a 3-DOF foot compared with (c) the measured pressure. The black dots indicate the COP.