- Email: [email protected]
Optimizing knee kinematics in mid-stance by tuning the ankle foot orthoses-footwear combination of children with cerebral palsy: A case series
S88
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
Fig. 1. Contributions from the hip, knee and ankle joint to total positive work (mean percent) in AMC1, AMC2 and AMC3 groups and in the control group.
dren median age 9.7 (5.1–17.6) years. Children walked at a self-selected pace along a 10-m walkway with two force plates (Kistler©). Joint angles, moments, and work (time integral of power) were computed. Children with AMC were divided into 3 groups based on the type of custom-made orthosis prescribed with respect to individual deformity and muscle weakness; AMC1 used knee–ankle–foot orthosis (KAFO) with locked knee joints (n = 5), AMC2 used KAFOs with open knee joints or anklefoot orthosis (AFO) (n = 10), and AMC3 used shoes (n = 11). Non-parametric tests were used to compare results between groups. Results: Joint work analysis showed a proximal work shift in all AMC groups wherein the hip accounted for a larger portion of lower extremity positive work than the ankle or knee, primarily in AMC1 (Fig. 1). Hip abduction moment was lower in AMC1 and AMC2 than in TD, though not significantly. Trunk lateral sway and trunk rotation were greater in AMC1 and AMC2 than in AMC3 and TD. Hip flexion moment was lower in AMC1 than in other groups. Less hip extension and greater pelvic tilt were found in all AMC groups than in TD. Knee extension moments were similar between the groups. Discussion: The gait pattern with excessive trunk lateral sway in children walking with orthoses, particularly locked KAFOs, reduces the hip abduction moments. All AMC groups showed less hip extension than TD, but hip flexion moments were reduced only in AMC1, which can be attributed to their gait strategy with bilateral locked KAFOs. Children in AMC1, with weak knee extensors, were helped by their locked KAFOs and therefore showed similar knee extension moment as other groups. The joint work analysis demonstrates AMC children’s high reliance on hip muscles and presumably trunk muscles to provide propulsion, primarily in those walking with locked KAFOs. References [1] Hall J. J Ped Orthop 1997. [2] Eriksson M, et al. J Child Orthop 2010.
with respect to knee flexion during weight bearing [1] which is important to physiologically execute many activities of daily living (ADL). Therefore, the orthotronic mobility system C-Brace was developed employing microprocessor hydraulic stance and swing control. Materials and methods: Two patients using a locked KAFO (LKAFO; one unilateral, one bilateral) and four patients using a stance control orthosis (SCO) for walking were investigated. Tests were conducted with the existing orthosis (baseline) and after a minimum of 7 weeks of C-Brace use. The tests comprised level walking, descending a slope of 10◦ grade, and a stairwell. The measuring technique consisted of two force plates for recording the ground reaction forces (Kistler, sampling rate 1080 Hz) and an optoelectronic 6 camera system for determining kinematic data (Vicon 460, sampling rate 120 Hz). Based on kinematic data and ground reaction forces, the joint moments were calculated [2]. Results: During level walking, the mean time-distanceparameters do not show any significant differences, but 5 of the 6 patients were able to use knee stance flexion (mean knee angle 11◦ ) when using the C-Brace. The mean knee swing flexion angle was 66.6◦ with the C-Brace as compared to 74.0◦ with the SCOs. With the C-Brace, the sound side external joint moments are significantly reduced compared to the LKAFO condition, but do not differ from those with the SCO. With the C-Brace all six patients were able to descend the slope and stairs step over step. Only four patients were able to reciprocally descend the slope, no patient was able to do this on the stairs when using their previous devices. All patients used continuous knee flexion during weight bearing (mean maximum flexion on the slope 65◦ , on the stairs 70◦ ) with the C-Brace. The abnormally high knee extension moments that are unavoidable at ground contact of the sound limb when descending a slope with a SCO/LKAFO were reduced with the C-Brace. Discussion: The present study confirms that the microprocessor hydraulic control of stance and swing phase in the C- Brace supports nearly natural movement patterns on the orthotic side during level walking (use of stance phase flexion, control of swing phase flexion close to the physiological value) as well as controlled knee flexion during weight bearing that offers the patient remarkably increased functional options for walking on slopes and stairs. The nearly natural movement patterns allowed for by the C-Brace suggest that the loads acting on the locomotor system are qualitatively similar to those in healthy individuals. References [1] Zacharias B, Kannenberg A. J Prosth Orthot 2012;24. [2] Bellmann M, et al. Arch Phys Med Rehabil 2010;91:3.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.160 http://dx.doi.org/10.1016/j.gaitpost.2015.06.161
Session OS18 Orthotics The microprocessor controlled C-Brace orthosis and conventional knee–ankle–foot-orthoses: Comparative biomechanical evaluation of functionality T. Schmalz ∗ , E. Pröbsting Ottobock Healthcare, Clinical Research/Biomechanics, Göttingen, Germany Research question: Conventional KAFOs are compared to the C-Brace based on biomechanical parameters measured in ADL situations. Introduction: Patients with pareses or paralysis of the lower limbs often require a knee ankle foot orthosis (KAFO) to restore walking ability. Conventional KAFOs are limited in functionality
Session OS18 Orthotics Optimizing knee kinematics in mid-stance by tuning the ankle foot orthoses-footwear combination of children with cerebral palsy: A case series B. van Beeten 1,∗ , A. Hartman 2 , H. Houdijk 1 1
Rehabilitation Centre Heliomare, Wijk aan Zee, Netherlands 2 Erasmus MC, Rotterdam, Netherlands Research question: Is it necessary and possible to optimize knee kinematics in mid-stance by tuning the ankle foot orthosesfootwear combination of children with cerebral palsy?
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
Introduction: Rigid ankle foot orthoses (AFOs) are commonly used in children with spastic cerebral palsy (CP) to improve gait. The effectiveness of the AFO depends on the type of footwear around the AFO and whether the AFO-footwear combination (AFO-FC) is optimally tuned. Tuning involves making fine adjustments to the alignment of the AFO-FC in order to optimize the kinetics and kinematics of gait [1]. Despite the emerging evidence on the effect of AFO-FC tuning, limited studies exist on the necessity and efficacy of AFO-FC tuning in clinical practice [2]. In this case series we investigated the number of children requiring tuning after provision of an AFO-FC and whether this had a positive effect on their gait pattern. Materials and methods: Ambulatory children with bilateral or unilateral spastic CP aged between 3 and 18 years, who used a rigid AFO or floor reaction orthoses (FRO) to improve walking ability were included in the study. Children with dyskinetic or ataxic CP or who had severe cognitive limitations were excluded. Gait analysis was carried out in a gait analysis laboratory using a 2D video system (BTS, Milan, Italy). Each child walked at their own walking pace on the walkway, barefoot and with their non-tuned AFO-FC. Subsequently, they walked with four predefined alterations to AFOFC alignment: with a 0.5, 1.0, 1.5 cm heel wedge in the shoe or a stiff carbon plate in the shoe underneath the AFO. To explore the necessity and potential to optimize AFO-FC alignment, knee kinematics in mid-stance were assessed and compared in the non-tuned and tuned AFO-FC conditions. A change of >5 degrees knee angle towards the reference knee angle in midstance was considered a clinically relevant improvement. Results: Six boys and four girls mean age 8.5 (sd 4.7) years were included in the study. Eight had bilateral spastic CP and two had unilateral spastic CP. Nine children did not have an optimal knee angle (0–10 degrees knee flexion) in mid-stance during walking with non-tuned AFO-FC. After tuning the AFO-FC with wedges or the carbon plate the knee angle changed >5 degrees towards normal in six of them. In four children knee flexion and in two children knee hyperextension was diminished. Discussion: This study reveals that it is necessary and possible to tune the AFO-FC in children with CP in clinical practice to optimize knee kinematics in mid-stance. Subsequent effects on gait performance needs to be established. References [1] Owen E. MSc thesis. Child Development Centre; 2004. [2] Eddison N, et al. Prosthet Orthot Int 2012;37(2):95–107.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.162
S89
Session OS18 Orthotics The effects of different degrees of ankle foot orthosis stiffness on gait biomechanics and walking energy cost Y. Kerkum ∗ , J. Harlaar, J. van den Noort, J. Becher, A. Buizer, M.-A. Brehm Rehabilitation Medicine, VU University Medical Center, MOVE Research Institute Amsterdam, Amsterdam, Netherlands Research question: To investigate the effects of different degrees of ankle foot orthosis stiffness on knee and ankle parameters and gait efficiency in children with CP. Introduction: Gait of children with cerebral palsy (CP) is often hampered by excessive knee flexion. To counteract the knee flexion, ankle foot orthoses (AFOs) are commonly prescribed. The effect of an AFO on normalizing knee biomechanics may partly be dependent on its stiffness. While stiffer AFOs may normalize knee kine(ma)tics most effectively, very stiff AFOs obstruct ankle range of motion and push-off power, subsequently reducing gait efficiency. A more spring-like AFO may enhance push-off power, but might be less effective in counteracting knee flexion. Yet, a trade- off between normalization of knee kine(ma)tics and enhancing push-off power might optimize gait efficiency [1]. Materials and methods: 15 children with spastic CP (11 boys, 10 ± 2 years, GMFCS level I–III), all walking with excessive knee flexion, were prescribed with a ventral shell AFO with integrated hinge (Neuro Swing® , Fior & Gentz). The hinge was set into three stiffness configurations; rigid (3.8 Nm/deg), stiff (1.6 Nm/deg), and flexible (0.7 Nm/deg). At baseline (shoes-only) and for each AFO stiffness configuration, a 3D-gait analysis and walking energy cost test at comfortable speed were performed. We assessed peak knee extension during single support (KEpk), internal knee flexion moment at timing of KEpk (Mknee), ankle range of motion (RoM), and peak ankle power generation (A2). From the walking energy cost test, the net energy cost (n-EC) was determined. Generalized estimation equations (GEE) were used to analyze the effects of different conditions on all outcome measures. Results: Compared to shoes-only, all AFOs similarly improved KEpk and Mknee. All AFOs reduced ankle RoM, with higher stiffness levels showing less RoM. Peak ankle power generation was preserved with the spring-like AFOs (stiff and flexible), while the rigid AFO reduced push-off power. All AFOs significantly improved n-EC, while speed was not affected by AFOs (see Table 1). Discussion: All AFOs showed comparable improvements in the knee flexion angle and internal knee moment. However, springlike AFOs only showed favorable effects on the ankle RoM and power generation, compared to a rigid AFO. ECnet improvements were comparable for all AFOs. These results suggest that improved peak knee extension angle in stance is more important than enhancing push-off power to achieve walking energy
Table 1 Results of GEE analyses for gait biomechanics, speed and energy cost.
KEpk (deg) Mknee (Nm/kg) RoM (deg) A2 (W/kg) Speed (m/min) n-EC (J/kg/m)
Shoes (N = 15) Mean (SD)
Rigid (N = 14) Mean (SD)
Stiff (N = 15) Mean (SD)
Flexible (N = 14) Mean (SD)
P
Post-hoc
22.7 (8.7) 0.02 (0.18) 35.4 (8.1) 1.49 (0.71) 58.6 (11.3) 6.1 (1.7)
16.7 (10.0) −0.21 (0.23) 7.0 (2.4) 0.73 (0.30) 57.8 (8.0) 5.5 (1.1)
18.1 (8.6) −0.13 (0.18) 15.4 (4.3) 1.21 (0.43) 57.5 (8.4) 5.4 (1.2)
18.4 (9.3) −0.09 (0.18) 19.5 (3.9) 1.43 (0.53) 58.8 (7.4) 5.6 (1.5)
<0.001 <0.001 <0.001 <0.001 0.675 0.008
sh-r/s/f sh-r/s/f; r-f all conditions sh-r/s/f sh-r/s/f
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
Fig. 1. Contributions from the hip, knee and ankle joint to total positive work (mean percent) in AMC1, AMC2 and AMC3 groups and in the control group.
dren median age 9.7 (5.1–17.6) years. Children walked at a self-selected pace along a 10-m walkway with two force plates (Kistler©). Joint angles, moments, and work (time integral of power) were computed. Children with AMC were divided into 3 groups based on the type of custom-made orthosis prescribed with respect to individual deformity and muscle weakness; AMC1 used knee–ankle–foot orthosis (KAFO) with locked knee joints (n = 5), AMC2 used KAFOs with open knee joints or anklefoot orthosis (AFO) (n = 10), and AMC3 used shoes (n = 11). Non-parametric tests were used to compare results between groups. Results: Joint work analysis showed a proximal work shift in all AMC groups wherein the hip accounted for a larger portion of lower extremity positive work than the ankle or knee, primarily in AMC1 (Fig. 1). Hip abduction moment was lower in AMC1 and AMC2 than in TD, though not significantly. Trunk lateral sway and trunk rotation were greater in AMC1 and AMC2 than in AMC3 and TD. Hip flexion moment was lower in AMC1 than in other groups. Less hip extension and greater pelvic tilt were found in all AMC groups than in TD. Knee extension moments were similar between the groups. Discussion: The gait pattern with excessive trunk lateral sway in children walking with orthoses, particularly locked KAFOs, reduces the hip abduction moments. All AMC groups showed less hip extension than TD, but hip flexion moments were reduced only in AMC1, which can be attributed to their gait strategy with bilateral locked KAFOs. Children in AMC1, with weak knee extensors, were helped by their locked KAFOs and therefore showed similar knee extension moment as other groups. The joint work analysis demonstrates AMC children’s high reliance on hip muscles and presumably trunk muscles to provide propulsion, primarily in those walking with locked KAFOs. References [1] Hall J. J Ped Orthop 1997. [2] Eriksson M, et al. J Child Orthop 2010.
with respect to knee flexion during weight bearing [1] which is important to physiologically execute many activities of daily living (ADL). Therefore, the orthotronic mobility system C-Brace was developed employing microprocessor hydraulic stance and swing control. Materials and methods: Two patients using a locked KAFO (LKAFO; one unilateral, one bilateral) and four patients using a stance control orthosis (SCO) for walking were investigated. Tests were conducted with the existing orthosis (baseline) and after a minimum of 7 weeks of C-Brace use. The tests comprised level walking, descending a slope of 10◦ grade, and a stairwell. The measuring technique consisted of two force plates for recording the ground reaction forces (Kistler, sampling rate 1080 Hz) and an optoelectronic 6 camera system for determining kinematic data (Vicon 460, sampling rate 120 Hz). Based on kinematic data and ground reaction forces, the joint moments were calculated [2]. Results: During level walking, the mean time-distanceparameters do not show any significant differences, but 5 of the 6 patients were able to use knee stance flexion (mean knee angle 11◦ ) when using the C-Brace. The mean knee swing flexion angle was 66.6◦ with the C-Brace as compared to 74.0◦ with the SCOs. With the C-Brace, the sound side external joint moments are significantly reduced compared to the LKAFO condition, but do not differ from those with the SCO. With the C-Brace all six patients were able to descend the slope and stairs step over step. Only four patients were able to reciprocally descend the slope, no patient was able to do this on the stairs when using their previous devices. All patients used continuous knee flexion during weight bearing (mean maximum flexion on the slope 65◦ , on the stairs 70◦ ) with the C-Brace. The abnormally high knee extension moments that are unavoidable at ground contact of the sound limb when descending a slope with a SCO/LKAFO were reduced with the C-Brace. Discussion: The present study confirms that the microprocessor hydraulic control of stance and swing phase in the C- Brace supports nearly natural movement patterns on the orthotic side during level walking (use of stance phase flexion, control of swing phase flexion close to the physiological value) as well as controlled knee flexion during weight bearing that offers the patient remarkably increased functional options for walking on slopes and stairs. The nearly natural movement patterns allowed for by the C-Brace suggest that the loads acting on the locomotor system are qualitatively similar to those in healthy individuals. References [1] Zacharias B, Kannenberg A. J Prosth Orthot 2012;24. [2] Bellmann M, et al. Arch Phys Med Rehabil 2010;91:3.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.160 http://dx.doi.org/10.1016/j.gaitpost.2015.06.161
Session OS18 Orthotics The microprocessor controlled C-Brace orthosis and conventional knee–ankle–foot-orthoses: Comparative biomechanical evaluation of functionality T. Schmalz ∗ , E. Pröbsting Ottobock Healthcare, Clinical Research/Biomechanics, Göttingen, Germany Research question: Conventional KAFOs are compared to the C-Brace based on biomechanical parameters measured in ADL situations. Introduction: Patients with pareses or paralysis of the lower limbs often require a knee ankle foot orthosis (KAFO) to restore walking ability. Conventional KAFOs are limited in functionality
Session OS18 Orthotics Optimizing knee kinematics in mid-stance by tuning the ankle foot orthoses-footwear combination of children with cerebral palsy: A case series B. van Beeten 1,∗ , A. Hartman 2 , H. Houdijk 1 1
Rehabilitation Centre Heliomare, Wijk aan Zee, Netherlands 2 Erasmus MC, Rotterdam, Netherlands Research question: Is it necessary and possible to optimize knee kinematics in mid-stance by tuning the ankle foot orthosesfootwear combination of children with cerebral palsy?
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
Introduction: Rigid ankle foot orthoses (AFOs) are commonly used in children with spastic cerebral palsy (CP) to improve gait. The effectiveness of the AFO depends on the type of footwear around the AFO and whether the AFO-footwear combination (AFO-FC) is optimally tuned. Tuning involves making fine adjustments to the alignment of the AFO-FC in order to optimize the kinetics and kinematics of gait [1]. Despite the emerging evidence on the effect of AFO-FC tuning, limited studies exist on the necessity and efficacy of AFO-FC tuning in clinical practice [2]. In this case series we investigated the number of children requiring tuning after provision of an AFO-FC and whether this had a positive effect on their gait pattern. Materials and methods: Ambulatory children with bilateral or unilateral spastic CP aged between 3 and 18 years, who used a rigid AFO or floor reaction orthoses (FRO) to improve walking ability were included in the study. Children with dyskinetic or ataxic CP or who had severe cognitive limitations were excluded. Gait analysis was carried out in a gait analysis laboratory using a 2D video system (BTS, Milan, Italy). Each child walked at their own walking pace on the walkway, barefoot and with their non-tuned AFO-FC. Subsequently, they walked with four predefined alterations to AFOFC alignment: with a 0.5, 1.0, 1.5 cm heel wedge in the shoe or a stiff carbon plate in the shoe underneath the AFO. To explore the necessity and potential to optimize AFO-FC alignment, knee kinematics in mid-stance were assessed and compared in the non-tuned and tuned AFO-FC conditions. A change of >5 degrees knee angle towards the reference knee angle in midstance was considered a clinically relevant improvement. Results: Six boys and four girls mean age 8.5 (sd 4.7) years were included in the study. Eight had bilateral spastic CP and two had unilateral spastic CP. Nine children did not have an optimal knee angle (0–10 degrees knee flexion) in mid-stance during walking with non-tuned AFO-FC. After tuning the AFO-FC with wedges or the carbon plate the knee angle changed >5 degrees towards normal in six of them. In four children knee flexion and in two children knee hyperextension was diminished. Discussion: This study reveals that it is necessary and possible to tune the AFO-FC in children with CP in clinical practice to optimize knee kinematics in mid-stance. Subsequent effects on gait performance needs to be established. References [1] Owen E. MSc thesis. Child Development Centre; 2004. [2] Eddison N, et al. Prosthet Orthot Int 2012;37(2):95–107.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.162
S89
Session OS18 Orthotics The effects of different degrees of ankle foot orthosis stiffness on gait biomechanics and walking energy cost Y. Kerkum ∗ , J. Harlaar, J. van den Noort, J. Becher, A. Buizer, M.-A. Brehm Rehabilitation Medicine, VU University Medical Center, MOVE Research Institute Amsterdam, Amsterdam, Netherlands Research question: To investigate the effects of different degrees of ankle foot orthosis stiffness on knee and ankle parameters and gait efficiency in children with CP. Introduction: Gait of children with cerebral palsy (CP) is often hampered by excessive knee flexion. To counteract the knee flexion, ankle foot orthoses (AFOs) are commonly prescribed. The effect of an AFO on normalizing knee biomechanics may partly be dependent on its stiffness. While stiffer AFOs may normalize knee kine(ma)tics most effectively, very stiff AFOs obstruct ankle range of motion and push-off power, subsequently reducing gait efficiency. A more spring-like AFO may enhance push-off power, but might be less effective in counteracting knee flexion. Yet, a trade- off between normalization of knee kine(ma)tics and enhancing push-off power might optimize gait efficiency [1]. Materials and methods: 15 children with spastic CP (11 boys, 10 ± 2 years, GMFCS level I–III), all walking with excessive knee flexion, were prescribed with a ventral shell AFO with integrated hinge (Neuro Swing® , Fior & Gentz). The hinge was set into three stiffness configurations; rigid (3.8 Nm/deg), stiff (1.6 Nm/deg), and flexible (0.7 Nm/deg). At baseline (shoes-only) and for each AFO stiffness configuration, a 3D-gait analysis and walking energy cost test at comfortable speed were performed. We assessed peak knee extension during single support (KEpk), internal knee flexion moment at timing of KEpk (Mknee), ankle range of motion (RoM), and peak ankle power generation (A2). From the walking energy cost test, the net energy cost (n-EC) was determined. Generalized estimation equations (GEE) were used to analyze the effects of different conditions on all outcome measures. Results: Compared to shoes-only, all AFOs similarly improved KEpk and Mknee. All AFOs reduced ankle RoM, with higher stiffness levels showing less RoM. Peak ankle power generation was preserved with the spring-like AFOs (stiff and flexible), while the rigid AFO reduced push-off power. All AFOs significantly improved n-EC, while speed was not affected by AFOs (see Table 1). Discussion: All AFOs showed comparable improvements in the knee flexion angle and internal knee moment. However, springlike AFOs only showed favorable effects on the ankle RoM and power generation, compared to a rigid AFO. ECnet improvements were comparable for all AFOs. These results suggest that improved peak knee extension angle in stance is more important than enhancing push-off power to achieve walking energy
Table 1 Results of GEE analyses for gait biomechanics, speed and energy cost.
KEpk (deg) Mknee (Nm/kg) RoM (deg) A2 (W/kg) Speed (m/min) n-EC (J/kg/m)
Shoes (N = 15) Mean (SD)
Rigid (N = 14) Mean (SD)
Stiff (N = 15) Mean (SD)
Flexible (N = 14) Mean (SD)
P
Post-hoc
22.7 (8.7) 0.02 (0.18) 35.4 (8.1) 1.49 (0.71) 58.6 (11.3) 6.1 (1.7)
16.7 (10.0) −0.21 (0.23) 7.0 (2.4) 0.73 (0.30) 57.8 (8.0) 5.5 (1.1)
18.1 (8.6) −0.13 (0.18) 15.4 (4.3) 1.21 (0.43) 57.5 (8.4) 5.4 (1.2)
18.4 (9.3) −0.09 (0.18) 19.5 (3.9) 1.43 (0.53) 58.8 (7.4) 5.6 (1.5)
<0.001 <0.001 <0.001 <0.001 0.675 0.008
sh-r/s/f sh-r/s/f; r-f all conditions sh-r/s/f sh-r/s/f