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Boltežar, Groleger Sršen Vrečar, Cikajlo, Krajnik, Tomšič, Humar Gorišek / Rehabilitacija - letn. VII, supl. 3 (2008)
DEVELOPMENT OF A NEW ORTHOSIS 
FOR A CHILD WITH CEREBRAL PALSY, 
WITH A KNEE (HYPER) EXTENSION 
IN MIDSTANCE AND INTERNAL 
ROTATION OF LOWER LIMB PATTERN - 
A CASE STUDY
Ž. Boltežar Ž. Boltežar
1
, K. Groleger Sršen
2
, I. Vrečar
2
, I. Cikajlo , I. Cikajlo
2
, J. Krajnik , J. Krajnik
2
, I. Tomšič
2
, M. Humar Gorišek
2
1
 Ortotika in protetika d.o.o., Ljubljana, Slovenia Ortotika in protetika d.o.o., Ljubljana, Slovenia
2
 Institute for Rehabilitation, Ljubljana, Slovenia Institute for Rehabilitation, Ljubljana, Slovenia
of 4.5 years. She walked with pronounced hyperextension 
of knees in midstance and internal rotation of lower limbs. 
Clinical analysis after application of HKAFO showed better 
gait pattern without knee hyperextension in midstance, with 
lesser hip internal rotation and good foot position. She was 
slower, able to stop and to stand for a longer period. Kine-
siology supported clinical findings. We expect a beneficial 
long term effect on gait pattern, but this has to be proved 
through a prospective study on a larger group of subjects.
Abstract 
In conjunction with other interventions for children with 
cerebral palsy (CP), orthoses continue to play an impor-
tant role in the physical management of children with CP . 
A case study was designed to provide a quantitative and 
qualitative analysis of gait pattern of a girl, who is using 
a specially designed twister hip-knee-ankle-foot orthosis 
(HKAFO). She was referred to our Institute at the age 
INTRODUCTION 
Cerebral palsy (CP) is a well-recognized neuro-develop-
mental condition with frequent secondary impairments (1). 
For the function of ambulation, the Gross Motor Function 
Classification System (GMFCS) has been widely employed 
(2). Individuals in levels I an II are able to walk without any 
aid and those in levels III and IV need different types of 
orthoses, walker, crutches…
According to specific gait pattern, children with CP belong 
to one of five groups (3): 
1. insufficient foot lift in swing,
2. knee (hyper)extension in midstance without heel rise,
3. knee (hyper)extension in midstance with heel rise,
4. knee flexion in midstance with heel rise and
5. knee flexion in midstance without heel rise.
In conjunction with other interventions, orthoses continue to 
play an important role in the physical management of chil-
dren with CP. The aims of lower limb orthotic management 
of CP are to correct and/or prevent deformity, to provide a 
base of support, to facilitate training in skills and to improve 
the efficiency of gait (4).
Most frequently orthoses for ankle and foot (AFO) are used. 
There are 4 main types: a UCBL, a leaf-spring AFO, a rigid 
AFO and a floor reaction AFO (5). Quite some studies are 
dealing with the effects of different types of AFO on the gait 
pattern, but there are just a few data on the influence of AFO 
on hip kinematics (6). Children with hyperextension of knee 
in the midstance and internal rotation of lower limb to our 
knowledge seem not to benefit enough from AFO. 
METHODS AND SUBJECTS 
The study was designed to provide a quantitative and 
qualitative analysis of gait pattern of a child with CP, who 
is using a specially designed twister hip-knee-ankle-foot 
orthosis (HKAFO). The orthosis consists of pelvic corset, 
knee orthosis and foot orthosis, connected by an adjustable 
spring. It provides prevention of internal hip rotation, cor-
rection of knee hyperextension in midstance and a good 
foot position. Based on individual analysis, compounds are 
chosen according to intensity of correction that is needed 
in a particular plane. 
A girl was born after uneventful pregnancy 10 days after 
term: weight over 4 kg, height 54 cm, Apgar score unknown. 
She had broken collar bone and was vomiting amniotic 
fluid. Only at the age of one year she was referred to a 
physiotherapist because of a delayed motor development. She 
started to walk at the age of 18 months. Team at the regional 

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health-centre decided to apply inhibitory casting to prevent 
toe-walking at the age of 3 years. After that parents noticed, 
that her gait pattern worsened. She was walking very quickly, 
she was hardly able to stop in was falling frequently. 
She was referred to our Institute at the age of 4.5 years. She 
was able to walk freely, but with difficulties: plantigrade in 
barefoot but compensating with pronounced hyperexten-
sion of both knees in the midstance and internal rotation of 
lower limbs. We decided to apply the twister HKAFO. Her 
gait pattern was analyzed clinically and kinesiologically 
(in the first week after application and again after period 
of 3 months).
RESULTS 
Clinical analysis after application showed better gait pattern 
without knee hyperextension in midstance, with lesser hip 
internal rotation and good foot position. She was slower, 
able to stop and to stand for a longer period.
Kinesiology showed that the gait velocity with orthosis 
was lower (0.25m/s) and cadence was more variable. Gait 
pattern, which was based on moving the center of gravity 
forward and propulsion generation in hips, was changed in 
terms of propulsion generation and securing the stability; the 
hip power generation has decreased and pelvis was adjusted 
toward normal position and consequently moving the center 
of gravity backward. The spring was helpful in the swing 
phase, but not easy to overcome its force. At the same time 
it leaded to less power that was needed for walking. The 
HKAFO application also resulted in smaller pelvic tilt and 
abolished the undesired knee hyperextension. 
Girl and her parents accepted the orthosis very well. Girl 
used the orthosis for several hours per day already in the 
period of adaptation, without any difficulties while com-
mitting to daily life activities. 
DISCUSSION AND CONCLUSION 
Gait patterns of children with CP differ significantly. One 
of possibilities is walking with knee (hyper) extension in 
midstance and with pronounced internal rotation of hip. 
We developed a twister HKAFO to correct this gait pattern. 
Analysis is showing short-term improvement of gait pattern. 
It can be applied through all the day, without any functional 
limitation in performance of daily life activities, which is 
also very important for a child and its family.
There are some questions remaining to be answered. We 
expect that a long term effect will be beneficial, and that 
children will develop a better gait pattern that will persist 
also through a longer period without KHAFO. But this has 
to be proved through larger study within a longer period of 
observation.
R References eferences: 
1.  Bax M et al. Proposed definition and classification of 
cerebral palsy, Developmental Medicine & Child Neurol-
ogy 2005, 47: 571-576. 
2.  Palisano RJ, Hanna S, Rosenbaum PL, Russell DJ, Walter 
SD, Wood EP, Raina PS, Galuppi BE. Validation of a 
model of gross motor function for children with cerebral 
palsy. Phys Ther 2000;80:974-985. 
3.  Gage JR. Gait analysis. An essential tool in the treatment 
of cerebral palsy. Clin Orthop Rel Res 1993;00:126-
134. 
4.  Condie DN, Meadows CB. Conclusions and recommen-
dations. In: Condie DN, Meadows CB, eds. Report of 
a Consensus Conference on the Lower Limb Orthotic 
Management of Cerebral Palsy. Copenhagen: Inter-
national Society of Prosthetics & Orthotics; 1995:15-
19. 
5.  Yates GA. Method for the provision of lightweight or-
thotic orthopedic appliance. Orthopedic Journal 1958; 
1:53-57. 
6.  Lucareli PRG et al. Changes in joint kinematics in 
children with Cerebral palsy while walking with and 
without a floor reaction ankle-foot orthosis. Cllinics 
2007;62(1):63-8. 
Boltežar, Groleger Sršen Vrečar, Cikajlo, Krajnik, Tomšič, Humar Gorišek / Rehabilitacija - letn. VII, supl. 3 (2008)