|Year : 2016 | Volume
| Issue : 1 | Page : 22-26
Efficacy of supracondylar knee ankle foot orthosis for hyperextended knee and heel rise in spastic cerebral palsy: A pilot clinical trial
Rajesh Kumar Mohanty, Ullas Chandra Sahoo, Smruti Prava Sahoo
Department of Prosthetics and Orthotics, Swami Vivekanand National Institute of Rehabilitation Training and Research, Cuttack, Odisha, India
|Date of Web Publication||10-Aug-2016|
Rajesh Kumar Mohanty
Swami Vivekanand National Institute of Rehabilitation Training and Research, Olatpur, Bairoi, Cuttack, Orissa
Source of Support: None, Conflict of Interest: None
Background: Guidelines to assist with decision making for orthotic management of gait dysfunction in individual with cerebral palsy (CP) is difficult to derive and remain controversial. The research question is whether supracondylar knee ankle foot orthosis (SKAFO) is one of best options for knee hyperextension and heel rise for spastic diaplegic Cerebral palsy.
Aim: The purpose of this study was to check the efficacy of bilateral molded SKAFO for knee hyperextension and heel rise for Cerebral palsy in terms of gait parameters and energy expenditure.
Materials and Methods: Five individuals (mean age 3.5 years) were diagnosed as spastic diplegic and one with hemiplegic (age 5 years old) Cerebral palsy with delayed milestone presented with knee hyperextension and heel rise during mid-stance and were fitted with bilateral molded SKAFO with pair of shoes. Observational gait analysis by video recording was performed and gait parameters by 10 m walk test and energy expenditure using physiological cost index was recorded in bracing and non-bracing conditions.
Results: The orthosis controlled knee hyperextension by not allowing the knee to go beyond neutral position. The gait was more natural with proper heel strike and better push off. There was improvement in temporal-spatial gait parameters and gait was energy efficient.
Conclusion: The SKAFO was found to be effective in controlling knee hyperextension and resulted in stable, natural, satisfactory and energy efficient gait in spastic Cerebral palsy with knee hyperextension and heel rise. Similar study involving case series can be used to set the prognosis of ambulation and the kind of orthotic interventions needed to optimize the walking ability.
Keywords: Cerebral palsy, hyperextension, orthosis, spastic, supracondylar
|How to cite this article:|
Mohanty RK, Sahoo UC, Sahoo SP. Efficacy of supracondylar knee ankle foot orthosis for hyperextended knee and heel rise in spastic cerebral palsy: A pilot clinical trial. Indian J Cereb Palsy 2016;2:22-6
|How to cite this URL:|
Mohanty RK, Sahoo UC, Sahoo SP. Efficacy of supracondylar knee ankle foot orthosis for hyperextended knee and heel rise in spastic cerebral palsy: A pilot clinical trial. Indian J Cereb Palsy [serial online] 2016 [cited 2017 Oct 19];2:22-6. Available from: http://www.ijcpjournal.org/text.asp?2016/2/1/22/188151
| Introduction|| |
Most children with cerebral palsy (CP) will have spasticity as the main motor disorder and it can be classified either according to which body areas is affected: Hemiplegia, diplegia, tetraplegia, or the movement disorder type: Spastic, athetoid, ataxic, and hypotonic. ,, The muscles of individuals with spastic Cerebral palsy feel stiff and their movements may look stiff and jerky. Gait abnormalities in children with Cerebral palsy are the consequence of contractures across joints, muscle spasticity, and phasically inappropriate muscle action. As described by Becher, 2002  one of the common gait patterns is knee hyperextension and heel rise in mid-stance. Children with spastic type Cerebral palsy commonly walk with ankle equinus.  Making initial contact with the forefoot during walking will usually cause the line of action of the ground reaction force (GRF) to pass well in front of the knee and hip joints, causing an excessive external knee extension moment, perhaps hyperextension (or back-kneeing), and a flexion moment around the hip. Rigid ankle foot orthoses (AFOs) that prevent plantar-flexion and have been appropriately tuned can alter the line of action of the GRF to reduce the resulting abnormal moments around the knee and hip joints, prevent knee hyperextension, and increase hip extension.  The benefits of most orthotic interventions used in physical management regimens for children with Cerebral palsy remain controversial. There continues to be significant variation in the orthotic management of children with Cerebral palsy among treatment centers as a result of conflicting treatment paradigms.  Despite inconclusive literature, , a common conservative treatment is the use of an AFO with an adjustable plantar-flexion stop (APS) that is typically set at neutral or slight dorsiflexion. In addition AFO applications are suggested for mild degrees of genu recurvatum.  These orthoses are intended to prevent excessive ankle plantar-flexion in stance phase, subsequently reducing knee hyperextension. The efficacy of these orthoses and the impact of the angle at which the APS is set, however, have not been studied in an objective manner. Further involuntary movements of lower limb associated in Cerebral palsy with more knee hyperextension is difficult to control by AFO. Supracondylar knee ankle foot orthosis (SKAFO)  is one option for controlling knee hyperextension but none of the studies was found in the literature regarding its efficacy in Cerebral palsy to our knowledge. The purpose of this study was to determine the effect of SKAFO on gait pattern, parameters, and energy expenditure compared to barefoot walking by children with spastic Cerebral palsy.
| Materials and methods|| |
Six individuals out of which five with diplegic (mean age 3.5 years) and one with hemiplegic (age 5 years old) diagnosed as Cerebral palsy were studied on a pilot basis to check the efficacy of SKAFO. All individuals showed delayed developmental milestones. Three individuals were able to walk independently and other three with support. Evaluation of gait revealed knee hyperextension and heel rise during mid-stance. Individuals with no previous history of surgery, free from limitations in the range of movement of the ankle, knee or hip and were able to sit unsupported were selected for our study. An inclusion criteria of Modified Ashworth Scale score two or less and individuals with poor to fair cognitive abilities was set.
Supracondylar knee ankle foot orthosis design
In order to achieve stance phase support and control in all three planes of affected limb, an orthotic design was proposed, fabricated and fitted to check the efficacy. This incorporated characteristic features like preflexed casting of knee of 5-10° whose working principle was based on a couple force system [Figure 1]. Keeping the anterior-superior trim line, just one inch superior to upper edge of patella to achieve sitting cosmesis. Other features include keeping ankle in neutral position, keeping sufficient height of posterior calf, which should also not interfere with sitting knee flexion, supracondylar support, and reinforcement at appropriate areas as per standard prosthetic and orthotic guidelines.
|Figure 1: Different views of supracondylar knee ankle foot orthosis with shoes|
Click here to view
Parameters and instrumentation
Observational gait analysis (OGA) was performed by video recording. Temporal-spatial gait parameters such as step length, stride length, cadence, velocity were compared with and without orthosis by a 10 m walk test  and energy expenditure parameters such as heart rate (HR) and physiological cost index  were studied. A stop watch was used to calculate time parameters and a Heart Rate (HR) monitor was used to measure HR.
In order to assess walking speed in m/s, over a short duration and calculating other gait parameters the individuals were instructed to walk a set distance of 10 m [Figure 2]. Time was measured by a stop watch while the individuals walked the set distance in self-selected walking speed for the intermediate 6 m. The distance covered is divided by the time it took for the individuals to walk the said distance. Collection of three trials was done and the average of the three trials were calculated. The trial was performed for bracing and bare foot conditions. Resting HR before and just after trial was measured by HR monitor.
| Results|| |
The orthosis controlled knee hyperextension by not allowing the knee to go beyond neutral position, i.e., the peak knee extension angle was reduced from 15° - 20° to neutral during mid-stance [Figure 3]. Gait deviations such as excessive lateral trunk bending, involuntary movements were controlled with the use of orthosis as evident from OGA. There was proper initial contact [Figure 4]a resulting in heel to toe gait with SKAFO compared to toe gait in bare foot conditions [Figure 4]b observed in foot prints during 10 m walk test.
The results of temporal-spatial gait parameters are presented in [Table 1], and the results of energy parameters are presented in [Table 2].
| Discussion|| |
The intent of this paper was to study the effects of SKAFO for ambulatory individuals having cerebral palsy walking with knee hyperextension and heel rise by comparing it with bare foot. From the results, it was observed that SKAFO was effective in controlling knee hyperextension and resulted in stable, natural, satisfactory, and energy efficient gait in spastic Cerebral palsy with knee hyperextension and heel rise. This may be due to the fact that control of excessive hyperextension of knee resulted in minimal displacement of center of gravity in either direction, thereby consuming energy. Further, it requires more time for the individuals to bring their limb from hyperextension of knee in mid-stance to flexion required during preswing. This may have resulted in increase in walking velocity, step and stride lengths. Earlier researches have observed that preventing plantar-flexion through the use of orthosis has been found to improve walking efficiency in children with spastic diplegic Cerebral palsy and in other children with Cerebral palsy. , Rosenthal et al. found that the genu recurvatum was well controlled and gait was improved by a fixed-ankle, below-the-knee orthosis for the management of genu recurvatum in spastic Cerebral palsy.  However, it is also important to mention that some of earlier researches found confusing results. Although a variety of AFO configurations have been proven to prevent ankle equinus during the stance and swing phases of gait, their effect on proximal joint kinematics and kinetics, energy expenditure, and functional skill performance remains uncertain.  There is little evidence in the literature showing efficacy of AFOs in children with Cerebral palsy, and the variability in different studies makes it difficult to compare the results. 
Further, tempero-spatial gait parameters for Cerebral palsy individuals by using AFO were found to be conflicting in earlier researches. In a systematic review, Figueiredo et al. found that stride and step length, gait velocity, and single support time did not show any single trend with the use of different designs of AFO. Similarly, the researchers also reported increased double support time with the use of Solid AFO. Cadence decreased with different AFO designs when compared with no AFO. In another two studies, the authors reported no change in cadence with different AFO.  These conflicting results of AFO require a thorough, systematic orthotic design utilizing better lever function and its application in spastic Cerebral palsy.
Considering that knee hyperextension with heel rise in spastic Cerebral palsy is difficult to control, orthotic prescription rationale is based on the degree of deformity, degree of correct ability, potential functional abilities of the patient, and anticipated gait training protocols. Generally, knee orthoses are not indicated  for triplanar and/or severe forms of genu recurvatum as they do not realign the distal base levers or compensate for weakness of the quadriceps or posterior calf group without a locking knee mechanism. Locking the knee joint, which increases metabolic costs, serves to essentially lengthen the limb during swing phase. Further, AFO applications are suggested up to 10-15° of genu recurvatum only. Most studies discussed by earlier researchers were based on solid or hinged AFO but not even a single study was found on SKAFO for Cerebral palsy. Therefore, there was a requirement to study these individuals with an orthosis like molded SKAFO, which immobilize ankle in neutral position and provide full range of knee flexion-extension without locking it, resists genu recurvatum by force couple and provides mediolateral knee stability too. In an attempt to use SKAFO on spastic Cerebral palsy individuals with knee hyperextension and heel rise, we found good results. However, this is a pilot clinical trial including less population, so results cannot be generalized. Similar study involving case series can be used to set the prognosis of ambulation and the kind of orthotic interventions needed to optimize the walking ability.
| Conclusion|| |
The results of our study suggest positive effects of the use of molded SKAFO on gait kinematics as well as on functional activities related to mobility of individuals with spastic Cerebral palsy. The orthosis was found to be successful in controlling knee hyperextension, achieving heel to toe gait, improving temporal-spatial gait parameters, and resulted in energy efficient gait. However, future studies with objective outcomes and modern instrumentation are encouraged to provide valid and applicable evidence to support clinical practice.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]