CLINICAL PROBLEM SOLVING

In this feature details of a real patient are described by the treating clinician and presented instages. The reasons for treatment are also given. A clinician from another country, SheenaIrwin Carruthers from Stellenbosch University, South Africa, has been invited to commenton the treatments and these are given in italic type. Readers are invited to comment on anddiscuss the issues raised in the material presented.

AFOs and KFOs and surgery in cerebral palsy — what to use when?WENDY MURPHY Oxfordshire Community Paediatric Service, Oxford, UK

Key words: cerebral palsy (CP), knee and foot orthoses, surgery.

RJ was born on 1 September 1988, he is now aged 7. He was born by Caesariansection and had a right upper lobectomy at 8 weeks old. His mother states that shewas told that he had cerebral palsy (CP) when he was 9 months old. His lowerlimbs, pelvis and trunk are affected. The right side is more affected than the left.

RJ attended a pre-school nursery from 2 to 3 years of age, a special schoolnursery from 3 to 6 years of age and, to date, is a pupil at a mainstream primaryschool, where he has regular support from a Learning Support Assistant (LSA).

Early treatment and management were conventional, based on the premisethat permanent soft tissue shortening or contracture is a secondary consequenceof constant involuntary muscle action and persistent reflexes and that these areresponsible for abnormal gait.

After persevering with conventional orthotic management for two years, itwas clear that RJ’s gait and function were not progressing.

On examining the literature, it appeared that the long term success of conserva-tive treatment based on this approach has been shown to be limited (Watt et al.,1986; Cosgrove et al., 1994).

An alternative proposal was postulated. It was suggested that shortening was nota manifestation of increased tonic muscle contraction but attributable to continualuse of adaptive motor control strategies. These are adopted by CP individuals inorder to optimise function when stability of posture is impaired (Hare, 1990; Pope,1996). If it is the ‘negative’ features (i.e. weakness) rather than the ‘positive’ (i.e.spasticity) that cause the major performance difficulty (Carr & Shepherd, 1996)then intervention directed towards the reduction of this so-called ‘spasticity’ and/orcontracture is not addressing the primary problem.

A fundamental problem, which appears to be present in all gait pathologies, isthe keeping of postural stability and balance while achieving forward movement

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(Winter, 1994). If stability of posture is a prerequisite to effective function then con-sideration must be given to the biomechanical constraints on the learning of appro-priate strategies in the postural and motor impaired individual (Butler & Major,1992; Mulder, 1996).

A number of studies have been carried out on the effects of the application ofinhibitory casts and ankle–foot orthoses (AFOs) in children with CP (Butler, 1991;Ricks & Eilert, 1993). However, a search of the literature revealed little on theeffects of knee and foot orthoses (KFOs).

RJ was first seen in October 1991. Before embarking on treatment, a physicalassessment was carried out. When seen in sitting, his pelvis was tilted posterio-rally. His spine presented with a long postural kyphosis, a developing ‘chin poke’and a postural scoliosis, concave to the left. His hips were in neutralabduction/adduction and internal/external rotation. Both feet were plantigrade.

RJ could stand, supported by a rollator. The position in which his spine washeld reflected that in sitting, though less kyphotic. He exhibited a typical(crouch) posture, i.e. adducted, inwardly rotated, and flexed at the hips, flexed atthe knees and feet everted with minimal longitudinal arch. Problems were moresevere on the right side. Whilst standing and holding on to a secure support, i.e. atable or rollator, RJ could, with concentration, correct his posture to stand withhips in neutral, with knees extended and feet plantigrade.

When walking, holding a rollator for support, he stepped through with eitherleg with even strides. He had a heel strike with the left foot and a flat foot strikewith the right. It was apparent that his right leg was less reliable than his left intaking his body weight All the postural problems described were exacerbatedwhen he stepped on to the right leg.

SIC No details of this child’s early development are given but if he was diagnosed at only9 months of age it is likely his impairment was not severe. From the description hewould seem to fit the picture of a spastic diplegic. The problems are stated in terms ofhis posture in sitting, standing, and walking. If problem analysis is to be useful indetermining the treatment plan it should include detailed and accurate analysis of theunderlying factors responsible for the patterns of posture and movement seen. In thiscase the lengths of three muscle groups (adductors, hamstrings and triceps surae)have been expressed in terms of range of movement and restrictions noted do notappear sufficient to account for the standing and walking patterns noted. We do nothave any indication of the range of hip extension, where lesser restriction can con-tribute to the problems described, particularly if gluteus maximus is inefficient in per-forming its function of extension and lateral rotation of the hip. Abnormalities ofbiomechanical alignment may be a causative factor in the development of a ‘crouch’gait, or may develop secondary to other underlying causes, such as increased ordecreased postural tone, muscular imbalance, persistent positioning or behaviouralstrategies (habit patterns). Of particular importance is the alignment of the pelvic hipcomplex and alignment of the foot during the weightbearing phases of walking.

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On examination, the range of movement in RJ’s hips and ankles were slightlyreduced, with the right side more affected:

• Right/ left abduction in extension 25/30˚.• Right/left straight leg raise 30/40˚.• Right/left dorsiflexion 90/100˚.

A positive Thomas’s test indicated the presence of hip flexor tightness. Contrac-tures were not severe at this stage and were not signifant in the context of RJ’s motorperformance.

His problems were defined as follows: in standing, he exhibited a ‘crouch’ stance;his feet rolled into valgus on weightbearing; he needed to lean heavily on a rollatoror plinth for support which precluded him from using his hands for function. Hisproblems were exacerbated when he increased the load through his right side bystepping on to his weak right leg.

Physiotherapy treatment was aimed at maintaining soft tissue length; facilitatingRJ’s posture in sitting, standing and walking; and developing his gross and fine motorskills.

To stabilise joints of the limbs, RJ spent 2–3 hours, during the school day, in longleg gaiters (wrap-around, tubular supports, used as a therapeutic aid).

By the use of gaiters for work in standing and stepping to stabilise his legs, RJ wasbetter able to mobilise his pelvis selectively, equalise his weightbearing, reduceinward rotation and adduction of his hips, take more even and longer steps and keephis feet plantigrade. He did not exhibit a ‘crouch’ gait.

RJ did, of course, walk with a stiff-legged gait, but was happy to do so andappeared to be as mobile in gaiters as walking free. At this stage he was using a rolla-tor for support.

RJ saw an orthopaedic surgeon in January 1992, and his limited range of dorsi-flexion was discussed. This was then 90˚ right, 100˚ left, indicating shortening of softtissues (soleus, gastrocnemius, Achilles tendon).

It was decided to apply bilateral Plaster of Paris walking boots (POPs). Plastercasts in the conservative treatment of CP have been used for a number of years.Below-knee casts were applied to inhibit abnormal patterns of motor activity and tofacilitate more appropriate patterns of muscle function. (Bobath & Bobath, 1964;Sussman, 1983; Watt et al., 1986).

In February 1992, following the removal of the POPs, three-point pressureAFOs were applied. AFOs are used, in the treatment of CP, aiming to produce amore normal gait pattern by positioning peripheral joints in a way that reducespathological reflex patterns and/or by blocking pathological movement of the joint(Middleton et al., 1988).

RJ found them difficult to tolerate. The following observations were made: hewas toe walking with knees flexed ++; his walking pattern was worse; and his func-tion compromised. After five weeks, the AFOs were substituted by Piedro boots,which allowed movement of the feet and ankles within them. RJ’s walking pattern

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in the boots was described as no toe walking, knees more extended. POP boots andAFOs were tried in various combinations a further five times, from early 1992 untilDecember 1994, without success.

It became apparent that when RJ’s feet and ankles were stabilised (by AFOs) hisgait and function deteriorated. Every time they were applied he became moreflexed, adducted and inwardly rotated at his hips, flexed at his knees and he toewalked. However, when his knees were stabilised (by gaiters) his gait and functionimproved. He walked with a stiff-legged gait with an increased base of support,which appeared to be less tiring for him and freed his hands for function.

SIC Provided physiotherapy also addressed pelvic mobility, the achievment of a neutralpelvic tilt and hip extension in standing, the use of gaiter splints during standing andweight transference is often useful. Their use during walking requires careful evalua-tion as the restriction of the swing phase may, in turn, give rise to secondary prob-lems. Inability to release the knee at toe off appears in this case to have given rise toa wide-based gait which would prevent both adequate hip extension and efficientweight transfer during walking. Both POP boots and AFOs can be used for two rea-sons: firstly, to inhibit spasticity and /or apply stretch to overactive or shortened mus-cles; secondly, to achieve optimal alignment in weightbearing. In my experience theresults are most successful when used to achieve optimal alignment, and this is also aprerequisite for any success in using POP or AFOs to achieve inhibition, sincenormal alignment is mandatory for appropriate patterns of muscle function. It is pos-sible that the degree of stretch provided by the POP/AFO was only achieved at theexpense of alignment, and that the deterioration in the walking pattern resulted fromthis. Another possibility is that the increased degree of dorsiflexion provided by thesplinting led to an increase in the flexor patterns throughout the lower limbs, thusreducing the child’s inability to maintain hip and knee extension.

From October 1991 to January 1993, RJ’s ranges of movement, general bodyposture and gross motor function remained constant.

By January 1993, RJ was able to walk independently and no longer relied onthe support of a rollator. Work in gaiters continued, but being fully independentlymobile, he was less tolerant of them in school and refused to wear them at all athome. (Gaiters are not very practical for use with fully mobile children becausethey do not allow knee flexion and therefore have to be repeatedly doffed anddonned, to allow the child to sit down). Without help to balance (from a walkingaid), the adaptive strategies that RJ needed to use to remain upright were exacer-bated. A gradual deterioration of the ranges of movement, in particular the rightAchilles tendon, and general body posture, was observed, dating from the timewhen he started to walk without support.

By December 1994 the range of right ankle dorsiflexion was reduced to 70˚and function was severely impaired because RJ did not have an efficient surfacethrough which to bear weight. The right AFO, applied in December 1994, wasmade to accommodate the shortened Achilles tendon but he was unable to tolerate

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it. Gait was not improved, although RJ walked more slowly in the AFO and aknee extension movement was observed.

RJ saw an orthopaedic surgeon in January 1995. No therapist was present at theappointment. The following surgical procedures were proposed: release of the leftand right adductors, hamstrings and Achilles tendons and a derotational osteotomyof the right femur.

A 10-minute video recording was made in February 1995, in the gait analysis lab-oratory, of RJ’s motor performance in kneeling, high kneeling, walking with barefeet, and walking in shoes and right side AFO.

It is important to note that RJ was able to ‘kneel walk’, an activity in a positionwhere the centre of gravity is relatively low, with a wide base and abducted hips sug-gesting that the adductors were not significantly tight and with no observableincrease in hip flexion.

SIC The comment that at the age of nearly 6 1/2 years, this child was able to kneel walkwith a wide base and abducted hips is interesting and supports the contention that bothpoor foot alignment in weightbearing and lack of postural control in weightbearingcontributed to the difficulties in walking upright. The latter supposition is supported bythe observation that kneel walking was achieved with abducted hips; in other words,increased knee flexion led to increased hip abduction (part of the flexor synergy).

It appeared that with the increase in height from kneeling to standing, RJ’s bal-ance was more threatened, and that his adducted, ‘crouch’ stance when walkingcould be attributed to the adaptive strategies needed to remain upright, because ofhis generalised weakness.

The strategies used by RJ to remain upright — locking his weaker right leg intohis stronger left leg by adducting, internally rotating and flexing at the hip and atthe knee — made it impossible for him to put his heel to the ground and, therefore,appeared to be a major reason for the contraction of the Achilles tendon. RJ’s prob-lems were identified as:

• Unstable right leg and foot for reliable, safe weight transference.• Both arms and right leg appear to be used to assist postural stability in

walking.• Action of right leg and foot in walking predisposes to tight Achilles tendon.

Following discussion, the orthopaedic surgeon agreed to limit surgery to thelengthening of the right Achilles tendon. The objective was to create a plantigraderight foot to provide a reliable safe supporting surface.

It was decided to help RJ to balance by use of a KFO on the weaker right leg toalign and stabilise his ankle and knee, thus giving him a wider base of support tofacilitate a more stable posture and aim to reduce the need for the coping strategiesdescribed above, improving his overall balance, stability and function.

From May until July 1995, to prepare RJ for the prospect of wearing a KFO post-operatively, he wore a full-length gaiter on the right leg for all standing and walking,

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at school and home. His mother, the Learning Support Assistant and class teacher inschool understood the aims and intentions and were reliable in doffing and donningthe gaitors for him.

On 13 July 1995 the orthopaedic surgeon performed a percutaneous lengtheningof the right Achilles tendon and a full-length POP was applied. After three weeksthe POP was removed and a cast was taken by the orthotist, from which to makethe right KFO and left AFO. The POP was re-applied for a further three weeks.

On removal of the POP, it was apparent that an excellent plantigrade position ofthe right foot had been achieved by the lengthening of the Achilles tendon. Thesplints were applied immediately and RJ could walk in them straightaway, taking oneweek to develop independent balance.

RJ wears the KAFO and AFO from rising until supper time, seven days a week,with a two-hour break in the middle of the day, during which he rides his tricycleand plays football.

In school term time his LSA works with him for 30 minutes a day, on physical activi-ties designed to facilitate functional states of balance (the centre of mass over the base ofsupport) when maintaining a position, when making postural adjustments to voluntarymovement, and when reacting to outside perturbation of posture (Berg, 1989). Duringthese sessions he works in his KFO and AFO for 15 minutes, relying on the KFO for sta-bility, enabling him to move his body weight over the supportive splint with confidence.The activities are then repeated without splints or shoes, aiming to capitalise on theappropriate stimulation of the postural mechanisms which have just occurred.

A split-screen video recording was made in October 1995, in the gait analysislaboratory, of RJ standing and walking in bare feet, and standing and walking wear-ing the KFO and AFO. Observation revealed that, when wearing the splints, hewalked independently and confidently with an improved base of support. He hadbilateral heel strike and a knee extension moment on the left. He was able to turnthrough 180˚ to the left or right.

In July 1996, RJ continues to follow his routine of postural management asdescribed. He likes to wear his splints, saying that they make him feel safe.

SIC The decision to limit surgery to lengthening of the right Achilles tendon was a wiseone. In view of the tendency towards a mass flexor pattern when any increase wasbrought about in a flexor component, post-operative management in an above-kneePOP and later a KFO could also be justified. It appears that current treatment isfocused upon postural control in standing. At this stage it would be advisable to per-form a full evaluation and analysis of his problems in standing and walking, withouthis splints in order to determine the underlying causes of these problems and plan atreatment programme aimed at enabling him to discard the KFO in the not too dis-tant future. In particular, mobility and control of the pelvis and hip joint need carefulevaluation. Routine hip X-rays are also indicated in rotation. In addition, sinceproblems of foot alignment disguised by the splints and can lead to deterioration inactive control which may be noted when he is wearing the KFO, it might be advis-able to take X-rays of the feet during weightbearing in splints.

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The ranges of movement in RJ’s hips, knees and ankles are less than normal.However, no soft tissue is contracted to the point where his functional ability is significantly affected, and the range of movement remains constant.

Dorsiflexion of the right Achilles tendon, pre-operatively reduced to 70˚, retainsits post-operative range of 110˚.

RJ has responded well to the application of a KFO to his right leg. Soft tissuesknown to be vulnerable to contracture have retained their length; the right Achillestendon which was severely contracted, and released surgically, has retained itslength; he walks more efficiently, in terms of reduction of fatigue; major surgery wasavoided and to date is not necessary.

SIC This is an interesting case hisory which demonstrates the need for full evaluation andproblem analysis in order to identify the underlying factors responsible for the abnor-malities of posture and movement noted. Orthopaedic intervention by means ofsplinting and surgery is often indicated, but such intervention does not replace anaccurate neurodevelopmental and biomechanical assessment. By pinpionting under-lying factors it becomes possible to delineate specific objectives and plan treatmentprogrammes accordingly.

ACKNOWLEDGEMENT

The author would like to thank her colleagues, Pauline Pope and Sally Rossiter, for their help andencouragement in preparing this paper.

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Address correspondence to Wendy Murphy, ‘Westleigh’, West End, Chipping Norton, Oxon OX7 5EX, UK.

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