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Ankle & Foot Splints or Orthoses (AFOs)

Introduction

This information sheet aims to answer your questions about ankle and foot orthoses: what they are, what they do and what the differences are between them. This was written with children in mind, but it is equally relevant to adults, and quotes some adult users on their orthoses.

What are AFOs?

Ankle and Foot Orthoses (AFOs), or splints, are external devices which are used to:

  • Improve or prevent a physical deformity
  • Stabilise a joint or joints
  • Reduce pain
  • Improve mobility or performance
  • Reduce the risk of injury

They have been used for many years to help manage the gait (walking pattern) of children with hemiplegia. They are used to reduce unwanted and uncontrolled movements associated with muscle imbalances, weakness or increased tone (tightness) in the lower leg and the foot and ankle.

Abnormal movement in children with hemiplegia often means a tip-toe walking pattern (equinus or plantarflexed gait) with the added complication of the ankle becoming twisted outwards (varus ankle) or collapsing inwards (valgus ankle).

Posture problems in children with hemiplegia

The adoption of a toe-walking gait also leads to secondary problems:

  • The knee joint tends to snap backwards further than it would normally (hyperextension or back kneeing).
  • Hyperextension of the knee in turn has a harmful effect on hip position, pelvic stability and symmetry. This can affect the child’s balance and general posture.
  • The arm on the affected side will also react as the child fights to maintain his/ her balance when walking.

I am aware that when I walk, my arm comes up. It is almost a balance thing, and it has got worse as my walking got worse, if that makes any sense...It’s not as bad when I have a splint on my leg doing its job properly

Toe-walking gait not only affects the child’s posture, but also increases the potential risk of the development of contractures (shortening) of tendons and muscles, leading to permanent stiffening of the ankle and knee in later life.

How can ankle and foot orthoses help?

One way to help prevent this type of walking is to fit a below-knee ankle/foot orthosis (AFO) which can help control any abnormal movement of the foot and ankle during walking, play or rest.

  • A well-made and close fitting AFO will help stabilise the foot and ankle to bring about ankle stability and improve balance, posture and confidence.
  • Controlling the foot and ankle will also influence hip and knee position in a positive manner and in turn lead to potential improvements in the child’s gait, balance and posture.
  • The foot plate of the AFO can be flat or contoured depending on the child’s requirements. Insoles can be incorporated into the AFO to help maintain a good foot posture.
  • Modifications can also be made to the outside of the AFO or even the child’s footwear after fitting, in order to “fine tune” the AFO. Small postsupply adjustments can also increase the effectiveness of the AFO; this is most commonly carried out to adjust heel height, which changes the angle of the lower leg in relation to the ground when walking (tibial shaft angle).
  • An AFO should be able to fit into the child’s own footwear (not always problem free but usually possible), which means he or she will be more willing to wear it.
  • An AFO should never be uncomfortable for a child to wear and he or she should be able to wear it happily for most of their active day.

Do all children with hemiplegia need an AFO?

Not all children need an AFO. But those who do not have the problems of a toe walking gait may still have general weakness or some instability of the ankle joint complex. This can lead to problems of balance, such as walking with legs wide apart and general loss of confidence.

  • The ankle may tend to collapse into a varus or valgus position.
  • When the back foot is held in a valgus position (collapsing inwards), the arch of the foot tends to flatten along with it (overpronation).
  • Avarus back foot position (twisting outwards) tends to create a high arched foot (supination).

In cases like this, the fitting of foot orthoses can be helpful in reducing unwanted foot and ankle positions and consequently improve balance and posture.

What is dorsiflexion and why is it important?

Ankle dorsiflexion is the movement of the foot at the ankle joint in an upward direction. Hemiplegia can affect a child’s ability to achieve ankle dorsiflexion (resulting in an equinus foot posture), and this impedes walking.

  • Dorsiflexion allows many functions to be achieved easily without overstressing other joints.
  • Without dorsiflexion, gait tends to be jerky and stick-like, as it is difficult for the body and leg to pass over the affected foot and ankle.
  • Without dorsiflexion the energy needed to walk increases.
  • Dorsiflexion also occurs in many other daily activities such as standing from sitting, sitting from standing, crouching, going up and down stairs, walking up hill and walking backwards.

So while the use of a solid ankle AFO can be helpful in certain circumstances (see next section), it is not just incorrect movement that is restricted: all movement of the foot and ankle is lost. Ankle dorsiflexion is a useful function and its loss is undesirable in some children with hemiplegia.

Solid Ankle AFO

AFOs can be made with a solid ankle complex which holds the foot and ankle at 90° to the lower leg (neutral plantargrade position). This prevents the foot and ankle from being pushed down (plantarflexion) and prevents the development of a toewalking gait as well as sideways movements of the ankle (Valgus &Varus movements), but it can hold back the child’s development by not allowing dorsiflexion to occur (see below).

  • Solid AFOs can be used very effectively in providing stability and encouraging a good base of support in young children with hemiplegia.
  • You may find that when a child starts to pull to stand and cruise around furniture a fixed AFO can be a good option to provide support and give confidence to the child.
  • Solid AFOs are also used where an existing contracture (muscle or tendon shortening) already exists and the child may not have any ankle movement present.

Articulated or Hinged AFO

The hinged AFO is in many ways very similar to the fixed ankle type. During the manufacture of the hinged AFO a simple mechanical joint is fitted at the level of the ankle joint and incorporated into the moulding. A backstop is also fitted behind the ankle to prevent plantarflexion (toe walking).

  • A hinged AFO allows dorsiflexion to occur while preventing all plantarflexion past 90 degrees (plantigrade 90o) - the child can bend his or her foot upwards but not downwards.
  • A hinged AFO provides the same medial (inside) and lateral (outside) stability for the ankle as a solid ankle AFO and so prevents valgus or varus positioning.
  • A hinged AFO can provide a more natural, fluent gait, allowing the foot and ankle to dorsiflex during daily activities such as standing from sitting, sitting from standing, crouching, going up and down stairs, walking up hill and walking backwards.
  • However, hinged AFOs are wider at the ankles and this can create more problems when it comes to fitting them into regular footwear.

Footwear and adaptations

The measures which can help reduce ankle and foot instability range from simple supportive footwear, to footwear with adaptations, to complex multi-material biomechanical and functional foot orthoses.

  • Footwear alone has little effect on severe foot instability, but can be useful for improving stability in an unstable ankle when the child starts to walk. The special footwear has a wide, flat, goodgripping sole with increased stiffening around the ankle and this can help give the child a greater sense of balance. But be aware that the foot itself may still roll around inside the boot unseen and therefore careful fitting of this type of footwear is essential.
  • Adaptations to footwear, such as wedges to the inside (medial) or outside (lateral) of the boot, can help increase control over unstable ankles.
  • Foot orthoses can be incorporated into footwear to improve foot stability. These usually come in the form of insoles with arch support and heel cups, which are extended up around the heel but finish below the ankle.
  • Both these types of foot orthoses may have special wedging (posting) fitted, either to the outside (extrinsic) or built into the orthoses (intrinsic) when manufactured. The posting or wedging is fitted to produce a correcting force on the heel when the child is weight-bearing or walking.
  • These foot orthoses are usually constructed of lightweight thermoplastics and made from a cast of the child’s foot held in a corrected position.

I was upset when H was given her first pair of Piedros, she was so dainty and was going to have to wear great big clumpy boots. But she loved them, and we made them pretty with frilly ankle socks. She only took them off for bed, they were her ‘special boots'

I am currently using a specially made insole which has had fantastic results. Before getting it I was told I would have to have an operation as that was the only option left. But since getting it my foot has dramatically improved - my ankle used to roll outwards and my foot would turn in, and now the ankle is completely central…

SMOs and DAFOs

Unlike more traditional rigid orthoses, Supramalleolar orthoses (SMOs - orthoses which finish just above the ankle) or Dynamic Ankle Foot Orthoses (DAFOs - a brand name) are thin and flexible. They come in a variety of designs and can be very useful in improving medial and lateral stability around the ankle.

  • SMOs and DAFOS promote good weight bearing and this in turn can lead to reduced toe walking and also a reduction in muscle tightness.
  • However, they offer little control over increased high tone (muscle tightness), excessive dorsiflexion or plantarflexion. They are therefore not effective for correcting a medium to severe toewalking gait pattern. They do not provide a great deal of control of the foot and ankle during the swing phase of gait or when non-weight bearing.
  • SMOs and DAFOs stabilise the mid and hind foot when the child is standing or when the affected leg is in a weightbearing position during walking (stance phase of gait). This must be taken into consideration when the child is assessed. They are often used when a child is developing skills and their gait is developing so their need for an orthosis gradually decreases.

Lycra orthoses

There are a number of alternative treatments available to the families of children with hemiplegia, which can often be provided via the NHS, or via private health professionals. These include compression garments (lycra orthoses or splints). Although some people use lycra orthoses for their foot/leg, they are more often used for arm/hand. At the moment there is no conclusive medical evidence of the benefits of these garments in children with hemiplegia, but there are families who have told HemiHelp that they have worked for their children. However, they are not the answer for all children with hemiplegia, and care has to be taken, with advice from professionals closely involved in the child’s care as to the efficacy of this treatment.

Design Criteria

Whatever type of orthosis is recommended or fitted, they share many common design points and try to provide some or all of the elements below:

  • Hind foot stability (close moulding around heel).
  • Mid-forefoot stability (medial & lateral extensions, good arch support).
  • Control of unwanted exaggerated and abnormal movements.
  • Reduction of the effects of increased tone (spasticity).
  • Promotion of a stable base.
  • Encouragement of good standing position with equal weight bearing on both feet.
  • Toe and metatarsal support (tone management).
  • Contoured sole plates to assist in foot stabilisation (tone reduction).
  • Construction from semi flexible or rigid materials (polypropylene, polythene etc).

Final remarks

Orthoses are not a stand-alone solution to balance, posture and gait difficulties caused by hemiplegia, and are usually used with other interventions as part of the child’s overall management programme. It is also true that no two children are the same and what works for one might not work for another.

The goal of orthotic management should be to provide the least amount of orthotic hardware possible to encourage and promote the child’s own abilities in achieving a normal gait pattern.

It is important that a full assessment is carried out in a relaxed environment to ensure that the correct orthotic prescription is made. A quick 10-15 minute consultation in a busy clinic to take a decision on orthotic provision and design will most probably not lead to the best outcome. Once fitted with an orthosis, the child needs to have regular reviews to ensure the continued effectiveness of the orthosis as her or he develops and grows.

When a child grows out of his/her orthosis always ask yourself the question: Is my child still getting some benefit from this type of orthosis? Therefore a full assessment must be carried out again to review the type of orthotic management the child needs.

Finally, you can find information on shoes suitable for wearing with an orthosis on HemiHelp’s Shoes sheet. HemiHelp also sells ‘Hands Up for Andie’, a children’s book about a little girl who wears a splint.

HemiHelp is the national charity that provides support and information to families and people affected by hemiplegia, and the professionals who support them.

Helpline: 0345 123 2372 (Mon-Fri 10am-1pm) Office: 0345 120 3713 Email: support@hemihelp.org.uk Website: www.hemihelp.org.uk

HemiHelp makes every effort to ensure the accuracy of information in its publications but cannot be held liable for any actions taken based on this information. We can provide references on the source material we used to write this information product. Please contact us at info@hemihelp.org.uk

© HemiHelp is registered as Charity No. 1085349. Registered office: 6 Market Road, London. N7 9PW. HemiHelp is a company limited by guarantee and registered in England and Wales (Registered No. 4156922). Information on this information sheet may not be reproduced without prior consent from HemiHelp. All rights reserved.

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This information product has been produced following the Information Standard requirements http://www.theinformationstandard.org/

Author: Chris Drake, Senior Orthotic Consultant(2010) Reviewer: Kevin Mann, Senior Orthotist (2014) Last revision 2014 – next revision due 2017

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