An orthosis is defined as a device attached or applied to the external surface of the body to improve function, restrict or enforce motion, or support a body segment(bradom). Orthosis derives from the Greek expression “making straight”. An orthosis is an orthopedic appliance used to support, align, prevent, or correct deformities of a body part or to improve the function of moveable part of the body. Orthesis is sometimes used to denote an orthosis; brace is synonymous with orthosis. A splint is a temporary orthosis. Some of the other common terms that denote particular orthotic design include sling, corset, pressure garment, and cuff. Surgical appliance is board category that includes orthoses. Orthotic is the adjective relating to orthoses, but it is sometimes used to designate a foot orthosis.
Othoses should be used for the specific management of selected disorders. As in all fields of medicine, specific treatment should be based on specific medical diagnosis with an established goal of treatment. Placement of orthotic joints should approximate anatomic joint. Most orthoses utilize a three-point system to ensure proper positioning of the limb within the orthosis.bradom
Orthoses are designed with one of two primary aims: either to affect the body structure or to assist function, although for children with CP, orthoses are frequently designed to achieve both of these aims. The aims of lower limb orthotic management of CP were identified by the consensus conference convened by the International Society of Prosthetics and Orthotics6: to correct and/or prevent deformity, to provide a base of support, to facilitate training in skills, to improve the efficiency of gait.
It is clear that the first of these aims fits with interventions designed to affect the body structure, whereas the remainder involve overcoming activity limitations. These aims may similarly be applied to the role that orthotic interventions can play in the management of postural impairments of the trunk and upper limbs. However, some degree of compromise is necessary because orthoses prescribed to prevent or correct deformities can impose additional activity limitations by restricting movement.
To Correct and/or Prevent Deformity
Mobile joint deformities caused by gravity or unbalanced muscle forces can be corrected passively and the position maintained using orthoses. Fixed deformities caused by relative shortening of muscles and soft tissues and structural deformities of abnormal bone shape cannot be passively corrected and must be accommodated in orthoses. Ensuring that muscles spend more than 6 hours during each 24-hour period in an elongated position may help to prevent or reduce the rate of progressive contractures.7 However, stretching muscles using active forces for shorter periods may perhaps be more effective than maintaining a static position to increase muscle length and hence the available range of motion at joints.8
To Provide a Base of Support
Stability in any position of lying, sitting, or standing requires consideration of both intrinsic and extrinsic factors. Intrinsic stability involves controlling the position of the center of mass within the body. Extrinsic stability involves maintaining the center of mass within the supporting area. Hip abduction orthoses may improve stability and sitting balance by increasing the size of the support area, either in combination with a spinal orthosis or by encouraging independent control for the position of the center of mass of the trunk. Similarly, standing frames use hip-knee-ankle-foot-orthoses to control body position and wide bases of support to provide upright postural stability. To Facilitate Training in Skills Normal functional development can be impeded by impairments of coordination and movement. Orthoses can maintain optimum biomechanical alignment of body segments encased within the orthosis. These effects may enable children to overcome activity limitations by focusing training on unrestricted parts of their bodies over which they have better control. Common training targets include encouraging head control by providing trunk stability or using wrist orthoses to facilitate manual dexterity when grasping objects. For lower limb orthoses, the effects also include influencing external movements acting around proximal joints by altering the line of action of the ground reaction force during standing and walking.9 There may be some motor learning effect when children repeat movements through the altered sensations provided by the orthosis.
TO IMPROVE THE EFFICIENCY OF GAIT
Children who are able to achieve upright locomotion must be encouraged to optimize their ability to achieve an efficient gait. Gage11 has described the prerequisites of normal gait:
stability of the supporting leg during stance phase: requiring an appropriate foot-floor contact area, minimizing the external moments acting on the knee, and creating adequate hip abduction power to prevent the pelvis dropping on the unsupported side.
Clearance of the foot from the ground during swing phase: requiring adequate hip and knee flexion and ankle dorsiflexion of the swinging limb. Appropriate prepositioning of the limb at the end of swing phase: created by knee extension and ankle dorsiflexion. Achieving an adequate step length: by hip extension of the stance limb and unrestricted advancement of the swinging limb. Conservation of energy expenditure through reduced excursion of the center of mass of the body.
Lower limb orthoses may improve gait efficiency by restoring these prerequisites through the manipulation of forces acting on the body. Orthoses may reduce energy expenditure further by decreasing the need for compensatory gait deviations to achieve locomotion.
A thorough assessment of the child’s needs is essential. The needs of each child will be influenced by the severity of their impairment and their individual activity limitations. The consensus conference document considered orthotic intervention as relating to three levels of function (i) the prestanding child (recognizing that this may be the highest level of activity for some children), (ii) the standing child, and (iii) the walking child.6
Collating the information required to define the treatment goals and therefore decide whether an orthosis will form a useful part of an overall physical management plan is a multidisciplinary task. The information required will usually include a precise diagnosis using the SCPE classification; functional gross motor status using the GMFCS; measurement of ranges of joint motion both passively and actively; selective muscle control, strength, and spasticity; and joint congruency and integrity judged by radiological investigation. In addition, an assessment of sitting and standing balance and gait analysis will be required for children with those abilities. Other factors influencing the development of a realistic plan for physical management include considering the environments in which the child interacts, behavioral characteristics, and any relevant associated conditions, such as epilepsy, gastroesophageal reflux, or the need for gastrostomy feeding tube access.
Once the treatment goals are defined, many therapeutic interventions other than orthoses are available, such as oral, intramuscular, or intrathecally administered medications, orthopaedic and neurological surgery, physical and occupational therapy, wheelchairs, walking aids and other assistive technology, and temporary splinting and casting. These interventions may be prescribed either as more efficacious and appropriate in achieving the treatment goals or to supplement and reduce the demands required of an orthosis. However, children with CP are frequently prescribed orthoses. A follow-up study of a population of children between 5 and 16 years old demonstrated that half the children were prescribed some orthosis in a 9-month period.12 This study is likely to have underestimated orthotic prescription, because the study period was shorter than the average time (10 months) in which some children outgrow their orthoses.
Whatever the treatment goals and design of orthosis selected, a family-centered approach will encourage appropriate use of an orthosis within the prescribed treatment regimen. The health care team, including the orthotist, must therefore be well coordinated, work in partnership with the family, provide adequate general and specific information about the condition and the role of the prescribed orthosis, and support the family to ensure the orthosis is used correctly.
Following the earlier recommendation to distinguish the needs of the prestanding, standing, and walking child, this review will also attempt to describe the appropriate orthotic management of children with CP with reference to the GMFCS.
GMFCS Level V, Level IV up to Age 6 Years, and Level III Before Age 2 Years
Prestanding children will spend all their time in either lying or sitting postures. Based on earlier work to develop systematic assessment protocols,15 the Chailey scales of ‘levels of ability’ in lying, sitting, and standing provide another framework for assessing the progress of children with postural impairments.16 Achieving the sequence of postural tasks set out in the Chailey scales requires the child to accomplish discrete improvements in motor development and mastery of balance and coordination. The acquisition of skills or alternatively the provision of postural management aids, which enable independent lying, sitting, and standing, can free the senses and upper limbs from stabilizing the body, promoting activities of dexterity and oromuscular function, thereby facilitating cognitive and social development. Although lying supports and seating systems are in principle orthoses because they apply forces to the body to compensate for the impairment, they are beyond the scope of this article because they are forms of assistive technology not usually supplied through the orthotic clinic. The children considered in this section are the most severely limited and will usually have bilateral involvement and spastic type CP.
PROBLEMS OF CEREBRAL PALSY ON TRUNK
As stated earlier, children with CP who are more limited in their activities are at greater risk of contractures and therefore deformities. Children with lower levels of ambulation, corresponding to children classified with GMFCS levels IV and V, are at greater risk of scoliosis.17 Scoliosis also seems to be aggravated by the effects of gravity when affected persons are artificially placed in the sitting position. Rigid plastic thoraco lumbar sacral orthoses (TLSOs) may reduce spinal curvature and improve sitting ability while the orthosis is worn however, TLSOs are unlikely to alter the rate of progressive deformity.19 For children with large structural scoliosis, surgical stabilization may be the more realistic intervention to offer.
When casting for spinal orthoses (TLSOs), it is desirable to remove the deforming axial effects of gravity. Because the treatment goal is to enable a comfortable and functional sitting posture, overcorrection may not be indicated. Tight hamstrings, as demonstrated by a reduced popliteal angle, can reduce the lumbar lordosis by posteriorly tilting the pelvis (sometimes called sacral sitting). Children with poor levels of sitting ability may also demonstrate excessive forward trunk leaning or thoracic kyphosis. Spinal orthoses may prevent forward leaning, and one study has suggested that the improved positioning achieved with a spinal orthosis may in fact improve pulmonary functioning.
MILLER The preferred orthotic is a soft thoracolumbar sacral orthosis (TLSO) with metal or plastic stays that are embedded in a soft plastic material (Figure 1.). This soft material is well tolerated by sensitive skin and does not apply high areas of pressure. This soft TLSO works like a corset to support sitting. The orthotic may be worn over thin clothing so it is easy to apply and remove by caretakers. The TLSO is worn only at times when caretakers feel that the children have direct functional benefits. These orthotics are never worn during sleeping hours. Breathing may be restricted if the orthotic is too tight; however, the gain from upright sitting is approximately the same as the restriction from the orthotic.
For children with gastrostomy tube feedings, an abdominal cutout is required, which provides sufficient space and does not cause irritation. The indication for a soft TLSO is determined by the families’ and caretakers’ goals, with many families finding the adaptive seating working very well and thus no orthotic is needed. For families with children who sit in many different seats, the soft TLSO is especially helpful. The soft TLSO is made from a mold produced from a cast of the child’s body. No attempt is made to get specific scoliosis correction, only to provide trunk alignment that maximizes children’s sitting ability.
Usually, kyphosis is the result of truncal hypotonia and poor motor control. This deformity may slowly become fixed in some children; however, for most, it slowly resolves during adolescent growth. The initial treatment of kyphosis is by wheelchair adjustment and the use of a shoulder harness or anterior trunk restraint. However, there are children who do not tolerate the strong anterior trunk restraints or shoulder harnesses. Orthotic control of kyphosis requires the use of a high-temperature custom-molded bivalve TLSO (Figure 2.). This orthosis must extend anteriorly to the sternal clavicular joint and inferiorly to the antero superior iliac spine. An abdominal cutout may be used if needed for a gastrostomy tube, but this should not be used routinely. The posterior shell needs to extend proximally only to the apex of the kyphosis. This orthotic provides three points of pressure to correct the deformity. Because kyphosis requires a very high force to correct the deformity, the orthotic will deform if it is not very strong. For this reason, the soft material construction of the scoliosis TLSO does not work for kyphosis. There are no data to suggest that the kyphotic-reducing bivalve TLSO has any impact on the progression of the kyphotic deformity; therefore, the orthotic is prescribed only for the functional benefit of allowing children to have better upright sitting posture and better head control. This orthotic should be used by children during periods of sitting when it is providing a specific functional benefit. The bivalve TLSO is never worn during sleep times. This bivalve orthosis is also constructed over a custom mold made from a cast of the child.
|Figure 1. This orthotic is made with a soft plastic in which stiffer plastic stays are embedded to provide better support. The orthosis is only worn when it provides functional benefit, such as during sitting activities, and is never worn at night. If the child has a gastrostomy tube, the orthotic can be cut out to accommodate the tube.Figure 2. To control a kyphotic deformity, much stronger anterior support is required. The anterior aspect also needs to be high to the level of the sternal notch and low to the pubis; this requires a bivalve design in which there is an external shell of high-temperature plastic lined inside with a softer plastic.
Often, low back pain is the presenting symptom of acute spondylolysis and mild spondylolisthesis. If the pain is protracted, or the spondylolisthesis is acute, the pain should be treated for 3 to 6 months with a flexion lumbosacral orthosis (LSO)(figure 3). This lumbar flexion orthosis is usually made from a low-temperature plastic that wraps around the lumbar
|Figure 3 For children who develop low back pain, usually from acute spondylolysis, a lumbar flexion jacket is required. This orthotic is higher in the back to prevent lumbar extension or lordosis and is low in the front and usually front opening. Many types of this orthotic are commercially available; however, many children need to be custom molded because the appropriate fit cannot be obtained from the available models.|
spine and abdomen, maintaining the lumbar spine in flexion. The lumbar flexion orthosis may be molded directly on a child, or made from a mold produced from a cast. There are some commercially available lumbar flexion orthoses; however, they usually do not fit children well, especially children with CP whose body dimensions do not fit typical age-matched peers. This lumbar flexion orthotic should be worn full time for 2 to 3 months except during bathing. After this, the orthotic is worn only during the day for an additional 2 to 3 months, and then children are gradually weaned from the brace. Back pain should diminish very quickly after the initiation of the orthotic. Usually, within 1 week of full-time orthotic wear, children will report a significant reduction in their level of back pain. The spondylolysis may not heal during the brace wear and often remains; however, the pain almost always disappears and does not return.
PROBLEMS OF CEREBRAL PALSY ON HIP
The incidence of hip subluxation and dislocation is also associated with greater activity limitations. Hip dislocation requiring treatment before age 5 years was observed more commonly in children with bilateral spastic CP who were nonambulant compared with those who could walk 10 steps by age 30 months22 (that perhaps excludes children in GMFCS Levels III to I). Orthoses can be used to abduct and flex the hip joint to increase containment of the femoral head in the acetabulum and stretch hip adductor muscles. Abducting the hips to increase the size of the base of support and anterior tilting of the pelvis, so that the center of gravity of the upper body falls within the support area, also greatly improves sitting stability. For non ambulant children, the benefits of the TLSO in controlling the position of the center of gravity and stabilizing the trunk as a single segment can be combined with hip abduction orthosis providing a stable base. Hip abduction spinal orthoses (HASOs) may be used in conjunction with wheelchair seating systems or as alternatives to the wheelchair, allowing the child to sit in regular furniture. The HASO consists of a bivalved, custom-made plastic thoracic-lumbar-sacral orthosis, closely molded around the waist and pelvis, connected to thigh cuffs with an orthotic hip joint that can be locked at 90° of hip flexion23 (Figure 4 ). In this orthosis, maximum external control of sitting posture is provided. Because the same hip joint can also be locked with the hip extended straight, the HASO can be useful for all the activities of lying, sitting, and standing.24,25 It is also worth noting that although these HASOs will preferably hold the child in a symmetrical posture, hip adduction deformities must be accommodated.
|Figure 4. Hip abduction spinal orthoses(HASOs) consist of a bivalved, tom-made plastic thoracic-lumbar-sacral orthosis to stabilize the trunk as a single segment combined with hip abduction to provide a|
|Figure 5. An orthotic joint that allows incrementa adjustment of hip flexion and abduction can be incorporated into an orthosis as an alternative to a hip spica cast after hip reconstruction surgery.|
Therefore, it may be necessary to provide an asymmetrical hip position to maintain neutral pelvic posture. In some seating systems, knee blocks are additionally used to apply an axial force along the femur to the hip in a further effort to prevent pelvic rotation.22 Despite the efficacy of the HASO as a sitting orthosis, there is not yet evidence that it can alter the natural history of progressive hip migration and subluxation. Surgery may be necessary if painful subluxation is limiting activities. A similar metal and leather design can be fabricated using the same orthotic hip joint.26 However, the efficacy of the conventional nonmolded design is undermined by its limited control of the pelvis and multisegmental trunk and will usually require a separate spinal orthosis.
The use of a hip abduction orthosis is often discussed in conferences; however, there are few objective data to support this use. The use of a hip abduction orthosis before surgical lengthening of the adductor muscles causes more harm than benefit based on modeling studies and objective reports. Therefore, abduction bracing of the hip should not be used to prevent hip dislocation before hip muscle lengthening surgery. Abduction bracing after muscle lengthening may improve the recovery of the hip subluxation; however, it may also increase the risk of severe abduction contractures. Therefore, in the balance, abduction bracing has little use after muscle lengthening. There is no objective evidence that abduction bracing is functionally beneficial to control scissoring gait in children with poor motor control. Rather than using large hip abduction orthoses, a much simpler and easier method to control scissoring gait is to use strings from the shoes attached to rails along the lateral sides of the walker. These strings will laterally restrain the feet so they do not cross the midline.
Internal rotation of the hip is very common in children with CP. There has been a long history of using twister cables or similar devices that are attached to waistbands proximally and to the feet distally, often via an AFO. These externally rotating devices have no published documentation of providing any functional benefit to children, or of aiding the resolution of the internally rotated gait either in the short term or in the long term. These externally rotating devices often slow children because they increase stiffness in the extremities. In this way, the use of these devices is somewhat similar to adding increased muscle tone or spasticity, of which these children usually have too much already. Also, the externally rotating stress tends to be concentrated at the knee joint, which is the joint with the least muscle force available to resist the torsional stress that the orthotic applies. This external rotation force can potentially cause damaging stretching of the knee ligaments. Because there is no functional benefit and significant potential for harm, the use of rigid strong twister cables to counter internal rotation of the lower extremities should be abandoned.
The use of elastic wraps has also been advocated to help control hip internal rotation. Usually, these wraps are attached to the proximal end of an AFO, wrapped around the thigh, and attached to a waistband proximally. These bands add relatively little force and almost no weight. Therefore, the negative effects of the twister cables are eliminated, and there are occasional children who seem to gain some minimal benefit from the use of these bands. These twister bands cause little harm and are reasonable to try in children who do not have strong spasticity or high fixed femoral anteversion but are mainly having internal rotation deformity of the hips secondary to poor motor control.
Knee orthotics have a very limited use. Rarely, in children with back-kneeing that is causing knee pain or a worsening deformity, the only option may be limiting knee extension with a knee-ankle-foot orthosis (KAFO) using a free knee hinge that prevents hyperextension. Also, children with severe knee flexion contractures who have undergone posterior knee capsulotomies need to have prolonged postoperative bracing to prevent the recurrence of the flexion contractures. The best orthotic to use is a KAFO with a step-lock or dial-lock knee hinge so the knee can be gradually extended further as tolerated by the child . These orthoses cannot be used immediately postoperatively until the acute swelling subsides. For the first month, bivalve casts are usually used until children can tolerate the orthotic. The KAFO should be used for 12 to 16 hours per day after posterior knee capsulotomies, with the goal of having children sleep in the orthotic with their knee fully extended. After 6 months in the KAFO, and when their knee extension has remained stable, the orthotic can be slowly weaned and then discontinued sometime between 6 and 12 months postoperatively. The most common knee orthosis is the knee immobilizer, which is usually constructed of foam material in which plastic or metal stays are embedded. The orthosis is wrapped around the limb and held closed with Velcro straps (Figure7). The knee immobilizer is used as a knee extension orthotic after hamstring lengthening or for nighttime splinting for hamstring contracture
|Figure 6. There are a few children with severe knee flexion contractures, especially those in whom surgical release is planned, who need progressive strong extension stretch. For these, a custom molded knee-ankle-foot orthosis (KAFO) with soft plastic lining (A) is excellent. A variable lock or step-lock knee hinge allows the child to spend time in varying degrees of extension (B).|
Figure 7. A very common need is to provide a knee extension splint for a child with CP, and most of these can be addressed with a foam wrap that includes metal stays and Velcro enclosures. These commercially available knee immobilizers are cost effective, comfortable for the child, and easy for the caretaker to apply and remove.
Ankle equinus is the most commonly recognized joint malposition in children with CP. Orthotic control of this equinus position has a long history and is the oldest treatment of the motor impairments of CP. The availability of modern thermoplastics has greatly increased the options for orthotic management compared with the old heavy metal and heavy leather shoe devices. The plastic braces provide a much larger skin contact, so the forces from significant spasticity are distributed over a larger surface area and are better tolerated. Because of wide size and shape variation of the feet in children, most of these orthotics should be custom molded for the best fit (Figure 8). The use of AFOs includes many different variations, and all the published studies have confirmed the mechanical effects of these orthotics. For example, if the ankle is blocked from going into equinus by the orthosis, there is decreased ankle range of motion and decreased ankle equinus. These same studies do not show predictable effects at joints not covered by the orthotic. Also, if the orthotic has a hinge that allows dorsiflexion, there is more dorsiflexion present than when the orthotic has a fixed ankle. There are no data to suggest that one type of orthotic or different design is better than any other. The concept of pressure points in specific molds to reduce muscle tone has no objective data to support their use. There is objective evidence that these orthotics can improve children’s balance ability. Balance may be better with hinged AFOs than with solid AFOs.8 Others have found no difference between hinged and solid AFOs, or between hinged and solid AFOs and tone-reducing designs.9 There is improved stability in the stance phase of gait10, 11 and improved ankle position in swing and at foot contact.12 Also, improved stability by the use of AFOs in children who are coming to stand in the preambulatory phase has been documented.13 Based on these limited objective data, most specific prescriptions for foot orthotics require a consideration of the skills of the available orthotist and the specific mechanical goals desired in the individual child.
The terminology used in describing specific components of AFOs is very confusing. The term dynamic is used in the literature to mean an AFO with a hinge joint at the ankle; however, it is also used to mean a solid plastic AFO made of thinner, more flexible plastic that wraps around the limb to gain stability. Tone reducing is another term that is widely used but has no specific standard meaning. To avoid confusion, the terms dynamic and tone reducing are not used further in this discussion. Hinged or articulated will be used to mean an orthosis that contains a joint at the ankle, and the term wraparound will be used to refer to the thinner plastic with a fuller circumferential mold.
A B C D
Figure 8. Because of the wide variation in foot size and shape in children with CP, AFOs usually should be custom molded for the best fit and tolerance. This process starts with application of a stocking on which specific bone landmarks are outlined so the mold can be later modified to prevent pressure on these areas (A,B). Next, either a premolded plantar arch mold is applied or the arch has to be molded by hand (C). Plaster is now rolled over the foot using an anterior rubber bolster to protect the skin for cast removal (D).
A solid AFO with an anterior calf strap and an anterior ankle strap is the most versatile orthotic design and is the orthosis most often prescribed for children at the preambulatory stage, usually between the ages of 18 and 24 months (Figure 9). This orthotic provides stability to the ankle and foot to give a stable base of support for children to stand. This orthosis is reasonably easy for caretakers to apply and is lightweight. As children gain better stability and start to walk using a walker, usually between the ages of 3 to 4 years, the ankle hinge can be added to allow dorsiflexion but limit plantar flexion. This transition to a hinged AFO is contraindicated if children have severe planovalgus or varus foot deformity (Figure 10). The hinge will allow movement through the subtalar joint rather than the ankle joint and, as a consequence, will allow worsening of the foot deformity in the orthosis. Also, the hinged AFO is contraindicated if the children are developing increased knee flexion in stance or a crouched gait pattern. Most children who have good walking ability with diplegic and hemiplegic pattern involvement benefit from the transition to a hinged AFO at approximately 3 years of age. Most children who are marginal ambulators or nonambulators will be best served by staying in solid AFOs. Hinged AFOs are preferred for children who back-knee because of gastrocnemius contractures. By setting the plantar flexion stop at 5° of dorsiflexion, these children will be forced into knee flexion in stance if they are independent ambulators. If they use assistive devices, such as walkers or crutches, they may still backknee by allowing the forefoot to come
Figure 9. The most basic AFO has a solid ankle, an anterior ankle strap, and an anterior calf strap. This is the preferred orthotic for preambulatory children and most marginal ambulators.
Figure 10. As children gain ambulatory ability and the main goal of the orthotic becomes preventing plantar flexion, a plantar flexion-limiting ankle hinge joint can be added. The remainder of the orthotic is similar to the solid ankle, with perhaps a flat sole or additional arch molds added. These tone-reducing features have not been shown to change gait in any measurable way.
Figure 11. The solid ground reaction AFO is entered from the rear at the calf level. This is an anticrouching orthosis and has very specific requirements to work. The knee must be able to fully extend, the ankle has to be able to dorsiflex to neutral with an extended knee, the foot progression angle must be within 30° of neutral, and the tibial torsion must be less than 30°. This orthosis depends on the action of the ground reaction force, and as such is only effective when the child stands or walks and if the child has enough weight, usually 30 kg or more.
off the floor. If this occurs, the shoe should have a good wide stable heel; however, in spite of this, some children will persist with back-kneeing and can be controlled only with a KAFO that blocks knee hyperextension directly.
Controlling crouched gait with increased knee flexion and ankle dorsiflexion in stance phase is best done using solid AFOs with wide anterior proximal calf straps until children weigh 25 kg, usually at about 8 to 10 years of age. For children who are over 25 kg, the solid ankle ground reaction AFO, which is rear entry in the calf, is recommended (Figure 11). The use of this orthosis requires that the ankle can be brought to neutral dorsiflexion with the knee in full extension. If this cannot be accomplished, the orthosis cannot work and these children first need gastrocnemius and hamstring lengthening before the orthosis can be used successfully. The successful use of this orthotic requires that there be very little knee flexion contracture. Because this orthosis depends on the mechanics of an effective ground reaction force, the foot-to-knee axis has to be in a relatively normal alignment, meaning less than 20° of internal or external tibial torsion. This solid ground reaction AFO does not work with severe internal or external tibial torsion or severe foot malalignments. The ground reaction AFO only works when children are standing on their feet, and as such is useful only for ambulatory children. As these children get heavier, this orthosis becomes more effective; however, it also has to become stronger. As children approach 50 to 70 kg, the orthosis has to be constructed with a composite of carbon fiber or laminated copolymer to withstand the applied forces.
The ground reaction AFO may be hinged to allow plantar flexion but limit dorsiflexion (Figure 12). This orthosis is primarily used after surgical reconstruction of the feet and muscle lengthening as a bridge to allow development of increased muscle strength in the plantar flexors, with the long-term goal of individuals being free of an orthotic. However, some individuals continue to use this articulated ground reaction orthosis long term. The orthosis can be used before surgery on rare occasions; however, a prerequisite for using articulated ground reaction AFOs is normal foot alignment. The articulated ground reaction AFO is entered posteriorly into a circumferentially molded forefoot, but with no hindfoot control. If there is any planovalgus or varus hindfoot deformity, the foot will deform even more severely into planovalgus or varus under the strong force of the ground reaction moment. Because this articulated ground reaction AFO contains no resistance to prevent deformity, the orthotic is usually not tolerated because of significant skin pressure on the forefoot when any degree of planovalgus foot deformity is present. Older children weighing more than 25 kg who meet the other criteria will usually be very comfortable with the articulated ground reaction AFO, and the orthotic will be very effective in controlling crouched gait. However, it must be emphasized that this orthosis works only when all the indications are appropriate. Another option for using the articulated ground reaction AFO that may be useful in younger children who weigh less than 20 kg is to use the standard articulated AFO and then attach a posterior restraining strap, which prevents dorsiflexion at a certain predetermined amount (Figure 13). Often, these restraining straps are made of a fabric material and stretch over time, so they have to be reset fairly
|Figure 12 B|
|Figure 12 A|
|Figure 12. The ground reaction concept can also be applied with the goal of increasing ankle plantar flexion while preventing crouching. This requires an orthosis that limits dorsiflexion and allows plantar flexion.The use of this rear-entry orthosis has all the requirements of the solid ankle ground reaction AFO, and in addition requires that there be no foot deformity (A). Because the rear entry does not allow any orthotic control of the hindfoot, varus or valgus foot deformities make this orthosis not useful. The most common reason to use this orthosis is following surgical reconstruction of severecrouch gait, in which the planovalgus was corrected and the goal is to gain improved plantar flexion strength with the eventual goal of the child becoming brace free (B).
Figure 13. There are a group of children who are smaller, especially with some planovalgus foot deformity, in whom some ankle motion is thought to be beneficial. One alternative is to use a standard articulated AFO and attach a posterior restraining strap to prevent hyperdorsiflexion. Although this seems like a good goal, unless the child is very light, there does not seem to be any cloth material that can be attached to the orthotic that doesnot rapidly stretch out.
frequently. This design never works for heavy adolescents because there is no orthotic material that is strong enough to resist the force of dorsiflexion from the ground reaction AFO.
The use of a solid AFO without an anterior calf strap is a design to control plantar flexion that will allow free dorsiflexion (Figure 14). If children use considerable dorsiflexion, their calves move away from the shank of the orthosis and can be very uncomfortable. Because it is uncomfortable when the calf presses against the edge of the orthotic shank, these solid ankle AFOs without anterior calf straps are usually cut low to only half the normal calf height. This design works well if children have very mild plantar flexion force and mainly need a gentle pressure reminder to prevent plantar flexion in swing phase or early stance phase. This design is contraindicated if there is strong plantar flexion spasticity or significant stance phase-back kneeing, as the orthosis does not provide adequate mechanical control of the ankle to control these deformities. Also, the half-height design can cause a high-pressure area in the posterior aspect of the calf, leading to a fracture of the subcutaneous fat and a permanent transverse line on the middle of the posterior calf (Table 6.1). Also, some children are irritated by their pant legs getting pinched between the orthotic and their skin. This half-height AFO brace design is very useful in middle childhood at a point when children almost do not need an orthosis, but
|Figure 14. The use of a short calf segment with no anterior calf strap is an alternative to an articulated AFO. This design works well if the plantar flexion force is mild and the child just needs a little reminder to stay out of plantar flexion. If the child has strong plantar flexion, the calf segment will gradually erode a crease in the subcutaneous fat and can leave a permanent crease in the calf.|
still have a tendency to back-knee or to intermittently walk on their tiptoes.
Wrap-Around AFO Design
Other specific design features include the choice of the material for the orthotic. Most children’s AFOs are custom molded and made of high-temperature, vacuum-formed thermoplastics. This material is available in several thicknesses, with a thickness chosen by the orthotist to meet the perceived demands based on the size of the individual child. Most commonly, this orthotic covers the posterior half of the calf and plantar aspect of the foot. The orthotic can be customized further with soft pad inserts (Figure 15), and it has some limited ability to be expanded by the orthotist by heating the material or being able to weld material on at the end of the toe plate or at the shank. Most of these orthotics can be made to fit for 12 to 18 months in growing children. Another design that has recently gained popularity is the use of a thinner thermoplastic plastic, which wraps circumferentially around the limb (Figure 16). The strength of the orthosis is gained from the circumferential wrap. This thin plastic tends to be more flexible and therefore deforms slightly when force is applied. Also, the circumferential wrap tends to apply a wider contact area to the skin, often distributing forces over a larger area of skin. The negative aspects of this thin plastic wrap-around technique is that the orthotic is difficult to apply to uncooperative children because caretakers have to use two hands to open the orthotic and to apply it to the foot. Also, it is difficult for some children to self-apply this orthotic for this same reason. Because the plastic is very thin and closely conforming, it cannot be modified for rapidly growing children and in some situations will only fit for 6 to 9 months. Because the plastic is also not very strong, it cannot be used in high-stress situations like ground reaction AFOs.
|Figure 15. The solid AFO design can be modified by adding softer inside pads toprotect bone protrusions or pressure areas.
Figure 16. An orthotic design that uses a thinner, more flexible plastic with a circumferential wrap can be used for many of the different designs. Its major limitation is that the thin plastic is weaker and gains strength by the circumferential wrapping nature of the design. It does not work for highstress environments, such as ground reaction AFOs, and can be difficult to put on and take off, especially for children just learning to dress themselves.
Anterior Ankle Strap, the design of the anterior strap is another variable feature, with some methods working better than others. All AFOs made for individuals with spasticity need an anterior ankle strap. For children with strong plantar flexion spasticity, the ankle strap should be fixed at the level of the axis of the anatomic ankle joint, then brought to the opposite side through a D-ring and wrapped back on a Velcro closure (Figure 17). This method proves to be the strongest direct force to control the plantar flexion. A figure-of-eight strapping may be used as well; however, this does not provide very strong control over the anterior ankle, although it does distribute the force over a larger area of skin. If children have varus deformity of the foot, the strap should be fastened on the inside of the lateral wall of the orthotic and brought through a medial D-ring. If the foot has a valgus deformity, the strap should be attached on the inside of the medial wall of the orthotic and a lateral Dring should be used. There are many variations of molds on the sole of the foot, none of which have any documented objective benefit (Figure 18). Some of these molds seem to make some subjective difference. Using an elevated toe plate seems to decrease the plantar flexion push in some children and helps in rollover in the forefoot in terminal stance in other children who are very functional ambulators. The only drawback of the elevated toe plate design is the difficulty of extending the orthotics to increase wear time because of growth. Also, the elevated toe plate cannot be moved once it is molded into place. Contouring for a medial longitudinal arch, a distal transverse arch, or a lateral peroneal arch is used by some orthotists. So long as these contours are not excessive, they may help to stabilize the foot
|Figure 18. The degree of contouring and molding of the plantar surface of the orthotic inspires a lot of discussion and strong feelings; however, objective data currently donot suggest that it makes much difference.The tone-reducing features are varied; however, they tend to include some combination of transverse metatarsal arch, medial arch, peroneal arch, and transverse calcaneal arch
(A,B). When comparing the relatively flat sole often used (C) with the highly contoured sole, there is minimal functional difference. The same benefit can also be obtained by adding pads to the inside of the orthotic using a soft plastic (D). These pressure areas can also be molded directly into the orthotic. Some also like to square off the heel on the outside to give better control of the orthotic in the shoe
(E). This feature makes application of the shoes harder than leaving the heel rounded, and less contouring on the toe plate allows easier extension of the orthotic as the child
and makes shoe fitting more difficult (F grows. Another technique used is to flatten the sole externally with a rubber material; however, this increases the height of the orthotic).
|Figure 17. AFOs made for children with spasticity need a good stable anterior ankle strap that is directed across the axis of the ankle joint. One of the best options is a padded anterior ankle strap that loopsthrough a D-ring fixed on the side opposite the main deforming force (A). If the child has a planovalgus foot, the D-ring is lateral and if the foot is varus, the D-ring is medial; this
allows using the D-ring to provide leverage to tighten the strap and allows the Velcro to hold better (B)
C D E F
in the orthotic, but they provide little other benefit that we can identify and no benefit that can be measured objectively.6 The distal extend of the orthotic has to be specified in the prescription.
Almost all children with spastic deformities should have the orthotic extend to the tips of the toes to provide control of toe flexion. Almost all children with spasticity tend to have a toe flexor response when there is stimulation on the plantar aspect of the toes. The toes tend to always flex as if they were trying to hold or grab onto something. This is often the first area where children outgrow the orthotic and is the primary area that needs to be monitored for adequate AFO size. Children with hypotonia or predominantly ataxia often need only a distal extend to the base of the metatarsals or the base of the toes. In these hypotonic or ataxic children, there can be a detriment to extending the orthotic because it makes rollover in late stance phase more difficult.
Orthotics that do not control plantar flexion and dorsiflexion of the ankle are called foot orthotics. None of these orthotics has any impact on ankle plantar flexion or dorsiflexion.6 The role of these orthotics is to control deformities of the foot, mainly planovalgus and equinovarus deformity. These orthotics are primarily used in children with hypotonia, or in middle childhood
and adolescents with spastic foot deformities. The supramalleolar design extends above the ankle on the lateral side with the goal of controlling varus or valgus deformity (Figure 19). The foot orthotic can have all the same design features and options that were discussed in the section on AFOs. Usually, an anterior ankle strap is used; however, in some older children with good ankle plantar flexion control, this is not needed. Also, the heel is typically posted on the side opposite the deformity. This means a lateral squaring of the heel is added for varus deformity so the ground reaction force will tend to counteract the deformity. The opposite is done for valgus deformity, in which a post is added to the medial side of the heel. This supramalleolar foot orthotic design also works well with the wrap-around thin plastic design;
|Figure 19. In-shoe foot orthotics are used primarily to control planovalgus or varus foot deformities. These can be constructed with the wrap-around design (A) or with the solid plastic, which sits in the shoe (B). Both of these are supramalleolar type and provide support for the foot.|
however, the same problems occur as noted with the standard AFO. It is more difficult for children to don the orthotic, and heavy children tend to collapse the orthotic the same way a shoe deforms with long-term wear. There is no clear choice between the thin plastic wrap-around design and the solid plastic half-mold design. Input from the families and children should be considered as well as the preference of the orthotists. Most children who need control of planovalgus or varus, but have good plantar flexion and dorsiflexion control of the ankle, should be fitted with a supramalleolar orthotic (SMO). There are a few children, mainly those with hypotonia and ataxia, who have moderate planovalgus that is easily controlled but who can be fitted with an inframalleolar orthotic (Figure 20). This orthotic contains a good heel mold, a medial longitudinal arch mold, a heel post, and typically stops at the metatarsal heads proximally. These orthotics can be set into shoes, have no anterior ankle straps, and are very easy to don because they do not need to be removed from the shoe. Applying this orthotic is no more difficult than putting on children’s shoes. The use of this orthosis in spastic foot deformities is limited because of its limited ability to provide corrective force. Another name that is used for this inframalleolar orthotic in some locations is a “University of California Biomechanics Laboratory” (UCBL) orthotic.
|Figure 20. For feet that need only mild support, an in-shoe arch support can be constructed, again either with the wrap-around thin plastic, or the heavier, no-deforming material;these are commonly called inframalleolar orthotics or “University of California Biomechanics Laboratory” (USBL) orthotics.|
Postoperative Hip Orthoses
Traditionally, after hip reconstruction surgery for children with CP, hip spica casts have been applied and set at 30° of unilateral hip abduction (combined 60° angle) and 30° of hip flexion. Hip spicas take considerable time to apply at the end of an often already lengthy surgery; preclude visual inspection of the surgical wounds during the postoperative period; and can cause complications such as pressure sores. Other disadvantages of hip spicas are the need for intensive physiotherapy and usually hospital readmission to regain ranges of hip and knee joint motion that will have stiffened from immobility in the cast. The use of an orthosis in these instances may overcome some of the complications associated with using hip spica casts. The most suitable design in these instances includes a pelvic section connected to the thigh cuffs with an orthotic joint that allows incremental adjustment of flexion and abduction that can be adjusted and locked in the selected position (Figure 5).
Lower Limb Deformities
Prestanding children will spend much of their time sitting and are therefore predisposed to contractures of the muscles of the lower limb. Many of the major muscles around the hip, knee, and ankle actually cross two joints. For instance, the major bulk of the calf muscle is the gastrocnemius, which crosses both the ankle and knee. To provide an efficient stretch of the gastrocnemius, preventing plantar flexion must be augmented with an orthosis to extend the knee. This may be achieved simply by simultaneously using a rigid ankle foot orthosis (AFO) and a stiffened fabric knee gaiter for short periods. Deformities of the hind- and mid-foot can develop when the range of dorsiflexion available at the ankle is reduced either by spasticity, muscle shortening, or both. Mobile equinovalgus and equinovarus ankle foot deformities can be corrected during the mold taking and cast rectification process and the position maintained using close fitting rigid AFOs. Fixed deformities, however, must be accommodated in their best corrected posture. Persistent ankle and knee deformities secondary to spasticity may benefit from intramuscular injections of botulinum A toxin to weaken spastic muscles, often combined with short periods of serial casting to facilitate ongoing management in orthoses. Maintaining reasonable foot and ankle posture will enable more comfortable posture in seating systems by allowing some of the weight of the lower limbs to be supported by footplates. If profound fixed ankle and foot deformities become established, fitting of ordinary shoes can become a problem and custom-made footwear may be necessary.
Upper Limb Management
Inadequate fine motor control and coordination may impair manual dexterity and may lead to muscle shortening and reduced ranges of movement at the elbows, wrists, and fingers. Children with bilateral spastic CP may be more affected in their lower limbs with relatively useful function in the upper limbs (sometimes called diplegia), or have four limb (total body) involvement. The principles of orthotic management are the same as in the lower limbs (that is, to stretch tight muscles, sometimes in combination with botulinum A toxin injection and serial casting). Occasionally wrist hand orthoses (WHOs) may also be employed to enable or improve hand function. The prescription of functional WHOs remains controversial but may be useful to enable or improve hand function in conjunction with occupational therapy regimens to facilitate training in skills of dexterity (Figure 21).
|Figure 21. A dorsal wrist hand orthosis (WHO) with palmar bar and elastic Velcro straps stabilizes wrist extension enabling the child to focus on dexterity skills.|
Upper extremity orthotics are used almost exclusively to prevent deformity or reduce contractures. The most common use of upper extremity orthotics is in children with quadriplegic pattern involvement who develop significant wrist and elbow flexion contractures. Using orthotics to stretch against these deformities may slow the development of more severe contractures; however, objective evidence to support this concept is not well documented. There is little or no harm from the use of these orthotics so long as the children are not uncomfortable and there is no skin breakdown caused by the orthotics. From a rationale perspective, the use of these orthoses during the adolescent growth period makes some sense. The orthotics may stretch the muscles and provide some stimulus for them to grow if the stretch can be maintained for many hours each day. The exact amount of time an orthotic should be worn to be beneficial is unknown, but 4 to 8 hours of brace wear a day are probably required. Very few children get functional benefits from the use of upper extremity orthotics. Sometimes a very small thumb abduction orthosis will allow a child to hold a toy with finger grasp, which she could not do with the thumb in the palm. The benefit of upper extremity orthotic wear is not documented the determining factor. For example, if a child has a thumb-in-palm deformity that can be corrected with a thumb abduction orthotic but she refuses to bear weight or use the hand when the orthosis is applied, the orthotic should be abandoned.
There are no useful orthotics for the shoulder. Attempts at abduction bracing of the shoulder are uniformly unsuccessful. An occasional child will have an abduction external rotation contracture of the shoulder with athetoid movement or spasticity that can be controlled using a wrist band and securing the forearm to the waist belt or lap tray of the wheelchair. Some children also develop shoulder protraction, and occasionally a parent or therapist will want to try a figure-of-eight shoulder retraction orthosis; however, the strength of this protraction cannot be overcome with a figure-of-eight shoulder orthosis because of its extremely poor mechanical advantage.
The principal deformity at the elbow that is amenable to bracing is flexion. In children with strong spastic flexion deformity, the use of a bivalve custommolded high-temperature plastic orthotic is required. The use of fixed dial locks allows these orthotics to be placed in different degrees of flexion depending on the tolerance of the individual and their skin. Sometimes individuals can tolerate more extension on one day and less on the next. If the spasticity is weaker or the children are less than 10 years old, a low-temperature plastic orthotic that is molded to the flexor surface of the elbow with straps around the olecranon is simpler and much cheaper to construct. Usually, these orthotics are fabricated by an occupational therapist, and they can also be easily modified with a low-temperature heat gun if more or less flexion is required. There has been a recent commercial promotion to use elastic hinges at the elbow, which have continuous passive stretch on the elbow. No objective data exist to support this concept, and the standard teaching is that spastic and elastic do not mix. This saying comes from the usual finding that a constant elastic stretch on a spastic muscle usually continues to initiate the spasticity. A fixed stretch will allow the muscle to slowly relax and stop contracting. However, this dogma is not well substantiated by objective testing. Pronation contractures are very common in the forearm of children with spasticity. There are no orthotics that can effectively control a spastic forearm pronation deformity, although trying
|Figure 22. Using a soft foam material with Velcro closures, a circumferential wrap can be designed to provide some supination (A) stretch along with wrist dorsiflexion and thumb abduction (B). Many children with strong pronation spasticity do not tolerate these wraps.|
|Figure 23. A splint that is entirely volar based can provide finger support or have the fingers free. This splint is very easy for caretakers to apply.|
circumferential wraps are usually not uncomfortable for the child with a mild deformity(Fig.22).
Wrist and finger flexion combined with thumb abduction and flexion are very common deformities in children with CP. Wrist extension orthoses are used mainly after surgical reconstruction to protect the tendon transfers for some additional months after cast immobilization has been discontinued. Usually, these orthotics are volar splints, which maintain the wrist in 20° to 30° of wrist extension and are worn full time (Fig.23). These wrist splints seldom provide a functional benefit to children and are usually poorly tolerated for long-term use. In children or adolescents with hemiplegia, there is a major cosmetic concern about the appearance of the limb. The orthotic provides no functional gain and is very apparent; therefore, it is usually cosmetically rejected. Most children with good cognitive function object to wearing a wrist orthosis for more than a short postoperative period. A dorsal wrist extension splint is sometimes better tolerated; however, there is no apparent improvement in function over the volar splint. The benefit of the dorsal splint is that it covers less of the palm and volar surface of the wrist and should therefore make more sensory feedback available to children during functional use. The disadvantage of the dorsal splint is that the force in the palm to extend the wrist is applied over a much smaller surface area, and if high force is required because of strong spasticity, the skin will often become irritated or develop breakdown.
Resting hand splints, in which the wrist and fingers are all maximally extended to the comfort level of individual children, are good splints to help stretch the forearm muscles during the adolescent growth period. This splint may be made with a dorsal or volar forearm component (see Fig.23). The dorsal forearm component is easier to stabilize on the arm; however, it is often harder for caretakers to apply. The opposite is true if a volar forearm component is used. The resting hand splint can incorporate thumb abduction and extension as well as finger abduction (Fig. 24). Often, children tolerate these splints poorly immediately after initial splint construction. However, if the wear time is gradually increased, a goal of 4 to 8 hours per 24-hour period can often be achieved. This goal is ideal if children can tolerate the orthotic for this length of time; however, it is still worthwhile even if they can only tolerate the orthotic for 2 to 4 hours per day.
|Figure 24. A dorsal-based resting hand splint will provide wrist dorsiflexion, finger extension, thumb abduction, and correction wrist ulnar deviation (A, B). The splint tends to be easy for caretakers to apply and is comfortable if no excessive stretch is applied at the time of construction. For postoperative support, the dorsal-based wrist extension splint is used during the day so that the child can start using active finger flexion.|
|Figure 25. Thumb abduction splints can be constructed from a number of materials. Using low-temperature plastic, a well-molded splint can be formed (A).|
Thumb abduction and flexion is another common deformity. In most cases, this thumb deformity is combined with finger flexion and wrist flexion contractures, especially in children with quadriplegic pattern CP; therefore, the thumb deformity can be splinted using the global resting hand splint. For younger children with hemiplegia, thumb abduction can make finger grasp difficult. Using small, soft thumb abduction splints or low-temperaturemolded abduction splints (Fig. 25), the thumb can be positioned out of the palm in such a way that children can develop finger grasp. These splints should be limited to the absolute minimal amount of skin coverage possible because all skin coverage will reduce sensory feedback and the children will
tend not to use their extremity.
Swan Neck Splints, extensor tendon imbalance in the fingers may cause the fingers to become locked, with hyperextension of the proximal interphalangeal joint (PIP). This imbalance is most common in the long and ring fingers but occasionally occurs in the index finger. A metal or plastic figure-of-eight splint to prevent this hyperextension can be made (Fig.26). Usually, a plastic splint is used first and, if individuals find the splinting function beneficial, a metal splint is made, which is very cosmetically appealing because it looks like a cosmetic finger ring. In some individuals, these rings become uncomfortable because of the amount of force that the ring exerts over the very narrow area of skin. It is this narrow skin pressure that may limit the use of ring orthoses.
|Figure 26. Finger proximal interphalangeal joint (PIP) joint hyperextension can be a difficult problem that is easy to control in some individuals with extension block splints. One type of commercially available splint is plastic-covered wire (A), and another common type is a molded figure-of-eight type plastic orthotic (B).|
The terminology for prescribing orthotics can be confusing. The most general rule for spine and lower extremity orthotics is that the orthosis is named for the joints that are crossed by the orthotic. For example, an orthosis that covers the ankle and the foot is called an ankle-foot orthosis (AFO). Often, modifiers are added to make the name more specific. For example, the term molded may be added to AFO, which then becomes a molded ankle-foot orthosis (MAFO). The term MAFO is used to describe a plastic brace made from a mold produced from a cast of a child’s extremity where the orthotic is to be fitted. Sometimes functional modifiers are added, such as ground reaction AFO (GRAFO), to describe an orthotic used to prevent knee flexion in the stance phase of gait. Upper extremity orthotics more commonly carry functional terms, such as a resting hand splint or a wrist orthotic. Many of these orthotic names are very regionally specific or in fashion because of specific marketing campaigns by orthotic manufacturers, and thus change over time.
GMFCS Level II Before Age 2 Years, Level III After Age 2 Years, and Level IV After Age 4 Years
The objectives of orthotic management for the standing child are the same as for the prestanding child, with the additional goal of facilitating an efficient upright posture with the minimum appropriate external support. Standing, even for the nonambulant child, may be beneficial for the body structure by increasing bone density.The activity of standing is also important for stretching muscles and other periarticular tissues and to allow children to experience the world from the same eye-level as their peers. The level of each child’s individual activity limitation will necessarily determine the degree and type of external support required. Clinical examination should therefore additionally include appraisal of the standing posture and balance assessment.
For most impaired children who will achieve standing (GMFCS Level IV), a hip knee ankle foot orthosis (HKAFO) will be required to maintain an upright posture, simulating Chailey Level 4 for standing ability. Two three-point force systems are used to prevent hip and knee flexion: applied to the anterior chest, posterior sacrum, anterior knees, and posterior heels. This may be fixed to a broad support base as a standing frame and used with a tray at an appropriate height. If children are able to generate adequate hip extension power, then the chest strap can be removed for short periods. Children will often require support of the ankle and foot to provide stability at the foot-floor interface during standing. Spastic equinus and any secondary hind- or mid-foot valgus or varus can either be corrected or accommodated in rigid AFOs. Heel wedges can be used to alter the inclination of the lower leg relative to the floor to accommodate fixed flexion of the hips and knees or fixed equinus.
Children who are able to pull themselves upright and maintain standing independently by holding on to an anteriorly placed piece of furniture may still benefit from some external support (GMFCS Level II before age 2 years, Level III after age 2 years). Orthoses that restrict ankle motion can be used to provide a stable base and control the line of action of the ground reaction force around the hip and knee so that training and strengthening can be targeted at proximal muscles.
In a study of standing balance, the center of pressure under the foot was shifted more anteriorly for children with spastic equinus than for normal children, as would be expected.29 Using footwear and AFOs that resisted plantar flexion enabled the children to shift the center of pressure more posteriorly but had little effect on lateral sway characteristics. Another small study compared four children with CP with four healthy children during perturbed standing balance while barefoot and with rigid and spiral graphite AFOs.30 This study demonstrated the difficulty children with CP have in recruiting muscles to maintain balance and indicated that rigid AFOs can impose further difficulties by removing the postural adjustments that can be made at the ankle. In other studies that have examined the activity of moving from sitting to standing, children with CP and spastic equinus who were slower than healthy children performed the task faster with either rigid or hinged AFOs (perhaps GMFCS Levels II and III). However, similar children who were within 1 standard deviation of the range of normal children in achieving the task barefoot were slower when using either design of orthosis (perhaps GMFCS Level I).31 Therefore, permitting small amounts of movement at the ankle may enhance standing balance and enable the child to move from sitting to standing more easily. Children who achieve independent standing can then focus on developing skills of walking, perhaps requiring ongoing assistance of orthoses and walking aids (GMFCS Levels III and IV).
GMFCS Levels I, II, and III After Age 2 Years and Level IV After Age 4 Years
Approximately two thirds of children with CP will achieve some level of walking ability.32 The objectives of orthotic management for the walking child are the same as for the prestanding and standing child, with the additional goal to enable the child to attain an efficient and purposeful gait. In addition to the information required in the clinical examination of prestanding and standing child, an assessment of the child’s gait is necessary. The gait of children with spastic type CP is generally repeatable from step to step. However, children with ataxic or dyskinetic types of CP may be more variable and less predictable. Gait analysis requires a systematic approach to describe the patterns of joint motion and identify factors that cause pathological movements. The difficulty in analyzing the gait of children with CP is that the impairment causes gait deviations in each of the sagittal, coronal, and transverse planes and commonly involves the hip, knee, and ankle joints.
Winters’33 classification for children with spastic hemiplegia identified four distinct patterns with increasing distal to proximal involvement. For Winters Type 1 hemiplegia, which presents as equinus only in swing phase, either a posterior leaf spring or hinged AFO with a plantar flexion stop may improve foot ground clearance. For Winters Type 2 hemiplegia, when equinus persists in stance and swing phase and the knee is hyper-extended during stance, a rigid AFO is recommended. For Winters Types 3 and 4, when additional knee and hip pathology exists, orthotic management is insufficient and orthopaedic surgery is indicated.
Sutherland and Davids identified four patterns of knee motion in spastic diplegia. In combination with Winters classification, these patterns have been used to create algorithms for physical management that combine appropriate use of spasticity, musculoskeletal and orthotic interventions.35 Recommendations for orthotic intervention to improve gait efficiency are usually based on the integrity of the plantarflexion-knee extension couple during stance phase. This describes the normal relationship between the ankle-foot complex and the knee joint to maintain the ground reaction force (GRF) just in front of the knee during stance phase. It requires the ankle and foot to be stable, leading in the line of progression and the gastrocnemius and soleus muscles functioning to control tibial advancement.
Children with spastic type CP commonly walk with ankle equinus. Making initial contact with the forefoot during walking will usually cause the line of action of the 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 AFOs that prevent plantarflexion 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 (Figure 4 ).
|Figure 4. A: Making initial contact with the forefoot, secondary to spastic equinus, creates abnormal movements around the knee and hip joints, causing knee hyperextension. B: Rigid AFOs that prevent plantarflexion can alter the line of action of the GRF to reduce the external moment. C: Depending on the pitch of the shoe, fine tuning with heel wedges can further enhance the efficacy of the orthosis by tilting the knee joint anterior to the GRF.|
|Figure 5. A: When the GRF passes posterior to the knee, the external movement will cause excessive knee flexion and crouching. B: AFOs that prevent dorsiflexion at the ankle can prevent knee flexion during stance by realigning the GRF in front of the knee to assist extension|
For children with more severe impairment, spasticity of proximal muscles will cause the knee and hip joints to remain flexed during stance.11,33 When the GRF passes behind the knee, the increased external flexion moment will cause excessive knee flexion and crouching. AFOs that prevent dorsiflexion at the ankle can prevent knee flexion during stance by realigning the GRF in front of the knee (Figure 5 ). However, whereas these orthoses are effective for paralyzed limbs, the presence of spastic or fixed flexion at the knee and hip joints means that other interventions are required to render these orthoses effective in children with CP. We routinely use anterior GRF AFOs, extending proximally to the tibial tubercle, in the 6 months’ postmultilevel surgery to protect the weakened muscles and enable early standing and walking.
In either of the above situations, the rigid lever of the ankle and foot must also cope with premature and prolonged external dorsiflexion moment. The multisegmental structure of the ankle and foot may buckle due to the applied forces, causing hindfoot eversion or inversion and mid-foot collapse. In these circumstances, apparent dorsiflexion will occur at the expense of the structure of the ankle and foot. Therefore, when the integrity of the ankle and foot is insufficient to maintain a rigid lever, and the hind and mid-foot is at risk of deformity, it may be as important to prevent dorsiflexion as well as plantar flexion using a rigid AFO.
Because clinicians are aware that restrictive orthoses may impose additional activity limitations, orthoses should continue to facilitate, where possible, normal patterns of joint motion. Many studies have therefore attempted to compare the efficacy of rigid, hinged, PLS, and supramalleolar AFOs. A recent review of the efficacy of orthoses for children with CP could only conclude that preventing plantar flexion improved gait efficiency. Preventing plantar flexion has been shown to improve stability in stance phase, clearance in swing phase,41 prepositioning in terminal swing42 and to increase step length and walking speed.There is a suggestion that preventing plantarflexion may also improve energy expenditure based on oxygen consumption.
There is no evidence to support any tone-reducing effect on gait from orthoses that incorporate specially molded footplates.45 Therefore, the prescription of supramalleolar orthoses that provide no leverage to prevent plantar flexion would seem to offer little benefit in the goal to improve gait efficiency. However, supramalleolar and foot orthoses may be beneficial to children with dyskinetic or ataxic types of cerebral palsy whose sagittal plane gait deviations are an essential mechanism for achieving ambulation or indeed for children whose equinus during gait has been improved after surgery.
Coronal and Transverse Plane Gait Deviations
Gait deviations in the coronal and transverse planes are more difficult to distinguish than those in the sagittal plane using only observational gait analysis. Leg-length discrepancy (LLD) in children with CP, which is associated with hemiplegia, asymmetrical involvement, or hip subluxation, causes either compensatory excessive flexion of the longer limb or pelvic obliquity. Pelvic obliquity caused by LLD results in true hip adduction on the longer limb and hip abduction of the shorter side and can be corrected using a shoe raise.
Pelvic rotation, torsional abnormalities, or foot deformities can change the angle of the foot in relation to the line of progression (in- or out-toeing). Apparent rather than true hip adduction occurs when internal rotation is seen in conjunction with flexion, causing the knees to come together when viewed in the coronal plane (sometimes called “scissor” gait). This occurs frequently in children with CP because of persistent skeletal anteversion of the femur, and for ambulant children is more common than true hip adduction or internal rotation at the hip joint. Hip abduction orthoses for ambulant children may therefore be of little benefit.
Although it may be possible to harness shear forces from the skin and the shape of the soft tissues to gain some rotational control using a molded thigh cuff, in general, rotational control of the hip joint using orthoses requires extension to the foot. Orthoses incorporating a flexible torque cable within the thigh segment of a HKAFO or elastic bands wound around the limb attached to AFOs create active rotational forces and can alter the foot progression angle.47 However, when the cause of internal hip rotation is persistent femoral anteversion or spasticity, twister orthoses are not advised because the applied torque can lead to excessive strain on the soft tissues of the knee joint. Therefore, torsional deformities usually require a surgical solution. In- or out-toeing may also result from excessive pelvic rotation or foot deformity when there may be no torsional component in the long bones. Mobile deformities of hindfoot inversion with associated forefoot adduction and hindfoot eversion with associated forefoot abduction can be corrected during the casting process and controlled using AFOs. Pelvic rotation, in which the child leads with the less impaired limb, is part of the primary neurological impairment and cannot be influenced by orthotic management.
EVIDENCE TO SUPPORT ORTHOTIC INTERVENTION
To date, all published studies examining the efficacy of orthoses for walking children with CP have included small numbers of children, and all but one48 have used within-subject comparison research designs. The evidence to support specific orthotic interventions for children with CP remains to be demonstrated using more robust research methods, such as randomized controlled trials with appropriate follow-up periods. The difficulties in mounting randomized controlled trials in this population are well recognized, in that CP is a heterogeneous condition with a wide range of neurological impairment. Recruiting groups of children with comparable baseline characteristics into a trial can be perceived as an obstacle. The SCPE classification2 and the GMFCS4 now enable researchers to balance groups of children of comparable impairments and activity limitations. However, clinical trials that would demonstrate any moderate but statistical significant differences between treatment groups would require multicenter collaboration to recruit enough subjects.51 There is also the difficulty of ascertaining clear and simply measured outcomes. Separate treatment goals and outcome measures must therefore be defined in the body structure and activity dimensions. Other challenges to designing clinical trials are the inconsistent arrangements for the organization and delivery of orthotic services and the confounding effects of associated interventions. Perhaps the most difficult problems to overcome are the strongly held views of clinicians and families on the merits of different orthotic interventions that prevail in the absence of good evidence.
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