Health

Introduction to lower-limb deficiencies

Children born with congenital lower-limb deficiencies or who sustain lower-limb amputations as a result of trauma or disease may have a combination of various limb abnormalities. For instance, some children may have a normal lower limb on one side with a complete absence of the lower limb on the other side. Complete absence of a limb is referred to as amelia if it occurred congenitally. However, if the child was born normally but then had the lower limb amputated at the hip, then the child would be said to have a hip disarticulation. There are many more combinations of limb abnormalities. For instance, other children may have a shortened thigh bone or femur due to a longitudinal deficiency and have a normally developed ankle and foot attached to this. However on the opposite side only the shin bone may be absent. Some children may have necessitated an above-knee amputation on one side and a below-knee amputation on the opposite side. Each of these situations certainly can be unique and represent challenges that the child, family and rehabilitation team may face. However, with the appropriate education, resources and teamwork, these individuals can lead normal fun-filled lives with the ability to do anything they set out to accomplish.

What are some difficulties that face children with bilateral lower-limb deficiencies or amputations?

Children with bilateral lower-limb deficiencies face other hurdles that single-limb deficiencies don’t face. The first is that bilateral lower-limb amputees do not have a “normal” foot to contact the ground. This normal foot can be very helpful in sensing the position of the normal lower limb on the ground; positioning is very helpful for us to be able to balance ourselves as we stand and walk. Bilateral amputees who use prostheses do not have this capability. In fact, some bilateral limb amputees feel as though they are walking on stilts, which is in fact what they are doing. Therefore, it is common for children with bilateral lower-limb deficiency to use some other assistive device like axillary or Lofstrand crutches to improve their balance and help them walk.

Children with bilateral above-knee limb deficiencies will require locking knee joints until they are 6 years old. Ambulating on two mobile knee joints requires exceptional balance and strength, so the child may not be ready for this prosthetic change until that time. Parents should also realize that the amount of energy required to ambulate with any type of lower-limb prosthesis is greater than for a child without any deficiency in the lower limbs. In fact, a child with an above-knee limb deficiency or amputation has to use more energy to walk at the same speed as a child with a below-knee limb deficiency, who in turn requires more energy than a child without any deficiency. This also means that any child with bilateral lower-limb deficiencies uses more energy than a child with one side affected, with the most energy being used by a bilateral, above-knee limb-deficient child.

Unfortunately unilateral or bilateral lower-limb amputees are sometimes fitted with prostheses of unequal length compared to their opposite limb. Unequal lower limbs can often contribute to other musculoskeletal problems such as hip and back pain. Therefore it is a wise to have limb lengths measured from time to time especially after initial use of a new prosthesis to ensure that a leg-length difference does not exist or develop.

What are some of the goals for an infant with a lower-limb congenital deficiency or amputation between birth and 6 months of age?

It is understandable that parents of infants with lower-limb amputations or who are born with deficiencies may have several concerns and questions regarding typical motor development. Although children with multiple limb deficiencies may have some delay in attaining typical milestones, others with fewer abnormalities may not be delayed at all. Infants with toe, partial foot or very low transtibial limb deficiencies or amputations such as a Syme’s amputation may not experience any significant functional limitations and may only need an ankle or partial-foot prosthesis with toe fillers in order to obtain normal childhood milestones. Others with higher limb deficiencies or amputations may not have functional limitations in the first few months of life. In fact, not having a fully developed lower limb may enable the infant to be able to roll from their tummies to their backs at an earlier age than a child with normal lower limbs. Since any prosthesis should not hinder normal infant development, the goal of any first prosthesis is to attain the appropriate milestones, not hinder them. For these reasons, infants with lower-limb deficiencies should ideally be examined by a rehabilitation specialist or physical therapist within the first four weeks of life. In this way, a baseline examination can be obtained and various questions can be addressed that may assist in the development of the newborn or young infant.

With this general philosophy in mind, the first prosthesis for a child with a congenital lower-limb deficiency or amputation is typically tried at around 6 months of age. At this time, most infants have enough trunk control to begin sitting and may even be ready to pull themselves up to a standing position. This initial simple prosthesis will foster proper sitting balance by providing symmetrical weighting of the lower limbs while the child sits. This initial prosthesis will also enable the child to reach for objects nearby while encouraging play with others and develop social interaction. Physical therapy may consist of training both for the child and the parents, helping the child integrate the brace into activities such as rolling and lying. The infant may or may not prefer to use it when crawling. Since the child is not walking yet, the initial prosthesis will not have a knee joint built into it. Therefore, children may either crawl without a prosthesis or may elect to pull themselves along with their upper limbs since they will not be able to bend the knee of the initial prosthesis. (See Goals for 6 month old.)

Goals for infants up to 6 months old with lower-limb deficiency

• Begins to wear initial prosthesis
• Tolerates sitting with prosthesis (if needed)
• Begins to crawl with or without prosthesis
• Parents should don and doff prosthesis correctly, should observe for skin irritation and care for the prosthesis
• Parents should notify rehab team of any residual limb or prosthesis problems

What are some of the goals for an infant with a lower-limb congenital deficiency or amputation between 7 and 16 months of age?

Between the ages of seven and 10 months, a child begins to pull himself up to a standing position and eventually will walk somewhere between nine and 16 months. If a prosthesis is lightweight, of adequate length and comfortable to wear, the child may incorporate the prosthesis into the early stages of walking, which may entail furniture surfing and hand holding. A toy stroller, large exercise ball, walker or some other type of assistive device may also be tried in place of the furniture so that the child may start to practice walking. Normal walking involves a reciprocating rhythmic pattern of moving one limb past another and necessitates proper balance, weight bearing and strength. As the child becomes more confident and the gait becomes more normal, he will become comfortable and will fully use the prosthesis without anything to hold onto.

Although most toddlers at this age do not have a knee joint in their prostheses, if one is used it most likely will be a single-axis knee with a locking mechanism. This type of knee is extremely stable for the toddler taking his first steps but when he wants to sit or kneel, a button can be pushed or a cable pulled by the parent and the knee can be bent. A true mobile knee is typically not used until the child reaches 3 years of age.

As the child first learns to stand and walk, the prosthesis should be worn for short periods of time to allow for proper accommodation of the weight-bearing residual limb into the socket. The parents should again check the skin for abnormal pressure points that may appear with redness and/or swelling. It is during this time period that the prosthetist may allow the family to bring home a prototype or temporary prosthesis for a few days to see how the child reacts to it before making the final permanent prosthesis. In this way, regular physical therapy may be needed to assist the parents with various goals.

Goals for infants 7-16 months old with lower-limb deficiency

• Improves adaptation to prosthesis
• Prolongs wearing time
• Pulls to stand
• Furniture surfing
• Hand-held walking
• Improves sitting balance and crawling skills
• Parents should provide toys and activities that require the child to perform age-appropriate milestones
• Inspect for skin irritation and notify the rehab team for any issues such as skin irritation or prosthesis malfunction

What are some of the goals for toddlers with a lower-limb congenital deficiency or amputation between 17 months and 3 years of age?

Children at this time are becoming much more mobile and begin to develop more normal walking patterns. Additionally, they begin to climb stairs, jump and run. It is during this time that a mobile knee joint is integrated into the prosthesis and the child becomes more adept at walking and negotiating various terrains. Even though a prosthesis is used, the young child tends to rely on the normal limb to propel himself both in running and jumping. Climbing the stairs is a regular activity for most toddlers, but a child with an above-knee amputation or limb deficiency will do steps one at a time whereas a below-knee most likely will be able to climb them normally. The rehabilitation team should help the child and family learn how to achieve various milestones during this time including getting on and off chairs, getting up from the floor and getting in and out of a car as well as any other challenges that may arise during this transition period.

What are some of the goals for a child with a lower-limb congenital deficiency or amputation as they begin school and reach adolescence?

Most children develop a sense of self-identity by the time they reach school-age. Those born with a congenital limb deficiency realize that they are different before this time, making transition into school somewhat less traumatic. Children with newly acquired limb amputations, however, may need parental guidance and support during this age as they try to adapt into the school system. Meetings with teachers as well as the rehabilitation team may be fruitful in assisting with this transition. Athletic competition may be used as a means to encourage self-esteem, strength and confidence with the lower-limb prosthesis; however, it needs to be composed of more durable components.

During this age an alternative form of assistance, such as crutches, may be tried in place of the prosthesis. Typically, two types of crutches can be used for lower-limb deficient children: axillary or Lofstrand. Axillary crutches are the most familiar type of crutch and reach all the way up to the armpit or axillary area. The child should not bear weight on the axillary pad, as this can become uncomfortable after a while and may even lead to a nerve injury in the upper limbs. The other type of crutch is a Lofstrand crutch. This crutch does not go so high up on the arm and therefore does not provide as much support as axillary crutches. It is composed of a forearm cuff and padded hand bar attached to an aluminum tube. It is useful for these children to know how to use crutches so that when they have their prosthesis worked on, they do not need to rely on a wheelchair for transportation.