A Device for Ankle Physical Therapy for a Child with Leukemia

In 2005, about 1,790 U.S. residents were diagnosed with Acute Lymphoblastic Leukemia (ALL) (American Cancer Society, Inc. 2006). One third of every cancer case in children is diagnosed to be ALL. It is the most common disorder diagnosed in children, with peak ages between 2 and 5 years old (Satake 2006). ALL is a cancer of lymphoid white blood cells, the cells responsible for fighting infection in the body. Cancerous lymphoid cells cannot perform their usual function, so children with ALL get sick extremely easily because their bodies are not equipped to fight infections (National Cancer Institute 2002). The acute part of this disease indicates rapid growth of immature blood cells which occupy so much space that bone marrow is not able to produce new, healthy blood cells. If immediate treatment is not sought for ALL in children, the result is more than often death in a few months or even weeks (National Cancer Institute 2002).

Factors that May Cause Reduced Ankle Dorsiflexion in Childhood Leukemia

It has been proven that survivors of childhood ALL have reduced ankle movements when compared to healthy children. Reduced ankle dorsiflexion is a prevalent problem in childhood leukemia in which dorsiflexion (upward movement of the ankle) is damaged and has a limited range of motion. These victims can only move their ankles less than five degrees up and down. A person with healthy ankles should be able to move their ankles at least twenty degrees up and thirty-five degrees down to be able to perform all daily activities (Wright et al. 1999).

Chemotherapy, the most common treatment for childhood leukemia, is the introduction of cytotoxic (anti-cancer) drugs into the body to attack cancer cells. These drugs are generally delivered via the bloodstream so that they can reach cancer cells in any part of the body. The drugs will attack cancer cells by inhibiting their growth cycle or keeping them from dividing. Although this is a widely used treatment for ALL, and many other types of cancer, it does have many side effects that can lead to reduced ankle dorsiflexion (Cancerbackup 2006).

One of the most common side effects of chemotherapy in ALL patients is thrombocytopenia (decreased platelet count). Platelets are present in the blood to help clot blood when someone gets a wound, a decrease in the amount of platelets results in increased bleeding and bruising. When this happens in children, their parents are often hesitant to let their children play sports or even go to the park. When the child stays in bed or is sitting at home, their dorsiflexor and plantar flexor motions (downward motion of the ankle) are not being utilized (Anon 2006).

Another common side effect of chemotherapy is fatigue. This fatigue can be caused by anemia (reduction of red blood cells, which is another side effect of chemotherapy) or chemotherapy itself. Regardless, fatigue in children isn’t healthy because this tiredness is another factor that causes them to stay in bed or in a constant sitting position (Anon 2006).

Cardiotoxicity is also a side effect of chemotherapy. This occurs when the heart muscle is damaged and doesn’t pump enough blood throughout the body. Blood especially has trouble reaching the extremities and can make it difficult for a child to have enough energy to want to exercise that part of the body (Cancerbackup 2006).

When lack of physical activity occurs by decreased platelet count, fatigue, cardiotoxicity or for any other reason, it is a problem. Leaving the muscles in one position for too long can cause muscle atrophy. Atrophy is the loss of muscles tissue due to lack of use. When someone is not regularly physically active, their muscles literally shorten to an appropriate length for everyday use. This is what causes reduced ankle dorsiflexion. The muscles’ shortening restricts dorsiflexor and plantar flexor ankle movements and therefore causes reduced ankle dorsiflexion (Medline Plus 2005).

Common Physical Activities that may be Affected by Reduced Ankle Dorsiflexion

Since reduced ankle dorsiflexion can damage your ankle movement to only five degrees up and five degrees down, many daily physical activities are affected. Reduced ankle dorsiflexion also affects the calf muscles, which are responsible for jumping and sit and reach flexibility. Children with reduced ankle dorsiflexion will not be able to play volleyball. This has been proven through a study of patellar tendon health, which is affected by damaged dorsiflexion motion (Mallarias et al. 2006). This will also affect playing basketball, tennis, soccer, and many other sports that require a great amount of physical strain. Almost all activities will be limited by reduced ankle dorsiflexion because walking and stair-climbing are severely altered due to limitations on ankle movement (Wright et al. 1999).

Device to Practice Ankle Exercises to Prevent Reduced Ankle Dorsiflexion

To prevent reduced ankle dorsiflexion, appropriate exercise must take place everyday. The idea of a bouncing ramp has been proposed for a four year old victim to exercise on while she brushes her teeth. There is a current design out on the market called Prostretch, but this doesn’t have enough resistance to help increase ankle range of motion. This ramp is invalid due to the fact that it doesn’t exercise the full range of ankle motion. Although this ramp has a good active component when the patient bounces forward, the passive component of the ramp isn’t sufficient to exercise her because she is simply leaning back on her heals rather than plantar flexing (Kuzma 2005).

To create a device that sufficiently exercises the appropriate muscles, both active and passive components of muscles need to be considered (Herzog 2003). Dorsiflexion and plantar flexion need to be stretched to their full capacity with the appropriate resistance to this motion as well. To effectively do this, a special bicycle-like device has been proposed. This device will have pedals that are attached to gears that rotate with an adjustable resistance. This device does not have any wheels, however it must have a seat and handle bars.

Pedals: This device’s pedals are specially designed so that the patient cannot rotate them in a full circle unless she is pedaling at the proper angle. When she pedals down, the pedals will have resistance until she angles her ankle downwards exactly twenty degrees to practice plantar flexion. When she pedals back up, the pedals will have resistance until her ankle pushes upwards exactly thirty-five degrees to practice dorsiflexion. The patient’s feet will be strapped onto the pedals to ensure proper movement along with the pedal angles.

Resistance: The resistance of these gears can be adjusted by the patient’s parents according to her weight and strength. Resistance adjusts simply just like the hand gears on a bicycle.

Seat: The seat will be raised higher than a normal bicycle so that the patient can keep her legs almost straight. This is because on a normal bicycle, one exercises their thigh muscles, but by increasing the height of the seat, the patient will be forced to pedal with her ankle motion rather than her full leg motion.

Balance: The handle bars are for balance because this device is meant for young children. This device can be mounted into the ground to provide further stability. This is so that the patient will not fall off of the device if she fools around.

Entertainment: Due to the balance of the device, the patient can watch television while exercising. There will also be a display screen in the middle of the handle bars with the alphabet running across it. This screen will also indicate the number of calories burned and how long the patient has been exercising for.

This device will sufficiently exercise the passive and active components of dorsiflexion and plantar flexion.

To measure the whether or not the amount of exercise is successful on dorsiflexion and plantar flexion, a device called chatillon dynamometer is available. This device can be used anywhere at anytime. The patient’s foot must simply be placed flat on the ground. Someone then needs to hold the device directly below her toe line and instruct her to raise her foot with her heal remaining on the ground. The chatillon dynamometer then measures the resistance of the foot to the machine and calculates the force exerted by the foot. This machine can also measure plantar flexion motion (Anon 2005).

Even if the patient uses this device everyday, there are also other factors that need to be considered to keep her healthy. She needs to keep a well-balanced diet because children on chemotherapy often have fluctuating weight and poor nutrition. This is because chemotherapy alters the metabolism of nutrients so that fats, carbohydrates, and proteins are metabolized too quickly (Picton 1998). To avoid depression, children are encouraged to play outside and visit friends daily. Chemotherapeutic drugs often cause depression and physical activities raise the levels of serotonin in the body to keep people happy and healthy (Anon 2006). The most important thing that a patient can do to avoid reduced ankle dorsiflexion is to stretch and jog. Studies have shown that less than fifteen minutes of stretching a day can increase dorsiflexion range of motion (Radford 2006). Overall, this young patient can live a normal life with the proper combination of chemotherapy, exercise, diet and emotional support.

-Amy Shah