Patient Presentation | Excessive Plantarflexion

In our Winter 2006 Newsletter we introduced our approach for working with how patients present and some guidelines for selecting the most appropriate brace. We will be covering each of the seven patient presentation groups in our newsletter, one at a time.

The traditional approach to brace selection at Cascade has been to assess each patient’s presentation from the bottom up, looking first at the biomechanical needs of the foot, then the ankle, and finally the knee as applicable. The final step of choosing a brace, however, has often been difficult for those less familiar with the names and features of our brace designs.

To help assist in the brace selection process, we began to organize patient presentations into groups based on the foot, ankle and knee presentations we most often see in our patient population. Within each group we defined the range of involvement, matching each of these presentations to an appropriate brace design. Directly associating a brace design/bracing strategy with a defined patient presentation has worked well, both in theory and in practice.

We have used our grouping system with the understanding that while not perfect, it is a reasonable (and clinician friendly) way of approaching the brace selection process. In this issue we will look at Excessive Plantarflexion, or Toe Walking.

Excessive Plantarflexion – Toe Walking

During the development of standing and walking skills, children will often bear weight on the forefoot without bringing their heels consistently down to the ground. This is commonly referred to as “toe walking” and is a normal part of a toddler’s progress toward normal standing and walking. By about age three, children will begin to bring their heels down and to bear weight along the full length of their feet. Their gait will develop into the standard heel-toe pattern of the normal gait cycle.

If toe walking continues beyond age three, if the elevation of the heel off the ground is extreme, or if the child is not able to bring his heels down to the ground due to tightness in the muscles or tendons, a neurological problem may be indicated. A complete medical evaluation should be performed to establish the true etiology of the condition.

Neurological problems can cause chronic or periodic contractures of the calf muscles (gastrocnemius m.and soleus m.) or chronic contractures of the Achilles tendon. These contractures will pull on the heel, rotating the foot via the ankle into an excessively plantarflexed position. The condition can be unilateral, bilateral, or asymmetrical (both sides affected, one side more than the other), as this is the result of hypertonia. The foot tone likewise tends to be high and will require evaluation for overall flexibility and correction to achieve an improved position.

Mild Toe Walking

In the mildest form of toe walking, the patient will usually have a balanced foot alignment, will have good ankle range (including near normal dorsiflexion), and will stand with the foot flat, bearing weight equally along the entire foot. When walking is initiated, the stimulation of over-active calf muscles pulls the foot into a slightly more plantarflexed position than normal. This results in a delay of heel strike during the gait cycle. When walking stops, the muscles relax and weight is borne equally along the entire foot.

The bracing strategy consists of 1) correcting foot position as required, 2) limiting plantarflexion while encouraging dorsiflexion to improve heel strike during gait and 3) maintaining ankle range. A DAFO 4 with a posterior strap would be suitable for the smaller patient, particularly during the transition phase of floor-to-stand activities. For the larger patient, a DAFO 3 provides a stronger plantarflexion block while still allowing free dorsiflexion. Both braces provide a full dorsal wrap for optimal foot control.

Mild-to-Moderate Toe Walking

In the mild-to-moderate form of toe walking, spastic contractures may be chronic and/or moderately strong. Foot alignment may be affected by mild to moderate high tone pronation or supination. Ankle range may be limited, but can still be corrected close to 90º. When gait is initiated (no brace), the patient’s foot is pulled into plantarflexion and does not make initial floor contact with the heel, but instead makes contact along the entire foot directly to foot flat.

The bracing strategy for this mild-moderate level includes 1) correcting foot position as required, 2) blocking or strongly resisting plantarflexion and encouraging dorsiflexion to improve heel strike during gait and 3) maintaining ankle range. Brace ankle position should be set at 3 to 4 degrees dorsiflexion whenever possible. The plantarflexion resist offered by a DAFO 3.5 brace may be suitable, provided the accompanying dorsiflexion resist allows suitable mobility. The plantarflexion block offered by a DAFO 2 or DAFO 3 is suitable when free dorsiflexion is required. Factors influencing choice will be level of muscle tone, ankle range, patient size and desired medial-lateral control. Maintenance of ankle range increases in importance, particularly as range diminishes.

Moderate-to-Severe Toe Walking

In the moderate-to-severe form of toe walking, spastic contractures are chronic and relatively strong. Foot alignment may be affected by high tone pronation or supination. Ankle range may be limited, but can still be corrected close to 90º. When gait is initiated (no brace), the patient’s foot is pulled into plantarflexion and makes floor contact with the forefoot only (toe walking).

As the level of high tone plantarflexion increases, seating the heel down into the brace will become more difficult. Pressure along the instep strap will be very high, often to the point of discomfort. The full plantarflexion block of DAFO 2 or DAFO 3 is required to counter strong plantarflexion contractures. Brace ankle position should be set at 3-4º dorsiflexion whenever possible. For the highest levels of tone, the maximum control qualities of the DAFO Turbo two-part brace may be required.

As contractures of the gastrocnemius m. and/or Achilles tendon increase in strength and degree, there is a higher likelihood that additional therapies will be necessary to get enough ankle range to make brace use feasible. These would include: 1) serial casting with Botox; 2) an active stretching program and night positioning brace; and 3) heel cord surgery.

If these are not available, additional bottom stabilization in the raised region (heel wedge) to support the patient’s weight can be beneficial. This is only feasible up to about one inch of heel height, depending on the size of the patient, as the brace becomes difficult to fit in a shoe.