Video Consultation with Cindy Diener, CPO

In this issue we are featuring a video analysis of a 5 year old girl who was born prematurely and has been diagnosed with cerebral palsy. She is currently receiving physical therapy, with concerns centering on her balance problems and severe pronation of both feet. When weight bearing, her feet collapse into pronation (hindfoot everting into valgus, midfoot collapse and forefoot abduction). Her navicular becomes very prominent when she stands, leading to concerns about possible skin breakdown. Her hindfoot, forefoot and knee range is within normal limits, while her dorsiflexion range is a little restricted. She does have strength limitations in her hips, which has led to an excessive amount of external rotation during static standing and ambulation. The therapist’s main goals are to correct the severe pronation in order to improve the patient’s overall balance. Secondarily, the therapist would like the braces to help with the excessive external rotation if possible.

Observation of Gait - Without Braces

This patient’s gait is particularly unusual because of the excessive external rotation she exhibits. In this case, the patient fixes into the rotated position for stability due to weakness of the obturators and piraformis muscles in the hip region. This results in a significant swivel movement of the hips during ambulation. Her balance is very poor and she tends to fall frequently during ambulation. Hence, she walks with her arms in a high guard position. She exhibits severe pronation bilaterally. Her navicular is very prominent and tends to be in contact with the floor during portions of her gait cycle, particularly from mid stance to push off. She does have some active dorsiflexion which is seen during swing phase.

Observation of Gait - With Braces

The patient was observed in the video wearing DAFO 4 braces bilaterally. My first concern is that the DAFO 4 braces do not offer enough support to control the severe pronation the patient exhibits. Observation of the patient during stance shows the lateral side of her lower leg in contact with the lateral ‘ear’ of the braces. Her therapist has also reported navicular ‘red spots’ on both feet. Both of these indicate on-going pronation. Further examination of the video revealed that the patient is pronating inside the brace shells, not just overpowering the braces. Generally, this is an indication that the brace shell is too loose. The fit between the patient’s foot and the shell needs to be very close for the brace to adequately control severe pronation. If the brace shell distorts as the foot pronates, this usually indicates that the fit is sufficient, but 1) the brace materials or features need to be optimized to resist the force of the pronation, or 2) a brace style with a higher level of pronation control is required.

As expected, the braces have not reduced or modified the patient’s hip-related external rotation.

Recommendations

I am recommending a change to bilateral DAFO 3.5 braces. The proximal upright of the DAFO 3.5 is much taller than the DAFO 4, adding significantly more medial-lateral leverage for stabilizing the heel valgus that occurs with severe pronation. As this flexible proximal section is normally used for modulating ankle dorsiflexion-plantarflexion (something this patient does not have a significant problem with), I would recommend that the proximal upright be set at ‘very flexible’ on the order form to minimize interference with ankle function.

The brace’s ability to control foot position, particularly for severe pronation, is dependent on a close, intimate fit with the patient’s foot. The key to getting a good fit is to start with a very precise cast of the patient’s hindfoot, forefoot and ankle, captured as close to the corrected alignments as possible. The cast (and the brace) should be at least to the apex of the gastrocnemius muscle to get the leverage required to control the pronation.

I would highly recommend casting this child in a varus forefoot alignment. This forefoot varus post will change a number of things to improve comfort as well as impact her overall alignment. The intentional elevating of the forefoot into varus on the medial side (approximately 1/8” - 3/16” in this case) will help prevent her midfoot from collapsing and the hindfoot from everting into the unstable valgus position. With the forefoot posted, the navicular becomes less prominent and nearly undetectable within the soft tissue, thus helping to eliminate pressure over the prominence.

This varus forefoot posting may also help with the excessive external rotation. Although lower extremity bracing usually has little to no affect on the correction of torsion related in-toeing or out-toeing, posting of the forefoot can sometimes help with hip-related excessive external rotation (as in this case with the patient having normal range). Posting the forefoot in varus can “encourage” the patient to bring the foot from its turned-out, externally rotated position into a more normal (less rotated) alignment.

Conversely, if there is too much hip-related internal rotation (toes pointed inward), posting the forefoot in a valgus position would encourage less in-toeing. I am very optimistic that the posting will improve the overall foot position resulting from the external rotation coming from the hips.

To further optimize the brace for maximum pronation control, I would recommend requesting “ST” support (better known as sustentaculum tali) to control the hindfoot. ST support gives a pre-relief area to the navicular and helps stabilize the hindfoot. I would add PPT padding to the navicular (a check box on the order form). This is a very resilient padding that does not bottom out over time.

With these optimizing features and a properly fitting brace, the patient should experience better balance from a properly aligned foot and a decrease in the external rotation of her hips.