A Guide To Orthotic Therapy For Adult-Acquired Flatfoot
- Volume 24 - Issue 7 - July 2011
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An orthotic laboratory makes a Root-type footplate that has two stirrups with leg uprights attached, producing the lower leg component. The hinges between the stirrups and the uprights allow sagittal plane motion during gait but inhibit frontal and transverse plane motion. The concept is to provide external fixation between the rearfoot and the lower leg to compensate for the damaged and attenuated ligaments.3
Custom-articulated AFOs, in my experience and in a case report, produce greater anatomic alignment than prefabricated or non-articulated AFOs.12 However, it is merely an assumption that anatomic realignment actually delays further deformity or produces any permanent correction. We do know that anatomic realignment, especially of the rearfoot, reduces symptoms.
Selecting footwear for the stage II patient is as important as selecting the brace. Again, in my experience, patient adherence in treatment is primarily a function of orthotic comfort and the ability to wear culturally acceptable footwear. Rigid athletic shoes with motion control or shoes with stiff shank construction and reinforced heel counters are essential. Occasionally, persistent edema in a patient with this pathology will necessitate extra depth shoes.
Recommendations On Pathology-Specific Orthoses For Stage II AAF
Negative cast: podiatric AFO fabricated from a neutral cast with the supinatus reduced
Positive cast correction: perpendicular
Material: deep heel cup of 25 to 35 mm
Width: wide with medial flange
Cast fill: standard to maximum dependent on deformity
Heel skive: 6 mm
Hinges: full flexion hinges with bilateral lower leg uprights
Positive cast modification: navicular sweet spot
Rearfoot post: flat or 0/0
Top cover: full-length top cover
What You Should Know About Treating Stage III AAF
The challenges in treating stage III AAF with an orthosis are due to the reality of the foot being deformed and rigid, with seemingly intractable symptoms of pain in the medial arch.3,4 Non-surgical treatment will not reverse or improve the deformity. Treatment goals are limited to reducing symptoms and preventing greater subluxation while attempting to keep the patient ambulatory. These goals also focus primarily on immobilization that allows ambulation.
It is therefore the goal of treatment to restrict motion in all three rearfoot joints while keeping the patient ambulatory. Restricting the subtalar joint while allowing ankle and midtarsal motion does little to relieve symptoms.10 Conversely, clinical experience suggests that controlling sagittal plane motion at the ankle but disregarding midtarsal joint motion only produces greater arthritic degeneration as the midtarsal joint dorsiflexes to compensate for the loss of the ankle sagittal plane motion. This is a plane of motion unsuited for the unstable midtarsal joint.
The gauntlet type of AFO, which combines a custom polypropylene shell interior wrapped in a lace-up leather exterior envelope, allows restriction of motion of all three joints in all three planes without sacrificing the patient’s ability to ambulate and wear reasonable shoes. These braces are individually fabricated on a positive corrected mold of the patient’s foot from a semi-weightbearing cast with the foot at right angles to the leg in the sagittal plane.
Although this brace has been available for more than a decade, few podiatrists or orthopedic surgeons embraced this therapy until the research of Imhauser and colleagues in 2002 demonstrated that, in comparison to other modalities, the gauntlet “completely restored the height of the arch and height of the navicular.”12