A Guide To Orthotic Therapy For Adult-Acquired Flatfoot

Author(s): 
Paul R. Scherer, DPM

   Conversely, treating the early stages using the therapies for the advanced subluxations is probably unpredictable and unsuccessful as well. Using advanced surgical procedures and highly restrictive orthoses and braces on early stages may well produce the unwanted outcomes of muscle atrophy and additional symptoms. Each stage should have its own treatment protocol that matches the requirements of its specific pathomechanics.

   Although several authors attribute adult-acquired flatfoot to seropositive or seronegative arthropathies, in the overwhelming majority of cases, adult-acquired flatfoot is solely a local lower extremity phenomenon.4-6 Any valid classification should focus on this as well as the contributing factors, such as obesity and gender, that seem to determine both severity and accelerated progression of deformity.

   Clinicians should consider a “pre-stage” to the disease, consisting of the acute onset of symptoms, characterized by pain, swelling, tendinitis and disability along the course of the tibialis posterior.3 One must treat these symptoms immediately with immobilization, compression, elevation and ice or nonsteroidal anti-inflammatory (NSAID) medications. Reduction of the initial acute symptoms will allow a more thorough examination to help determine the extent of the damage and the appropriate staging of the disease to produce a more focused and specific treatment plan.

Emerging Diagnostic Insights

Proper and effective therapy requires periodic assessment and staging of the continuing progression of deformity and pathology. I believe it is essential to have accurate examination by weightbearing radiograph, recording accurate rearfoot eversion relative to the ground and assessing muscle strength and symmetry relative to the opposite foot. Muscle testing should include weightbearing assessment since the non-weightbearing tibialis anterior’s strength can mislead the examiner into thinking that the tibialis posterior is stronger than it is.

   Observation of the change in morphology of the weightbearing foot during a simple heel raise, rather than simply a positive or negative response to this test, is invaluable. Many patients cannot perform the heel raise test but this does not mean they have adult-acquired flatfoot. The total collapse of the arch and dorsiflexion of the forefoot on the rearfoot as the heel lifts on the weightbearing foot are good indications of the progression and worsening of adult-acquired flatfoot.

   Most clinicians realize the significance of performing the first metatarsal rise test, which was first described by Hintermann and co-workers, and the supination lag test, discussed by Abboud and colleagues, as assessments rather than mere diagnostic tests.7,8

   Hintermann and colleagues observed that radiographs and MRIs were unreliable when it came to diagnosing dysfunction of the tibialis posterior tendon.7 They designed the first metatarsal rise sign to help recognize and treat adult-acquired flatfoot at an early stage when the foot is still supple. Patients perform the test standing with equal weight on both feet. When the leg is passively and externally rotated, the first metatarsal head immediately rises off the ground in a patient with a dysfunctional tibialis tendon while it remains on the ground in a normal patient. Hintermann and co-workers compared the use of this test in 21 patients and found that it was always positive whereas the “too many toes” sign and single heel raise were positive in approximately 80 percent of the patients.

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