One should neutralize pathomechanical forces acting on the child’s foot from the earliest weightbearing in order to allow normal development of bone and soft tissue without undue stress and establish optimum foot function in stance and gait. The functional requirement of a stable platform once the child has begun to stand and for the stance phase of gait is compromised in the flat foot. Later, once the child has achieved propulsive gait, the ability of the foot to convert to a rigid lever is also altered in the flat foot.
A careful musculoskeletal exam including gait analysis will allow the clinician to build on information obtained in the history to identify the superstructural and pedal comorbidities that lead to compensation in the already challenged toddler foot. Experts agree that a positive family history of a consequential flat foot, evidence of a compensated, acquired flatfoot through skilled biomechanical evaluation and compromised gait function all elevate the index of suspicion in a pediatric flat foot and strongly suggest that one should consider treatment.
The presence of comorbidities in the biomechanical exam in the form of deviations from the normal for the child’s age marks these feet as “at risk” and provide a clear rationale for the astute clinician to act and to intervene on the child’s behalf. Unless and until these comorbidities resolve and cease to exert an untoward effect on the malleable foot compensating at the base of support, the physician should institute treatment.
Common comorbidities contributing to pediatric acquired pes planovalgus include residual transverse plane torsional problems such as femoral and tibial torsion and metatarsus adductus. Soft tissue components such as excessive internal hip rotation and pseudo torsion at the knee may also lead to pedal compensation. Frontal plane malalignments such as rearfoot and forefoot varus, tibial and genu varum may precipitate compensation. Sagittal plane contributions include equinus and limitations of dorsiflexion necessary for smooth excursion of the leg over the planted foot in gait. These may occur at the level of the foot, the gastroc-soleus complex, the hamstring and the iliopsoas muscles.
Numerous joints in the foot with sagittal plane dominance — such as the midtarsal joint, first ray and metatarsophalangeal joints — facilitate compensation and may lead to acquired deformities of the foot.
Systemic ligamentous laxity, as a component of a syndrome such as Marfan’s syndrome or as a familial or individual body type predisposes the child’s foot to be the compensatory site for superstructural influences.