Gait Analysis In Pediatric Patients With Flatfoot
The F foot is the classic pes planovalgus foot type. It is the combination of a compensated rearfoot (like the D type) coupled with a forefoot varus/supinatus. The name of the game in gait is that we will attempt to load the medial column at all costs no matter how the foot hits the floor. At foot flat, the heel has already everted to vertical (compensated rearfoot), unlocking the midtarsal joint. In this case, however, pronation continues through midstance and into propulsion as further pronation is required to compensate for the forefoot varus. Pronation will continue until the medial column loads. Accordingly, this foot type typically remains unlocked throughout the stance phase and into propulsion.
The abducted forefoot (abductory twist), as a result of the forefoot varus/supinatus, lends to the severity of this “deformity.” The resultant posterior tibial tendon dysfunction often necessitates surgical procedures such as triple arthrodesis and ankle fusions. Conditions in this foot may be similar to those of the D quad but may also include tarsal tunnel syndrome, subfibular impingement and neuromas. The progression angle of gait often appears “toe out” but that is often an illusion. Limb alignment from the hip is often neutral to mild toe out but the forefoot abduction creates an illusion of a larger toe out gait (abductory twist).
Getting A Clearer Clinical Picture Of The Pediatric Patient
Now that we have reviewed the two major flatfoot types, let us talk about how we can incorporate this information into our age-specific analysis of the typical flatfooted podopediatric patient.
One of the first questions I ask my pediatric patients (and their parents) is “What sports do you like to play?” Not playing sports or a lack of enjoyment of sports/physical activity is a red flag. Have the patients always been inactive? Is it because they are slower than or not as coordinated as their peers? Are they self-conscious because of how they run or how poorly they compete? I feel a lot of choices these children make regarding athletics and other physical activities are a direct result of their underlying foot types. You will be surprised. Take the time to talk to your pediatric patients about the things they like to do (or do not like to do). You will start to see patterns.
There have been a few studies indicating an abnormally high percentage of flatfooted children who are overweight, showing a correlation between arch height and childhood obesity.1-3 I personally do not believe that obesity in children causes flat feet but the other way around. Naturally occurring hypermobile flat feet result in instability, poor trunk strength and stability, and a resultant sedentary lifestyle.
There are several things to consider when treating biomechanical issues of the foot, regardless of the patient’s age. First, we need to understand the normal ranges of rearfoot and forefoot varus/valgus from infancy through adulthood. Forefoot varus is traditionally not something we treat until children are at least 6 to 7 years of age. It is necessary to allow the forefoot to derotate and encourage a proper inclination angle of the first ray so one does not typically use extrinsic forefoot posting at this young age.
Identification of a significant forefoot varus in young children is important. However, we are not necessarily treating it but just monitoring the condition. The general rule of forefoot varus is that the child loses about 2 degrees of forefoot varus every year up until about the age of 6. At birth, if you were able to measure it, 12 to 15 degrees of forefoot varus is average with derotation of the varus ideally completed by the age of 6 or 7. Compensation for a forefoot varus requires calcaneal eversion beyond vertical. Forefoot varus conditions are very destructive at an early age and result in severe hyperpronation. Any residual forefoot varus after the age of 7 or 8 may need specific orthotic correction/posting, either intrinsic or extrinsic.