Forefoot Valgus- The Plantarflexed First Ray
The following chart is designed to clarify the various differences in forefoot valgus and plantarflexed first ray deformities. This illustrates the need for detailed information to properly evaluate and post these deformities.
* Note 1: A relationship which is not totally rigid or flexible may be termed semi-rigid or semi-flexible depending on the examiner’s inclination. This means that there will be a need to interpolate when applying orthotic therapy. This interpolation will be applied mainly by varying the degrees of posting. Therefore, it is important to remember that an increase of decrease in the plantarflectory force that the peroneus longus muscle exerts on the first ray is directly proportional to a corresponding increase in the rearfoot varus posting.
* Note 2: The amount of forefoot valgus or rearfoot varus posting is determined by the anatomical relationship of the forefoot to rearfoot. Therefore, when posting, we do not arithmetically add or subtract one from the other.
* Note 3: Subtalar joint pronation is a prime shock absorbing mechanism in the foot and leg. It is largely absent in rigid type feet. As a consequence, heel spur pain in the rigid foot is generally due to acute impact and shock against a taut plantar fascia. This is typically the type of shock received during sports activities.
Therapeutically, this foot requires additional shock absorption through materials added to the orthotic devices. On the other hand, heel spur pain in the flexible foot is generally due to chronic pulling of the plantar fascia at its insertion into the periosteum covering the medial weight bearing tubercle of the calcaneus. This results in subperiosteal bleeding, leading to heel spur formation and requires reduction of the proximal to distal elongation of the foot through orthotic control.
Table: Variations in Forefoot Valgus and Plantarflexed First Ray Deformities