The relationship between forefoot, midfoot, and rearfoot static alignment in pain-free individuals

Correlational study.

To determine whether, and to what degree, a relationship exists between forefoot angle and weight-bearing midfoot and rearfoot position.

There have been conflicting reports with regard to the degree to which the structure of the foot may influence the function. The influence of forefoot structure on weight-bearing midfoot and rearfoot position has not been extensively investigated.

Fifty-one healthy subjects participated in this study (26 male and 25 female). Forefoot angle was measured in prone as varus (positive numbers), neutral (0), or valgus (negative numbers). Navicular drop was measured from subtalar joint neutral to unilateral standing relaxed. Rearfoot angle was measured in relaxed single-limb stance as the angle between a line that bisected the calcaneus and a line that bisected the lower third of the leg. The relationships between forefoot angle and navicular drop, and between forefoot angle and relaxed rearfoot angle, were investigated. The same relationships were also investigated in the neutral forefoot subgroup when the sample was divided in 3 subgroups based on 1 standard deviation of forefoot angle.

There is a significant relationship between forefoot angle and relaxed rearfoot angle (r = 0.52, P < .001), as well as between forefoot angle and navicular drop (r = 0.55, P < .001), in the whole sample (n = 51). Average degrees of forefoot angle in the neutral subgroup (between 1.0 degree and 8 degrees of varus) are not associated with predictable positions of relaxed rearfoot angle (r = 0.19, P = .24) or navicular drop (r = 0.01, P = .96).

Based on the results of this study, there is a significant relationship between forefoot angle and relaxed rearfoot angle, as well as between forefoot angle and navicular drop, in healthy subjects. These relationships were not found when forefoot varus values were within a standard deviation of the sample mean.