Feet: you either love them or hate them. However, whatever your personal feelings toward them, they play an integral role in our posture throughout our bodies. Simply put, the foot is the foundation of standing posture.
According to current research, changes in the alignment of the foot bones, specifically the talus and calcaneus, may lead to postural alterations and structural abnormalities due to compensatory postural strategies.1 Pelvic alignment is the key to postural alignment to the body located superiorly to the pelvis, as it acts as an intermediary between the lower extremity and the spine. Eversion of the calcaneal bone has led to significant changes in pelvic alignment.2
The key joint that has the largest impact on posture is the subtalar joint. The calcaneus’s superior articulation with the talus forms the subtalar joint. Normally the talus is positioned directly above the calcaneus. However, as this joint is a plane/ gliding joint, there is not much ligamentous stability between the two bones.3 This results in the calcaneus shifting medially or laterally under the talus.
Pronation, or eversion, of the calcaneus occurs when the calcaneus shifts laterally as compared to the talus. Pronation of the calcaneus causes the talus to move anterior and medially, dropping the medial longitudinal arch. The shifting of the talus also induces internal rotation of the tibia.3 Internal rotation of the tibia in turn leads to internal rotation of the femur.3
If this occurs bilaterally, the person will appear to have genu valgum. Internal rotation of the femur causes the head of the femur to place pressure on the posterior aspect of acetabulum, leading to anterior rotation of the os coxa.1 This side of the pelvis will also be lower compared to the other side of the pelvis. Leg-length inequality may also be seen, with the affected foot appearing to be shorter than the non-affected leg.
Methods
Ten healthy subjects with an age range of 20-23 years participated in a study in which their feet, knees, hips, and pelvis were adjusted using the Gravitational Pattern Alignment protocol to properly align the foot bones and pelvis. The patient stood barefoot on level ground, while an electronic level was attached to their right iliac crest using a gait belt. An initial reading was taken.
A 10 mm heel lift was placed halfway under the lateral side of the foot to induce pronation of the foot. An angle of change reading was taken from the electronic level. The heel lift was removed, and the process was repeated two more times.
Results
The largest change was 2.05 degrees, while the lowest change was 0.2 degrees. The average change angle for pronation was -0.63625 degrees, with a significant P value of 0.05. These changes showed an anterior rotation of the os coxa.
Conclusion
The significant P value indicates that there is a positive collocation between pronation of the foot and anterior rotation of the os coxa. Pronation of the foot induces significant anterior rotation of the os coxa. When assessing anterior rotation of the os coxa, this study indicates that you must also check for pronation of the foot. Further research will need to be completed to see if returning a foot to neutral posture can also return the os coxa to neutral posture.
References
- Ghasemi MS, et al. The effect of hyper pronation on spine alignment in standing position. Med J Islam Republic Iran, 2016 Dec 28;30:466.
- Pinto RZ, et al. Bilateral and unilateral increase in calcaneal eversion affect pelvic alignment in standing position. Manual Ther, 2008 Dec;13(6):513-519.
- Khamis S, Yizhar Z. Effect of feet hyper pronation on pelvic alignment in standing position. Gait and Posture, 2007 Jan;25(1):127-134.
