Abstract
Pronation of the foot is an essential motion of the normal function of the lower extremity. Its main contribution to the gait cycle is shock absorption and adaptation of the weight bearing foot to the surface. Hyperpronation is defined when hind foot motion is excessive, prolonged, and/or occurs in inappropriate timing of the stance phase. Hyperpronation of the foot may cause malalignment of the lower extremity and frequently leads to injuries to joints, tendons, knee pain and stress fractures. A review of the literature indicates that a correlation is found between hyperpronation of the foot and tibial rotation, patella and knww joint alignment. To our knowledge there is no evidence documented on the relationship between hyperpronation and pelvic alignment although, several researchers do suggest a possible connection. The purpose of this study is to examine the effect of hyperpronation of the feet on the lower limb and pelvic alignment.
Thirty-five healthy subjects (15 men and 20 women, age ranged from 23 to 33 years) were put into hyperpronation in standing position induced by wedges of different slopes of 10, 15 and 20 degrees. The base line for comparison was natural standing position and the sequence of trials was random. Each setting was maintained for 20 seconds and a sample of 4 seconds was processed and measured. Changes in the alignment of the lower extremity and pelvic were measured by a computerized system of motion analysis (VICON®).
Standing on the wedges induced hyperpronation with statistically significant increase in calcaneal eversion (p< .000). The results indicated that as a consequence to the usage of wedging on limb alignment, a statistically significant increase (paired t-test) in calcaneal valgus (p< .000), internal tibial rotation (p< .000), internal femoral rotation (p< .000) nd anterior pelvic tilt (p< .000) was found. A strong correlation (Pearson correlation coefficient) was found between segmental alignments in every two sequences positions (r = .612 up to .985). Five sets of mixed effects models for repeated measurement were built in all four positions. Results showed that the effect of the tibial alignment itself is responsible for the change in the pelvic position (p=.002).
These findings suggest that a correlation exists between motion at the distal segment (the foot) and the proximal segment (the pelvic) aof the body and indicate that hyperpronation and proximal postural malalignment are linked. This interaction between the foot and pelvic occurs in a chain reaction manner. Foot hyperpronation can influence pelvic alignment, only if significant change arises at the tibia.
The implication of this study advocates that when addressing pelvic and lower back dysfunction, the alignment of the foot should be examined as a contributing factor.
In addition, addressing foot malalignment is essential for treating and preventing pelvic and low back dysfunction.
The abstracts were prepared by Ms Orah Naor. Correspondence should be addressed to Israel Orthopaedic Association at PO Box 7845, Haifa 31074, Israel.
