Effect of foot orthoses on magnitude and timing of rearfoot and tibial motions, ground reaction force and knee moment during running.

Changes in magnitude and timing of rearfoot eversion and tibial internal rotation by foot orthoses and their contributions to vertical ground reaction force and knee joint moments are not well understood. The objectives of this study were to test if orthoses modify the magnitude and time to peak rearfoot eversion, tibial internal rotation, active ground reaction force and knee adduction moment and determine if rearfoot eversion, tibial internal rotation magnitudes are correlated to peak active ground reaction force and knee adduction moment during the first 60% stance phase of running. Eleven healthy men ran at 170 steps per minute in shod and with foot orthoses conditions. Video and force-plate data were collected simultaneously to calculate foot joint angular displacement, ground reaction forces and knee adduction moments. Results showed that wearing semi-rigid foot orthoses significantly reduced rearfoot eversion 40% (4.1 degrees ; p=0.001) and peak active ground reaction force 6% (0.96N/kg; p=0.008). No significant time differences occurred among the peak rearfoot eversion, tibial internal rotation and peak active ground reaction force in both conditions. A positive and significant correlation was observed between peak knee adduction moment and the magnitude of rearfoot eversion during shod (r=0.59; p=0.04) and shod/orthoses running (r=0.65; p=0.02). In conclusion, foot orthoses could reduce rearfoot eversion so that this can be associated with a reduction of knee adduction moment during the first 60% stance phase of running. Finding implies that modifying rearfoot and tibial motions during running could not be related to a reduction of the ground reaction force.

Acute effect of orthoses on foot orientation and perceived comfort in individuals with pes cavus during standing.

BACKGROUND: Changes in foot orientation due to orthoses and the relationship with perceived comfort are still unclear in pes cavus. The purpose of this study was to determine the acute changes of fore-foot angles due to the use of custom-made orthoses and their relationship with perceived comfort during standing. METHODS: Two photographs were taken using a color-coded camera-based system from the posterior and medial views of 20 subjects with bilateral pes cavus under barefoot and with orthoses conditions during standing. Djian-Annonier, calcaneal inclination, 1st metatarsal declination and rearfoot angles were measured and perceived comfort in the forefoot, midfoot and rearfoot was estimated using an adapted Visual Analogue Scale-type questionnaire. RESULTS: In comparison with the barefoot condition, orthoses increased significantly the 1st metatarsal declination angle by 1.9 degrees (p<0.01), and the Djian-Annonier angle by 1.1 degrees (p=0.02). The calcaneal inclination angle decreased significantly by an average of 3.0 degrees (p<0.01). Wearing orthoses significantly improved perceived comfort in forefoot, midfoot and rearfoot when compared to barefoot condition (p<0.01). A significant correlation was observed between variation of calcaneal inclination angle and the perceived comfort at the midfoot (r=-0.44; p=0.04). CONCLUSION: Flattening of foot arch and improvement of midfoot perceived comfort in pes cavus could be attributed to the reduction of the calcaneal inclination angle in the sagittal plane by using orthoses during standing.

Reliability of a computer-aided color-coded video-based system for clinical assessment of the foot.

UNLABELLED: There is a need for a user-friendly system that can provide quick and reliable assessment of foot disorders. The study described in this report was undertaken to determine the inter-rater and intra-rater reliability of a computer-aided, color-coded, video-based system developed for the assessment of foot alignment in patients with and without pes cavus deformity. Initially, 15 pedal angles were repetitively measured 7 times on 6 color-coded images of both feet, in 20 healthy adults. From the 7 repetitive measurements, the intra-class correlation was calculated and analysis of variance was used to estimate the minimum number of trials that would be necessary to identify a statistically significant difference in the measurements. To determine intra-rater reliability, 5 examiners evaluated a single set of data taken from 10 subjects. Additionally, data were obtained for 20 subjects with pes cavus deformity. The average intra-class correlation coefficient (ICC) for the anglular measurements for 2 to 7 trials was 0.98 +/- 0.06, while the intra-rater reliability was 0.90 +/- 0.14. No statistically significant differences were observed between right and left foot angles in able-bodied subjects; whereas, in the pes cavus group, 8 different angular measurements were observed to be statistically significantly different. The results of this investigation indicate that a computer-aided, color-coded, video-based system can be used to make reliable measurements of postural alignment in patients with and without pes cavus. LEVEL OF CLINICAL EVIDENCE: 5.

Relations between standing stability and body posture parameters in adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective study of standing imbalance and body posture in 71 able-bodied girls and subjects with adolescent idiopathic scoliosis was conducted. OBJECTIVE: To test the hypothesis that postural parameters are related to standing stability parameters. SUMMARY OF BACKGROUND DATA: Spinal deformity not only modifies the shape of the trunk, but also changes the relations between body segments affecting posture in scoliotic children. These postural adaptations to the scoliotic curve progression could be linked in part to increased body sway in upright standing. This has not yet been related to specific postural parameters involving the head, trunk, and pelvis in nontreated idiopathic scoliosis. METHODS: The head, trunk, and pelvis orientations of each subject were measured by a Flock of Bird system. An AMTI force platform was used to assess quiet standing stability and to monitor the position and displacement of the center of pressure (COP). The center of mass (COM) excursion was estimated from a biomechanical model using force plate information only. Analyses of variance (ANOVAS) were performed to determine the statistical differences between the scoliotic and nonscoliotic subjects, and backward stepwise multiple regression analyses were performed to identify any correlation between measures of quiet standing stability and body postural parameters RESULTS: The scoliotic group was characterized by a decrease in standing stability. There was an increase in the sway areas measured by the variations of the COP and COM. From the backward stepwise multiple regression analysis, it appears that for the able-bodied girls, the body posture parameters were correlated only with the mean anteroposterior center of pressure (COP(AP)) position. For the scoliotic group, the sway areas and the mean position of the centers of pressure and the COP(AP)-COM(AP) were correlated significantly with body posture parameters. The higher COP-COM differences for the scoliotic group were attributed to a greater neuromuscular demand to maintain standing balance. The coefficients of correlation of the multiple regression analyses ranged from 0.64 to 0.85 for the nonscoliotic group and from 0.55 to 0.72 for the scoliotic group. CONCLUSIONS: The use of backward stepwise multiple correlations highlighted the interaction between several body parameters and their relation to standing stability in both able-bodied girls and scoliotic subjects. The scoliotic group displayed a much larger number of correlations between standing stability and body posture parameters than the nonscoliotic group. Standing imbalance was related to altered body posture parameters measured in the frontal and horizontal planes only. Although the correlation coefficients were relatively high, factors other than body posture parameters appeared related to standing imbalance in adolescent idiopathic scoliosis. These findings support the concept of either a primary or a secondary dysfunction in the postural regulation system of scoliotic subjects.