Ground reaction force complexity in hallux valgus.

BACKGROUND: Investigating the complexity of movement systems can be insightful in clinical decision making. The study conducted to evaluate whether complexity of ground reaction force is affected by hallux valgus grades and footwear or foot side conditions. METHODS: A sample of 120 females including 30 participants in each group of healthy and mild, moderate, and severe hallux valgus were recruited in this case-control study. Hallux valgus grades were assessed using Manchester scale. Ground reaction force were measured in bare foot and shod conditions for both feet and weighted permutation entropy was used to calculate the complexity. Nonparametric tests were employed for statistical inference. FINDINGS: The first important result was that hallux valgus caused loss of complexity of ground reaction force with a medium to large effect size. However, we did not find any difference between three grades of hallux valgus entropy. The second finding was that entropy of healthy group decreased from barefoot to shod condition with a large effect size and the third finding was that ground reaction force entropy were similar in both feet. INTERPRETATION: The findings are aligned with the theory that loss of complexity appears when the biological systems become functionally impaired. As soon as hallux valgus initiates, all potential risks related to the reduction of complexity appear. So, we suggest to administer conservative treatments in the early stages of hallux valgus. The study outcomes can be used for evaluation of foot function, classification of the foot types, or footwear selection.

Foot structural factors and ground reaction force in hallux valgus grades.

BACKGROUND: Little attention has been paid to foot structural factors and ground reaction force in hallux valgus. Investigating the structural factors in detail and determining their biomechanical effects can help to better manage hallux valgus. METHODS: In this case-control study, 120 females, 90 hallux valgus and 30 healthy, were recruited. Hallux valgus grades (mild, moderate, severe), first metatarsal mobility, foot pronation, hallux rotation, and pain were assessed by clinical tests. Ground reaction forces were measured in barefoot and shod conditions for both feet and analyzed using mixed within-between MANOVA. The association between structural factors and pain with force was analyzed using Spearman correlation coefficient. RESULTS: The frequency of foot structural factors and pain severity were reported in hallux valgus grades. A significant difference was seen in the force values between groups (P<0.001). Bonferroni post hoc test indicated that the mean of the first peak for the severe group was significantly higher than the mild group (P=0.013) and the mean of second peak for the moderate group was higher than that of the healthy group (P=0.009). The force values were affected by wearing shoe (P<0.001) but not by foot side (P=0.086). There was a medium, positive correlation between the hallux rotation and force in the moderate group (r=0.39, P=0.03) and also between the pronation and force in the severe group (r=0.36, P=0.04). CONCLUSION: Foot structural factors, pain, and force were different in each hallux valgus grads. Similar force in both feet, and increased force by wearing shoe were seen. The relationship between the pronation and hallux rotation with force revealed the importance of these factors from the biomechanical viewpoint.

Triple Tendon Transfer for Correction of Foot Deformity in Common Peroneal Nerve Palsy.

BACKGROUND: Anterior transfer of posterior tibial tendon (PTT) is the most common technique to correct foot drop in patients with common peroneal nerve palsy. It does not address the loss of toe extension or "toe drop." This may affect the gait pattern, and patients may not tolerate it. Described here is a technique that addresses toe drop associated with common peroneal nerve palsy. METHOD: A new technique of tendon transfer using the PTT, flexor hallucis longus (FHL) tendon, and flexor digitorum longus (FDL) tendon was performed on 15 patients (13 males and 2 females) with complete common peroneal nerve palsy from 2009 to 2013. Minimum follow-up was 12 months (range, 12-50 months). The mean age was 37 years (range, 20-52 years). RESULTS: Based on the evaluation criteria of Carayon et al, the postoperative results for foot drop correction were excellent in 9 (60%), good in 5 (33%), and moderate in 1 (7%), and the mean active range of motion of the ankle was 46 degrees. Postoperative extension evaluation of the toes was excellent in 7 (47%), good in 5 (33%), and moderate in 3 (20%). CONCLUSION: Releasing and transferring of FDL and FHL to the toe extensors along with the anterior transfer of the PTT neutralized the deforming forces and allowed for active toe extension while strengthening ankle dorsiflexion. Movahedi Tendon Transfer was a reliable method to achieve a balanced foot and toe dorsiflexion for complete common peroneal nerve palsy. LEVEL OF EVIDENCE: Level IV, retrospective case series.

The evaluation of modified foot orthosis on muscle activity and kinetic in a subject with flexible flat foot : single case study.

BACKGROUND: Due to blocking of pronation/dorsiflexion in flexible flat foot and restriction of these movements in using the University of California Berkeley Laboratory orthosis, provided pressures in sole by the orthosis were increased. Therefore, this article describes the evaluation of modified foot orthosis with flexible structure in the management of individuals with flexible flat foot. CASE DESCRIPTION AND METHOD: The patient was a 21-year-old male who had symptomatic flat foot. The modified foot orthosis included movable surface and the outside structure. The modified foot orthosis was evaluated by standing foot X-ray, comfort rate, electromyography of leg muscle and vertical ground reaction force during walking. FINDINGS AND OUTCOMES: The modified foot orthosis improved the foot alignment and decreased the symptoms of flat foot with more comfort. Subtalar position by sub-maximum supination had higher position than neutral in sagittal plane. It may increase the muscle activity of peroneus longus by 7% compared to barefoot, and there was a decrease of 11% ground reaction force in mid stance. CONCLUSION: The result of this single case evaluation only proposed the feasibility of this modified insole as the orthotic treatment in flexible flat foot. Clinical relevance The modified foot orthosis, which is mobile in the midfoot, is an orthosis for walking and standing in subjects with flexible flat foot.