Effect of Insole Added to Exercise in Patients With Bilateral Flexible Flatfoot

Pesplanus, commonly known as 'flatfoot,' is a common pathomechanical condition characterized by a lowered medial longitudinal arch (MLA) and exaggerated pronation. There are two general types of flatfoot : flexible flatfoot and rigid flatfoot Flexible flatfoot is the most common form of flat foot. In adult population, it was reported that prevalence of flexible flatfeet is 13.6%. It has been proved that there is static and dynamic balance deficit in the participants with flatfeet. The extrinsic muscles as posterior tibialis (TP) ) and intrinsic muscles as abductor hallucis (AbdH) act as active subsystem support for the MLA during weight-bearing, standing, and walking. Abnormal alignment of the foot may cause stretch weakness of the foot muscles by elongating beyond the neutral physiological resting position. leading to musculoskeletal dysfunction and overuse injuries. Insoles can assist in maintaining normal alignment of the foot, improve balance as it supports MLA which is essential to stabilize postural sway, they widen the contact surface of the sole of the foot improving stability.

Insoles have been used to correct pathomechanical alterations that occur in patients with flexible flat feet, it was reported that they reduced ankle eversion, ankle inversion moment and reduced the load placed on the ankle invertor muscles which must act eccentrically to control over-pronation and support the arch. Insole with intrinsic foot muscle training has been reported to increase strength on flexor hallucis and cross-sectional area of the AbdH muscle in patient with pes planus. Therefore insole combined with short foot exercises is recommended for strengthening intrinsic foot muscles in pes planus.

Wearing hard insole has been reported to improve postural stability as it limits and control the range of foot pronation, correct foot malalignment and promotes a neutral foot position.

Many studies had investigated the effect of using insole alone or exercise program alone or comparing between them on flexible flat foot patients. Up to the knowledge of the primary investigator, this is the first study to investigate the effect of adding arch support insole to strengthening exercise of foot muscles (intrinsic or extrinsic) in terms of dynamic balance, foot function, and foot muscle strength (intrinsic or extrinsic).

Eligibility Criteria:
Inclusion Criteria:

1. Navicular drop tests (NDT) 10 mm or larger difference in the navicular tuberosity heights.
2. Age range from 18-30 years from both sexes to limit the effects of arthritic changes that would be caused by bilateral FFF over the age 30.
3. BMI 18-30 as the prevalence of flexible flatfoot appears to be higher in individuals with a higher body mass index (BMI).

Exclusion Criteria:

1. history of lower extremity injuries as fractures, congenital deformities or surgery affecting balance.
2. history of cerebral concussions affecting balance.
3. visual or vestibular disorders, and/or any neurological deficit affecting balance.
4. any sign of foot pain, history of patellofemoral pain syndrome, plantar fasciitis, TA or TP dysfunction affecting foot function and balance.