High arched foot is a common foot deformity, mostly caused by neuromuscular disorders that result in fixed plantar flexion of the forefoot, thereby increasing the longitudinal arch of the foot. Sometimes it is combined with hindfoot pronation deformity. Occasionally, the cause is unknown, and it can be called idiopathic high arched foot. There are five common types: high arched supinated foot, high arched claw foot, high arched pronated foot, high turned foot and high arched heeled foot. High arch supinated toe foot and high arch heel foot is mainly due to paralysis of the gastrocnemius and hallux valgus muscles, while part of the dorsal extensor muscles of the foot is strong, while metatarsal tendon contracture of the two often combined; high arch claw foot is due to imbalance of muscle strength of the intrinsic muscles of the foot or a group or groups of extrinsic muscles of the foot, and metatarsal ciliary contracture; if the internal and external muscles of the foot are unbalanced, it is also often accompanied by inversion and valgus deformity of the foot.
I. Etiology
Most of the cases are neuromuscular diseases, which cause the arch to be lowered by dynamic factors such as weakening of the anterior tibial muscles or/and triceps calf muscles, and contracture of the intrinsic muscles on the plantar side of the foot, resulting in an increase in the longitudinal arch of the foot. These neuromuscular disorders can occur at different levels of the conus cerebri, cortical tracts of the spinal cord, anterior horn cells of the spinal cord, peripheral nerves and muscles. Common disorders include spinal cord torticollis, cerebral palsy, cerebrospinal spinal bulge, and neural tube closure insufficiency. Other disorders are less common, such as spinal longitudinal fracture, spinal cord embolism syndrome, and Charcot-Marie-Tooth disease.
Certain cases with a clear family history and no evidence of neuromuscular pathology may be congenital, or are referred to as idiopathic hyperkyphosis.
II. Clinical manifestations
According to the degree of arch elevation and whether it is accompanied by other deformities of the foot, the high arched foot is usually divided into four types.
1, simple high arch foot
Mainly the forefoot has a fixed plantar flexion deformity, and the first and fifth metatarsals are evenly weight-bearing. The medial and lateral longitudinal arches of the foot are uniformly increased, and the heel remains in a neutral position, or there is mild valgus.
2, inversion type high arch foot
This type only the forefoot medial column that the first and second metatarsal plantarflexion deformity, so that the internal longitudinal arch of the foot increased. And the external longitudinal arch is still normal. The fifth metatarsal is easily elevated to neutral position when not bearing weight, while the first metatarsal cannot be passively dorsally extended to neutral position due to fixed plantarflexion, and has 20-30° of internal rotation deformity. Initially, the hindfoot is mostly normal. When standing and walking, the pressure on the first metatarsal head increases significantly. In order to reduce the pressure on the first metatarsal head, the patient often adopts an inversion position to bear weight, and in the late stage, a fixed inversion deformity of the hindfoot appears. Patients mostly have claw toes, the first metatarsal head protrudes to the bottom of the foot, the plantar weight-bearing area of soft tissue thickening, callus formation and pain.
3.Following type high arched foot
Commonly seen in poliomyelitis, spinal cord bulge. Mainly due to triceps calf paralysis, characterized by the heel bone in dorsal extension, forefoot fixed in plantarflexion position.
4, plantar flexion type high arched foot
Mostly secondary to congenital clubfoot after surgical treatment. In addition to the fixed plantar flexion deformity of the forefoot, this type also has a pronounced plantar flexion deformity of the hindfoot and ankle joint. The clinical manifestations of each type of clubfoot are not consistent, but all forefeet have fixed plantarflexion deformity. The toes are normal in the early stage, but as the disease progresses, the toes gradually recede backward, the interphalangeal joints are plantarflexed, the metatarsophalangeal joints are excessively dorsiflexed, and there is a claw-like toe deformity, and in severe cases, the toes cannot touch the ground. Due to the dorsiflexion deformity of the metatarsophalangeal joint, the metatarsophalangeal joint is subluxed, so that the base of the proximal phalanx is pressed against the dorsal side of the metatarsal head.
Examination
The main method of examination for this disease is X-ray examination.
X-ray examination should be taken under the weight-bearing conditions of the frontal and lateral X-rays of the foot. M′eary measures the angle between the mid-axis of the talus and the mid-axis of the first metatarsal, and the two lines are continuous when the arch of the foot is normal. If the angle can be measured, it indicates an increased arch.
Hibbs measured the angle between the median axis of the heel bone and the median axis of the first metatarsal bone, and the normal value is 150-175°. This angle is reduced in high arch deformities. In addition, orthopantomographs measure the heel spacing angle, and if it is <20°, it indicates a hindfoot pronation deformity.
IV. Differential diagnosis
The diagnosis of high arched foot can be made based on the abnormal gait, increased longitudinal arch with claw toe deformity, and increased M′eary angle and decreased Hibbs angle on X-ray examination. However, high arched foot is mostly a deformity caused by neuromuscular diseases, and further examination should be done to find the primary disease or potential pathogenic factors, such as electromyography, cranial or spinal cord CT or MRI examination. It is important to determine the prognosis by clarifying the cause.
V. Treatment
1.Non-surgical treatment
Early mild high arched foot can be treated by passively pulling the contracted plantar fascia and the shortened intrinsic plantar muscle. In order to relieve the pressure on the metatarsal head, so that the weight is evenly distributed, add a 1cm thick felt pad at the metatarsal head in the shoe, and thicken 0.3 to 0.5cm on the rear side of the sole, in order to reduce the tendency of inversion of the rear foot when walking. However, these measures can only reduce the symptoms, neither correct the high arched foot deformity, nor prevent the deformity from worsening.
When the high arched foot has prevented weight-bearing walking, wearing shoes, or progressive aggravation, then surgery should be performed. Surgical methods can be divided into soft tissue release and bony surgery. The surgical method is generally selected according to the patient’s age, the type and severity of the deformity, and the state in which the primary disease is located. In principle, soft tissue surgery is performed first, such as soft tissue release of the plantar side of the foot, displacement of the anterior and posterior tibial tendons and posterior displacement of the long toe extensors. If soft tissue surgery still fails to correct the deformity, or if older children have fixed high arched foot deformity, bone orthopedic surgery can be chosen.
2.Surgical treatment
A traditional method is to release the soft tissues on the metatarsal side of the foot, revealing the soft tissues on the metatarsal side through a longitudinal incision on the posterior side of the inner edge of the foot, first cutting the metatarsal fascia and the long metatarsal ligament, and then stripping the
(1) A transverse or longitudinal incision is made on the dorsum of the foot to reveal the tarsus outside the periosteum.
(2) Design a V-shaped osteotomy line at the apex of the arch, which is usually located in the middle of the navicular bone, with the medial branch sloping from the navicular bone to the medial cortex of the first cuneiform bone.
(3) After completing the osteotomy, the surgeon pulls the forefoot distally and elevates the forefoot, while pressing down on the distal end of the osteotomy. If there is internal rotation and adduction deformity, the forefoot can be externally rotated and abducted to pre-correct it. Then a kerf pin is inserted medially through the first metatarsal and stops at the lateral portion of the heel bone through the osteotomy line. After surgery, the lower leg is immobilized in a cast for six weeks. After release of the cast, the pin was removed and x-rays were taken to observe the healing of the osteotomy. If it has healed, weight-bearing walking can be started gradually.