bubble_chart Overview

The incidence of congenital talipes equinovarus is 1%, accounting for 85% of foot deformities. The male-to-female ratio is 2:1. Some patients may have deformities in other areas, such as congenital hip dislocation or stenosing tenosynovitis. The deformity is easily detectable, allowing for timely treatment. However, it is essential to communicate with the family that treatment must be persistent and not abandoned midway. Long-term follow-up until skeletal maturity (approximately 14 years of age) is necessary; otherwise, partial recurrence may lead to residual deformity.

bubble_chart Etiology

There are many hypotheses about the disease cause of this condition, such as environmental factors, embryonic developmental abnormalities, and genetics, but none can be confirmed with certainty.

Bōhm believes that the fetal foot gradually develops from a position of equinus, adduction, and varus to a normal position during embryonic development. During this process, deformity may occur due to certain factors or primary defects in the embryo.

Dunn suggests that the deformity results from the fetus being compressed in the uterus, causing the forefoot to be pressed into adduction, supination, and plantar flexion. Stewart observed that Japanese residents in the Hawaiian Islands, who habitually sit with their feet inverted, have a higher incidence of the condition. This may be due to the sitting posture increasing the likelihood of uterine compression on the fetus, leading to a higher incidence.

Wynne-Davis conducted a family survey of 144 cases from a genetic perspective and concluded that some cases involve genetic abnormalities, but the patterns of dominant or recessive inheritance have not yet been identified.

Other theories include Stewart's suggestion that it is related to abnormal muscle insertions. Moore found neural abnormalities, while Sherman attributed it to talar deformities.

The current view is that various factors combine in complex ways to produce deformities of varying degrees, and it is by no means due to a single cause.

bubble_chart Pathological Changes

This disease encompasses four types of deformities: (1) metatarsus adductus and internal rotation of the forefoot; (2) varus of the hindfoot; (3) ankle joint equinus; (4) internal rotation of the tibia. Most scholars believe that the primary pathology lies in the tarsal bones, particularly the talus, where the most significant changes occur, leading to the deformities. Over time, soft tissues develop contractures, making the deformities more fixed. During continued development, bones grow vigorously in areas with less pressure but are hindered in areas with greater pressure, gradually forming bony deformities.

The bony changes occur first: (1) In a normal foot, the longitudinal axis of the talar body and its head-neck forms an angle of 150°–155°, whereas in deformity, this angle becomes 115°–120°, causing the talonavicular joint surface of the talar head to shift from facing forward to facing inward toward the metatarsus. From a lateral view, the longitudinal axis of the talus shifts from the superolateral to the downward direction, resulting in a similar shift and medial rotation of the calcaneus. The talus assumes a metatarsus flexion position relative to the tibia. (2) The shape of the calcaneus remains unchanged, but due to displacement with the talus, it assumes a plantarflexed and internally rotated position, forming a concave arch facing medially. The posterolateral calcaneus contacts the posterior aspect of the lateral malleolus, and the sustentaculum tali contacts the tip of the medial malleolus. (3) The navicular bone is smaller than normal and slightly displaced medially, forming an articular surface on the medial side of the talar head, resulting in an adduction deformity. (4) Other bones, such as the cuneiform and metatarsal bones, show no deformity in the early stages.

The soft tissue changes are secondary. With age, the skin, muscles, ligaments, joint capsules, blood vessels, nerves, and other tissues undergo varying degrees of changes, such as: (1) Contracture or shortening of the medial soft tissues of the foot, including the deltoid ligament, talonavicular ligament, calcaneonavicular ligament, tibialis posterior, flexor digitorum longus, and flexor hallucis longus. (2) Laxity of the muscles and ligaments on the dorsum and lateral side of the foot. (3) Shortening or contracture of the posterior joint capsules of the ankle and subtalar joints, calcaneofibular ligament, posterior talofibular ligament, and triceps surae. (4) Shortening of the interosseous talocalcaneal ligament, metatarsal tendon membrane, abductor hallucis, flexor digitorum brevis, and abductor digiti minimi in the sole of the foot.

bubble_chart Clinical Manifestations

Foot drop, with the heel tilted upward, the lateral edge of the foot touching the ground, and the sole facing backward, resembling a golf club, hence the condition is also called clubfoot. Due to the above phenomena, the heel is inverted, the forefoot is adducted, and the talar head protrudes dorsally and laterally.

The deformity can be divided into two types: (1) The slender type (relaxed type) features a small and thin foot with mild deformity, easily manually adjusted to a neutral position, and calf circumference similar to the unaffected side. Non-surgical treatment yields good results. (2) The short and thick type (rigid type) presents with a plump and short foot, a small heel, severe deformity, and a calf circumference thinner than the unaffected side. The deformity is difficult to manually correct and often requires surgical intervention.

X-ray findings: Anteroposterior X-ray shows a talocalcaneal angle (the angle between the axis of the talus and the axis of the calcaneus) < 30°. The angle between the longitudinal axis of the talus and the longitudinal axis of the metatarsus is 0°–20° (Figure 1). Combining the measurements of these two angles can aid in diagnosis. Lateral X-ray shows the angle between the longitudinal axis of the talus and the tangent of the metatarsal surface of the calcaneus < 30°; otherwise, foot drop is present.

bubble_chart Treatment Measures

As early as the time of Hippocrates, there were treatment methods involving manual correction and bandage fixation, followed later by subcutaneous Achilles tendonotomy for orthopedic purposes. In the 16th century, violent correction methods emerged, and this one-time mechanical correction approach is still used today. However, this method causes soft tissue {|###|}injury, leading to local bleeding, fibrosis, and scar contracture, with severe consequences. As a result, it has been opposed by most scholars in recent years. In 1930, Kite reported a gradual wedge-shaped gypsum excision correction method, which remains one of the best non-surgical treatments to this day. In recent years, surgical treatment has been advocated for cases where non-surgical methods fail, for patients aged 3–5 years or older, and for those with short, broad feet.

(1) Non-surgical treatment methods

These are suitable for newborns and young children, with various approaches such as manual correction combined with adhesive tape fixation, gradual gypsum correction, wedge-shaped gypsum excision for gradual correction (Kite’s method), and the Dennis-Browne splint method. Regardless of the method, the treatment principles are similar: the earlier the treatment begins, the better the outcome, and it should start during the neonatal period. The correction steps should follow the sequence of first addressing adduction, then inversion, and finally equinus deformity. If adduction deformity is not corrected, the navicular bone remains medial to the talar head; after correction, it moves anterior to the talus, aligning the weight-bearing lines of the forefoot and hindfoot in a straight line, reducing the likelihood of recurrence.

If adduction deformity is not corrected first, the weight-bearing line and muscle forces are misaligned, making it difficult to correct inversion due to the pull of the tibialis anterior and posterior muscles. Overcorrection of adduction can displace the navicular bone laterally to the talus, leading to flatfoot. If inversion is not corrected before addressing equinus, about half of the talus remains anterior and superior to the calcaneus (during correction, the talus gradually moves posteriorly while the calcaneus moves anteriorly to its normal position). Simultaneously, the pull of the tibialis posterior and gastrocnemius muscles prevents ankle dorsiflexion, concentrating dorsiflexion stress on the midtarsal joints and resulting in a rocker-bottom foot. This can cause adhesions in the talocalcaneal and tarsal joints, leading to stubborn deformities. Both medical staff and family members must persist with treatment and ensure long-term follow-up, never abandoning it midway.

The modified Kite method, involving gradual wedge-shaped gypsum excision: First, apply a gypsum boot to the deformed foot. After drying, perform a wedge-shaped gypsum excision at the tarsal region, then close the wedge gap and reinforce it with gypsum, fixing it in an inverted equinus position with a short-leg gypsum cast. For short, broad feet, use a long-leg gypsum cast with the knee flexed. Perform wedge-shaped gypsum excision once a week to gradually correct the deformity. Typically, after 1–2 wedge excisions, the gypsum must be replaced. After 4–6 sessions, the adduction deformity can be corrected.

After correcting the adduction deformity, proceed to correct the inversion deformity. Similarly, apply a gypsum boot, and after drying, remove a portion of the gypsum near the lateral malleolus (creating a shoe-like shape). Hold the entire gypsum boot and gently exert force to evert it as much as possible, then fix it in this position with a short- or long-leg gypsum cast. Perform weekly wedge-shaped gypsum excisions near the lateral malleolus, usually requiring 4–6 sessions to correct the inversion deformity. Once the adduction and inversion deformities are corrected, perform a subcutaneous Achilles tendonotomy in the outpatient operating room. Postoperatively, apply a gypsum boot, excise the gypsum over the ankle dorsum, and use a board to dorsiflex and evert the ankle (to prevent rocker-bottom foot), fixing it with a short- or long-leg gypsum cast. After four weeks, replace the gypsum cast in a neutral position, concluding the treatment. Regular follow-up is essential; if recurrence occurs, gypsum correction can typically address it in about four weeks. Without proper follow-up and management, recurrence may lead to permanent deformity.

(2) Surgical therapy

Suitable for cases where non-surgical treatment fails or for older patients. There are many surgical methods, which can be categorized into three types: soft tissue release, tendon transfer, and bone surgery.

1. Soft Tissue Release: Suitable for children aged 3 to 7 years. During the surgery, the deformity must be completely corrected, and residual deformities should not be left to postoperative gypsum correction. There are numerous surgical procedures, and the following are highlighted as key examples.
   1. Correction of metatarsus adductus: A metatarsal tarsal capsulotomy (Heyman method) can be performed. A transverse curved incision or 2-3 small longitudinal incisions are made on the dorsum of the foot to expose the 1st to 5th metatarsal tarsal joints. The medial, lateral, and anterior joint capsules are incised to correct the adduction deformity. A short-leg gypsum cast is applied to maintain the forefoot in the corrected position for 3 months.
   2. Correction of varus deformity can be achieved through medial foot release, with the Ober and Brockman methods being the most commonly used. This article describes the Ober method: A curved incision is made from the distal tibia at the medial malleolus to the naviculocuneiform joint to expose the distal tibia and medial malleolus. A "Λ"-shaped incision is made in the periosteum above the medial malleolus, and the periosteum along with the deltoid ligament is reflected downward. The surrounding soft tissues are dissected from the ankle, and the dissection continues along the talus, calcaneus, talocalcaneal joint, and talonavicular joint, with the talocalcaneal ligament being transected. During the procedure, the neurovascular bundle and tendons can be retracted. If necessary, the tendons can be lengthened via "Z"-plasty and then repaired, or the calcaneofibular ligament can be transected. After deformity correction, gypsum immobilization is applied for 8 weeks.
   3. Correction of equinus deformity can be achieved through Achilles tendon lengthening. If there is medial displacement of the Achilles tendon insertion, the tendon can be repositioned and sutured during lengthening (Figure 5).
2. Tendon transfer: In recurrent cases where the deformity can be manually corrected, if the recurrence is due to muscle imbalance, surgery can be performed following the treatment principles for sequelae of poliomyelitis.
3. Bone surgery: Calcaneal osteotomy is suitable for children aged 3-8 years with hindfoot varus deformity. There are two osteotomy methods: opening or closing wedge. The opening wedge involves making an incision on the medial side of the calcaneus and inserting a bone graft, while the closing wedge involves removing a wedge of bone from the lateral side of the calcaneus and closing the osteotomy site.

Arthrodesis is suitable for patients over 12 years of age with bony deformities. Commonly performed procedures include calcaneocuboid, talocalcaneal, and triple arthrodesis (talonavicular, calcaneocuboid, and talocalcaneal joints).

The selection of the most appropriate method among those described above must be based on the patient's age, the severity of the deformity, and the surgeon's experience and skill level. Improper treatment may lead to various complications.