What is Congenital Vertical Talus?
Congenital vertical talus is a condition where the foot is angled downwards and twisted outwards. It’s often accompanied by other foot flaws, including sideways rotation at the front of the foot and an upward bend in the middle of the foot. This is mainly due to the navicular bone in the foot being dislocated upwards over the head of the talus bone.
In 1913, the term ‘Congenital vertical talus’ was first used by Rocher to describe this condition. It’s been called by other names throughout history, such as reversed club foot, congenital valgus flat foot, pied plat valgus congenital, congenital convex pes valgus, and rocker bottom foot. Nowadays, the most commonly used term is ‘congenital convex pes valgus’.
This foot condition has also been linked to other health problems, including undescended testicles, a smaller head size, and injuries at birth due to a lack of oxygen. If undiagnosed or not treated appropriately, it can lead to significant disability, causing painful calluses to form around the protruding head of the talus bone and serious ankle and foot pain.
In the past, the surgery to correct congenital vertical talus was quite invasive, carrying a high risk of complications. Today, less intrusive techniques are used, showing promising outcomes in correcting the deformity and limiting the release of soft tissue.
What Causes Congenital Vertical Talus?
The exact cause of a birth defect called ‘congenital vertical talus’ is still a topic of debate. More than half of these cases occur for unknown reasons, and the rest are generally linked to genetic or neuromuscular conditions. Congenital vertical talus can occur on its own or as a part of a larger systemic condition. In rare cases, it can be associated with a condition that’s not part of a syndrome.
Conditions often found with congenital vertical talus include Marfan syndrome, De Barsy Syndrome, chromosomal abnormalities like the ones of 13, 15, 18, 30, and 31, multiple pterygium syndrome, Cri du chat syndrome, and various muscle abnormalities like the ischiocalcaneal band, spinal irregularities, migration defects, and fetal brain disorders.
Other possible causes are increased pressure inside the womb, muscle imbalance, slow growth in the womb, and halted developmental growth or the rotational development of the foot.
Risk Factors and Frequency for Congenital Vertical Talus
Congenital vertical talus, a rare condition, is found in about 1 in 10,000 newborn babies. Its rarity can make it hard to identify in new infants.
Signs and Symptoms of Congenital Vertical Talus
If a child is thought to have a birth defect known as ‘congenital vertical talus’, it’s important to gather a complete history from their parent or caregiver. This history should cover the period before birth, during birth, and after birth.
Congenital vertical talus usually has certain characteristic signs. These include abnormal positions of the foot: bending and pointing downwards in the back of the foot, the front of the foot curving outward, and the middle of the foot bending upwards.
Because of the unusual vertical position of the talus bone (a foot bone) and weakening of a foot ligament known as the ‘spring ligament’, a bump can form on the bottom side of the foot. This eventually gives the foot a curved, ‘rocker-bottom’ look. Deep creases are easily visible on the top outer side of the foot. The head of the talus bone may be felt as a hard lump on the inside and bottom sides of the middle of the foot.
If this condition isn’t treated, it can make the foot stiffer and changes in the foot bones can develop. When the child starts to bear weight on their foot, hard skin (callosities) forms around the head of the talus bone along the inside edge of the foot. The front of their foot bends outward and this stiffness prevents the heel from touching the ground. For all patients with congenital vertical talus, it’s necessary to fully examine the nervous system to check for any related abnormalities.
Testing for Congenital Vertical Talus
Medical imaging from different angles should be done for a foot, especially in infants or children older enough to bear weight standing. This is important in diagnosing congenital vertical talus (a foot defect present at birth), even though it can be quite tricky due to many bones in the foot not yet being fully formed at birth.
In most cases, the significant bones such as the metatarsals, tibia (shin bone), calcaneus (heel bone), and talus (ankle bone) are formed at birth. The cuboid bone, a smaller foot bone, forms during the child’s first month. The navicular bone and three cuneiform bones, which are located between the ankle and the metatarsals, are usually fully formed by the time the child is between 2 and 3 years old.
Since congenital vertical talus most commonly presents in newborns, understanding the positioning of the formed bones, particularly the talus and calcaneus, in relation to the shin bone and the metatarsals is crucial when inspecting medical images.
Key indicators in the images can include an increased angle between the talus and calcaneus bones. The talus bone might appear vertical and parallel to the shin bone. Additional images taken while the foot is flexed in different directions (dorsiflexion – upward bending, and plantar flexion – downward bending), can also help to confirm the presence of vertical talus and rule out similar conditions such as calcaneovalgus and oblique talus.
For instance, when viewing side images of the foot during dorsiflexion, doctors may observe a decreased angle between the shin and the heel bone, and the talus bone may not align correctly with the navicular bone. In plantar flexion, the talus bone might not align correctly with the first metatarsal (the bone in the foot that leads up to the big toe).
Treatment Options for Congenital Vertical Talus
The primary goal of treating a condition called congenital vertical talus is to restore normal foot function. This is achieved by correctly aligning the talus, calcaneum, and navicular bones in the foot. Non-surgical treatments may involve manipulation and repeated casting of the foot.
However, the effectiveness of early casting in cases of congenital vertical talus is unpredictable and differs from another foot deformity, congenital talipes equino varus, where early casting often leads to successful outcomes. If non-surgical management doesn’t work, surgery might be needed. This can be done all at once or in several stages. Some surgeons may try non-surgical treatment first, with casting to adjust the talonavicular joint, followed by minimal surgery if needed.
Surgery is usually recommended for children below two years of age. Several surgical procedures are available for treating congenital vertical talus, and the choice of surgery largely depends on how severe the deformity is, the age of the patient, and the surgeon’s personal preference.
For kids under two years, surgical treatment often involves open reduction of the talonavicular joint. This can be done in one or two stages. A two-stage approach includes reducing the talonavicular joint and extending the extensor and tibialis anterior tendons in the first stage. The second stage lengthens the ankle tendons, corrects the contracture of the Achilles tendon, and releases the soft tissues at the back of the ankle and subtalar.
Yet, many surgeons now prefer to do everything in one stage due to a reduced risk of complications like avascular necrosis of the talus bone. A one-stage procedure generally involves three main steps – reducing the talonavicular joint, lengthening the ankle and toe extensors, and correcting the ankle contracture by extending the Achilles tendon and releasing the subtalar and ankle joint capsules.
What else can Congenital Vertical Talus be?
Congenital vertical talus is a unique foot deformity. It is very different to other foot conditions, including clubfoot, calcaneovalgus foot, and bend of the shin bone known as posterior medial bowing of the tibia. If a child has congenital vertical talus, a specific joint in the foot (called the talonavicular joint) is misplaced and is pointed inwards and downwards. If it’s clubfoot, this joint moves outwards and upwards.
For a calcaneovalgus foot condition, there will be a noticeable space between the talus bone and the navicular bone (two bones in the foot), caused by the bending of the foot at the midtarsal joints. However, this space disappears when the foot is bent downwards. This is how doctors can tell these conditions apart.
What to expect with Congenital Vertical Talus
The outlook for the condition can change and it primarily relies on the age at which the condition was identified, and how far it has advanced when it was diagnosed.
Possible Complications When Diagnosed with Congenital Vertical Talus
If not treated, congenital vertical talus can lead to a number of symptoms and problems. These can include abnormal bone shapes causing the foot to look like a rocker bottom, the formation of hardened skin lesions known as calluses, and difficulty wearing shoes. There may also be further complications, often due to related health problems or from surgical procedures.
These possible outcomes of untreated congenital vertical talus include:
- Abnormal bone shapes leading to a “rocker-bottom” appearance
- The formation of calluses
- Difficulty wearing shoes
- Complications due to related health issues or surgery, if needed
Recovery from Congenital Vertical Talus
After the correction of a deformity through manipulation and serial casting, there’s still a high risk of it coming back. This is why postoperative rehabilitation, including bracing and stretching, is very important in preventing a relapse. Parents need to ensure that their child wears a brace for no less than 23 hours a day in the first three months. After that, the brace should be worn for at least 12 to 14 hours a day for a minimum of two years.
Furthermore, parents should also learn stretching exercises for their child’s foot. These exercises must be done each time they change the child’s diaper to help maintain the flexibility of the foot.
Preventing Congenital Vertical Talus
Children with a condition known as congenital vertical talus need immediate medical attention and treatment. If not handled correctly, this condition can lead to serious, long-term physical issues. The aim of treatment methods is to get the foot functioning normally by re-aligning the bones in the foot to their proper position.
