Congenital vertical talus (CVT), also known as rocker-bottom foot, is a rare and complex congenital foot deformity characterized by a rigid flatfoot with a convex sole. This condition is typically diagnosed at birth and, if left untreated, can lead to significant functional impairment and discomfort later in life. Though uncommon, CVT poses diagnostic and therapeutic challenges that require early intervention and multidisciplinary care.
Anatomy and Pathophysiology
The talus is a small bone situated between the heel bone (calcaneus) and the bones of the lower leg (tibia and fibula), forming the ankle joint. It plays a crucial role in weight transmission and foot mobility. In congenital vertical talus, the talus bone is abnormally positioned in a vertical orientation, causing misalignment of the surrounding bones. This results in a dorsal dislocation of the navicular bone and a rigid flatfoot deformity. The foot appears convex on the bottom, with the forefoot dorsiflexed and abducted, and the hindfoot in equinovalgus due to contractures of the Achilles and peroneal tendons.
Epidemiology and Etiology
CVT is a rare condition, occurring in approximately 1 in 10,000 to 1 in 150,000 live births. It affects males more frequently than females, with a male-to-female ratio of about 2:1. In nearly half of the cases, both feet are involved. The etiology of CVT is multifactorial. While some cases are idiopathic, many are associated with underlying neuromuscular or genetic disorders. Conditions such as arthrogryposis multiplex congenita, spina bifida, cerebral palsy, and chromosomal abnormalities like trisomy 13, 14, 15, or 18 are commonly linked to CVT.
A positive family history is present in up to 20% of cases, and mutations in genes such as HOXD10, which influence limb development, have been implicated. The deformity results from soft tissue contractures and abnormal muscle-tendon dynamics, where tendons like the peroneus longus and posterior tibialis function as dorsiflexors instead of plantar flexors.
Clinical Presentation
The hallmark of CVT is the rocker-bottom appearance of the foot, which is usually evident at birth. The midfoot is dorsiflexed, the hindfoot is elevated, and the forefoot is abducted. The talar head is prominent and palpable in the medial plantar arch. Unlike flexible flatfoot conditions, CVT is rigid and does not improve with stretching or bracing. As the child begins to walk, gait abnormalities become apparent, such as a “peg-leg” or calcaneal gait due to poor push-off power and limited forefoot contact.
Diagnosis
Early and accurate diagnosis is essential for effective treatment. Pediatric orthopedic specialists typically perform a thorough physical examination and assess the child’s gait and foot alignment. Radiographic imaging is crucial for confirming the diagnosis. Standard views include anteroposterior (AP), oblique, and lateral foot X-rays. A forced plantar flexion lateral radiograph is particularly diagnostic, revealing persistent dorsal dislocation of the talonavicular joint and a vertically oriented talus. Meary’s angle, which measures the alignment between the talus and the first metatarsal, is often greater than 20°, indicating significant deformity.
Differential Diagnosis
CVT must be distinguished from other congenital foot deformities, such as calcaneovalgus foot and clubfoot. Calcaneovalgus is a flexible deformity that typically resolves with time or minimal intervention, whereas CVT is rigid and requires surgical correction. Clubfoot presents with a different set of deformities, including plantarflexion and inversion of the foot, and is often misdiagnosed in cases of CVT by less experienced clinicians.
Treatment
The primary goal of treatment is to achieve a functional, stable, and pain-free foot. Management typically begins with non-surgical methods such as serial manipulation and casting, which aim to gradually correct the deformity. However, due to the rigidity of CVT, these methods are often insufficient on their own.
Definitive treatment usually involves surgical intervention between 6 to 12 months of age. The procedure includes soft tissue release, reduction of the talonavicular joint, and stabilization using pins. In some cases, tendon transfers or osteotomies may be required to correct severe deformities. Postoperative care involves immobilization and physical therapy to ensure proper healing and function.
Prognosis
With timely and appropriate treatment, most children with Congenital vertical talus can achieve good functional outcomes. Surgical correction typically results in improved foot alignment, mobility, and gait. However, long-term follow-up is necessary to monitor for recurrence or complications such as stiffness, pain, or residual deformity. Children with associated neuromuscular or genetic conditions may have more complex treatment courses and variable outcomes.
Congenital vertical talus is a rare but serious pediatric foot deformity that requires early recognition and intervention. Its association with systemic conditions underscores the importance of a comprehensive evaluation. Advances in diagnostic imaging and surgical techniques have significantly improved outcomes for affected children. Multidisciplinary care involving orthopedic surgeons, geneticists, and physical therapists is essential to ensure optimal treatment and long-term function. As awareness of Congenital vertical talus grows, so does the potential for timely diagnosis and effective management, offering children a better quality of life and mobility.