eMedicine Specialties > Orthopedic Surgery > Pediatrics

Congenital Vertical Talus

Author: Jeffrey D Thomson, MD, Assistant Professor, Department of Orthopedic Surgery, University of Connecticut; Director of Orthopedic Surgery, Department of Pediatric Orthopedic Surgery, Connecticut Children's Medical Center
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Updated: Mar 20, 2007

Introduction

Congenital vertical talus (CVT) is an uncommon disorder of the foot, manifested as a rigid rocker-bottom flatfoot. Its characteristic radiographic feature is a dorsal dislocation of the navicular on the talus. If left untreated, CVT results in a painful and rigid flatfoot with weak push-off power. CVT has been referred to in the literature by several synonyms, including congenital convex pes valgus.

History of the Procedure

Closed treatment, consisting of manipulation and casting, was the earliest form of treatment. Limited surgery was sometimes additionally employed.

Lamy and Weissman (1939) recommended excision of the talus, while Eyre-Brook (1967) advocated excising the navicular. Today, neither of these techniques is accepted as a definitive treatment.

Several authors, beginning with Osmond-Clarke (1956), Herndon and Heyman (1963), and Coleman and associates (1970), described staged, 2-incision reconstructive surgery. The first stage of the Coleman procedure consisted of lengthening the extensor digitorum longus (EDL), extensor hallucis longus (EHL), and tibialis anterior, with capsulotomies of the talonavicular and calcaneocuboid joints and release of the talocalcaneal interosseous ligament. The second stage consisted of tendo-Achilles lengthening (TAL) and a posterior capsulotomy of the ankle and subtalar joints.

After noting a high incidence of complications with the 2-stage technique, Ogata and colleagues (1979) recommended a single-stage procedure with a medial approach. Kodros and Dias (1999) published results they derived using a single-stage approach with a Cincinnati incision.

In 1987, Seimon described a single-stage dorsal approach in which the EHL and peroneus tertius were tenotomized and the talonavicular joint was opened. The talonavicular joint was reduced and held with a Kirschner (K) wire. The Achilles tendon was lengthened percutaneously. Stricker and Rosen (1997) published their experience with this technique, as did Mazzocca and associates (2001); both groups noted excellent results with few complications.

The trend toward less surgery for CVT continued with Dobbs and colleagues, who in 2006 published their technique of casting; percutaneous K-wire pinning of the talonavicular joint; and percutaneous heel-cord tenotomy. No patients had extensive soft-tissue releases, although some required lengthening of the anterior tibialis or the peroneus brevis tendon. Casting without pinning of the talonavicular joint was associated with recurrence of deformity.

Problem

CVT is defined by an irreducible and rigid dorsal dislocation of the navicular on the talus. If the navicular is reducible on the lateral maximum plantarflexion radiograph, it is deemed an oblique talus, which is better treated with TAL and orthotics.

Frequency

CVT is an uncommon disorder. In a 1983 literature review, Jacobsen and Crawford (1983) reported only 273 cases. Some have estimated the incidence of CVT to be one tenth that of congenital clubfoot.

Etiology

The etiology is unknown, but CVT frequently is associated with a wide variety of neuromuscular disorders. Ogata and associates proposed a CVT classification system that divides patients into 3 groups: idiopathic, genetic/syndromic, and neuromuscular.

Pathophysiology

The hallmark of the deformity is an irreducible and rigid dorsal dislocation of the navicular on the talus. Seimon hypothesized that a contracture of the tendo-Achilles posteriorly creates equinus of the calcaneus, with increased verticality of the talus, while contracture of the EDL (and sometimes the EHL and tibialis anterior) pulls the navicular onto the dorsum of the navicular.

Presentation

Clinically, CVT presents as a rigid flatfoot with a rocker-bottom appearance of the foot. The calcaneus is in fixed equinus, and the Achilles tendon is very tight. The hindfoot is in valgus, while the head of the talus is found medially in the sole, creating the rocker-bottom appearance. The forefoot is abducted and dorsiflexed.

The foot is stiff. In ambulatory children, calluses can develop under the head of the talus, which is very prominent along the plantar-medial foot.

Associated genetic syndromes must be excluded; therefore, a consultation with a pediatric geneticist may be indicated.

Indications

Surgery is indicated when the talonavicular joint is found, after a trial of serial casting, to be unreducible. Although most patients require surgical intervention, serial casting with the foot in plantarflexion may occasionally be successful. More importantly, serial casting helps to stretch out the contracted dorsal skin, tendons, and joint capsules, which should be helpful at the time of surgery. Lateral radiographs of the foot in maximal plantarflexion can reveal if the navicular is reducible.

Relevant Anatomy

A rigid, irreducible talonavicular dislocation is the hallmark of CVT. Contractures of the tendo-Achilles posteriorly and the EDL and dorsal talonavicular capsule anteriorly are common. In feet with greater involvement or in older children, more contractures and deformity are present (eg, contractures of the tibialis anterior and EHL anteriorly, peroneus tertius and inferior retinaculum of the ankle anterolaterally, peroneus brevis and longus laterally with the calcaneofibular ligament, and the tibiotalar joint posteriorly).

Coleman divided CVT into 2 types: type 1 was associated with a calcaneocuboid dislocation, and type 2 was not. This distinction is important clinically because the type 1 deformity is stiffer and particular attention must be paid to releasing the calcaneocuboid joint.

Contraindications

If the talonavicular joint is reducible on the lateral maximum plantarflexion view radiograph, surgery is probably not needed. In these cases, TAL and orthotics, such as a University of California Berkeley Laboratory (UCBL) orthosis, may be effective.

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