[Congenital convex talus. Methods and results of a single-stage surgical correction]

The aim of this study was to emphasize the anatomical particularities of congenital vertical talus. We propose a one stage operative procedure adapted to the deformities.

A retrospective study of 24 children with congenital vertical talus was conducted. An etiology was observed in 58 per cent of cases and 42 per cent were considered as idiopathic. From a radiological analysis of 39 feet, we precise the anatomical particularities. We used anteroposterior and lateral X-ray and lateral stress views with maximal plantar and dorsal flexion. Most of the lesions were localized in the midtarsal joint. The irreducibility of the talonavicular dislocation is the predominant lesion. It is usually associated with a disorientation of the cubocalcaneal joint. The articular surfaces are disorganized with a dorsal orientation. There is a variable amount of equinus deformity in the hindfoot. However the talocalcaneal divergence angle is nearly normal. The forefoot is most of the times in eversion but sometimes in inversion.

All children were treated initially by physiotherapy. We recommend operative treatment for them between one to two years old. After a soft tissue release, the talonavicular dislocation and the hind foot equinus deformity is reduced simultaneously. The subtalar joint is respected and not opened. Retracted tendons may be an obstacle to the reduction. They must be lengthened if necessary especially the Achilles tendon, the peronei, the extensors and the tibialis anterior. Reduction is maintained by a K wire transfixing the midtarsal joint.

Clinical results were difficult to evaluate. Out of 24 operated feet, a satisfactory outcome had been achieved in 15 feet. All were plantigrad and 18 had a good cosmetically aspect. The only bad result concerned an old case which was not operated by this technique.

Conservative treatment is usually unsuccessful in congenital vertical talus. Numerous procedures have been advocated for the surgical correction of this deformity. Some authors advised excision of the navicular, full open peritalar release or extraarticular talocalcaneal arthrodesis. These are often extensive procedures and most are performed in two stages. Recently, one stage operative procedure was proposed. It allows a good correction with the respect of the subtalar joint and a lower risk of talus avascular necrosis. Furthermore it is more adapted to the deformity with a less extensive scar and a better respect of the anatomy.