Congenital abnormalities of the foot. Congenital clubfoot. Congenital flatfoot (vertical talus)
Congenital clubfoot (Talipes Equinovarus aka Equinovarus)
Incidence is around 1:1000, most cases are sporadic, however there are some AD cases, it is bilaterally in about 50% of patients, in such patients both feet are generally of the same severity. The underlying cause is unknown, the best theory is that of a primary germplasm defect in the talus causes continued plantarflexion and inversion of the bone with subsequent soft-tissue changes.
There are four basic components in clubfoot, these are:
- Cavus (fixed plantar flexion/a high arch)
- Adduction (foot moves inwards)
- Varus (foot points inwards (medial angulation of distal foot)
- Equinus (upward bending motion of the ankle joint lis limited, with sole permanently flexed so walking is on the toes)
The diagram below shows the pathological process nicely, but it can be summed up as the following steps:
- Neck of the talus is deviated downwards, while the body is rotated outwards
- The downwards deviation of the talus causes calcaneal pivoting, with the distal part moving laterally and the proximal part moving laterally
- The navicular and forefoot are then forced into a rotational shift and supinated
The underlying cause of the deformity is thought to be the talonavicular joint, the tibialis posterior, gastrocnemius and soleus all insert on onto the navicular or calcaneal bones and are shortened in club foot, despite being normal in all other ways. This deviation causes malalignment of the talus, causing the remaining deformities.
Treatment in youngsters is that of the Ponseti method, with sequential gentle manipulation and splinting of the foot with serial casts for a long time starting as soon after birth as possible. Achilles lengthening is often also required to achieve a plantigrade foot and braces may be required up to the age of 4. If conservative treatment is not successful, then an operation to lengthen the structures on the medial side of the foot and calf as well as release the posterior capsule of the ankle joint will need to be done on a number of occasions to account for the growth of the child.
If the foots position is still unsatisfactory, a triple arthrodesis will be required to fuse together the calcaneocuboid, subtalar and talonavicular joints.