An Unusual Cause of Talipes Equinovarus: Agenesis of Leg Muscles
On physical examination, talipes equinovarus of the right foot was found associated with remarkable hypoplasia of the anterior and posterior aspects of the right leg. The rest of the physical examination result, especially neurological, was without abnormalities; and we did not find any associated deformations or malformations of the musculoskeletal system.
An ultrasonographic examination had shown agenesis of the muscles of the anterior aspect and the triceps surae. These findings were confirmed by magnetic resonance imaging, which had also shown a normal aspect of the Achilles tendon and leg bones and especially no asymmetry of length (Fig. 1).
Electromyographic examination showed motor and sensory denervation of both the tibial nerve and the common peroneal nerve, more severe for the latter. Cerebromedullar magnetic resonance imaging and Doppler examination of the leg had not shown any abnormalities. Karyotype was normal. The child was managed according to the Ponseti method, which consists in a gradual correction of the foot deformities using a serial of casts.
Muscle abnormalities including aberrant muscles, unusual origin or insertion, and congenital absence or aplasia are reported to have an incidence of 1:11,000.1
Congenital muscle agenesis is considered to be a rare cause of talipes equinovarus. To the best of our knowledge, it is the second reported case.2 We found clinically evident anomalies with a neurological deficit of both the internal and external sciatic nerves.
In cases of talipes equinovarus with muscle agenesis, the treatment is usually based on tendons transfer surgery.3 In our case, this approach was impossible owing to the lack of functional muscles, so we opted for an orthopedic treatment according to the Ponseti method followed by an active rehabilitation.