Clubfoot Deformity (Talipes Equinovarus)

CLUBFOOT DEFORMITY (TALIPES EQUINOVARUS)

Clubfoot is the most common congenital abnormality of the ankle and foot. Prevalence: 1 per 1000 live births.

Clubfoot is a combination of 4 deformities:

Hindfoot equinus (reversed calcaneal pitch).
Hindfoot varus (inward rotation; talocalcaneal angle of almost zero on AP view with bones parallel to each other).
Forefoot adductus (axis of first metacarpal deviated medially relative to axis of talus).
Variable forefoot cavus (plantar flexion).

Clinical classification (1):

Postural talipes – talipes that will correct with the normal growth of the child.
Moderate talipes – talipes that requires conservative measures to correct, but may require surgical intervention.
Severe talipes – talipes that does not respond to conservative measures and may be resistant to surgical intervention.

The feet are often classified retrospectively and no study has investigated the reliability of trying to classify them antenatally.

Diagnosis is based on demonstrating the tibia and fibula in the same plane as the lateral aspect of the foot, with the foot extended and inverted.
Persistent (true clubfoot), transient (fetus can transiently turn foot into a position that simulates clubfoot) or relapsing (resolves in one scan and recurs in follow-up scans).
Unilateral or bilateral.
Classifies as postural, idiopathic or complex (other anomalies present which may not always be evident on antenatal scanning).
The gestational age at which the etiology, rather than the diagnosis of the talipes, is confirmed is extremely important:

Most complex cases (75%) are diagnosed at the 18-23 week scan (2).
The remainder were diagnosed when the classification was changed from idiopathic to complex, either when scanned again after 24 weeks gestation (19%) or postnatally (6%).
In this study 68 of the cases of talipes thought to be idiopathic at the 18-23 week scan, 13(19%) were subsequently found to be complex. This is important for counseling parents.

Scan at 16-18 weeks does not exclude the diagnosis as late onset of clubfoot does occur.
Jeanty and co-workers (3) describe two criteria for the diagnosis:

Anteversion of the foot.
Metatarsal rays are seen in the same plane, a medial to lateral plane that passes through the tibia and fibula and is perpendicular to the tibia and fibula.

Rounded angle between the foot and lower leg (this sign may, however, be seen transiently in normal fetuses and is thus not pathognomonic).
Tibia/fibula and foot (including toes) can be demonstrated simultaneously in their long axis i.e. foot deviates medially and lies at right angles to the tibia and fibula.
Foot visualized in a plane perpendicular to the lower leg and not perpendicular to it.
Foot must not be in an inverted position due to the confines of the uterus and is best diagnosed when the foot is completely surrounded by amniotic fluid.
This position must be maintained for 10-30 minutes, as clubfoot may be transient. Follow up scans should probably be obtained in all cases. This excludes the false positive diagnosis of clubfoot.

Unilateral isolated clubfoot

Maffulli N. Opinion: Prenatal ultrasonographic diagnosis of talipes equinovarus: does it give the full picture? Ultrasound Obstet Gynecol 2002;20:217-218.
Bakalis S, Sairam S, Homfray T et.al. Outcome of antenatally diagnosed talipes equinovarus in an unselected obstetric population. Ultrasound Obstet Gynecol 2002;20:226-229.
Jeanty P, Romero R, d'Alton M et.al. In utero sonographic detection of hand and foot deformities. J Ultrasound Med 1985;4(11):595-601.

Unilateral isolated clubfoot