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Clubfoot

Unilateral clubfoot deformity. Both the tibia and fibula are seen on the same image as the medially deviated foot

Findings:

A unilateral clubfoot is identified. Normally when the tibia and fibula are seen together on the same sonographic image, a short axis view of the foot and ankle will be noted. In this case, the tibia and fibula as well as a full view of the foot.

Discussion:

Clubfoot abnormality is the most common musculoskeletal abnormality with a prevalence of 0.5 to 5 per 1000 births. The term clubfoot is a general descriptive term that describes three distinct abnormalities: talipes equinovarus (adduction of the forefoot, inversion of the heel and plantar flexion of the forefoot and ankle), talipes calcaneovalgus (dorsal flexion of the forefoot with the plantar surface facing laterally) and metatarsus varus (inversion and adduction of the forefoot alone). It may either be unilateral or bilateral.

From: Sucheston ME, Cannon MS eds. Congenital Malformations. Philadelphia, FA Davis Co., 1973

The mode of inheritance is thought to be multifactorial. Since many cases of clubfoot are familial a genetic factor appears to contribute to its development. It is more common in males than in females. Interestingly, females, although less commonly affected, have a greater proportion of relatives with clubfoot abnormality compared to males. If the parents are normal and if the family already has one affected male child, the risk of another child with clubfoot is 2-3 percent, if the child affected is female, the chance of having a sibling with clubfoot is 5%. If a parent is affected the risk of having an affected child is 15-25%. A twin study demonstrated that in 13 of 40 (33 per cent) monozygotic twins, each twin had a clubfoot as opposed to four of 134 (3 %) dizygotic twins. Certain racial groups appear to have an increased incidence of clubfoot. In Hawaii, the incidence of clubfoot among Hawaiians (6.8 per 1000 live births) is much higher than among Caucasians (1.12 per 1000 live births. Other studies have corroborated the increased incidence of clubfoot in Polynesians as well as populations of the Middle East and the Mediterranean coast of North Africa. Clubfoot is more common in males than females by a ratio 2.5 to 1. Approximately 55 per cent of cases are bilateral, and clinical reports suggest that bilateral deformities may be more resistant to therapy than unilateral deformities.

Although clubfoot may be an isolated entity, it is commonly associated with syndromes characterized by multiple congenital anomalies. A report by Yamamoto et al found a 10.3% incidence of other associated malformations. Clubfoot may also be associated with other malformations such as cleft lip and palate, micrognathia, congenital heart disease, hip dislocation and inguinal hernia. Clubfoot may be part of a systemic musculoskeletal disorder, a genetic syndrome, or associated with a neural tube abnormality. Musculoskeletal syndromes that have involved clubfoot include arthrogryposis, nail-patella syndrome, congenital constrictive bands, muscular dystrophies, diastrophic dwarfism, and lead poisoning. Clubfoot is also associated with hand abnormalities such as supernumerary fingers. Neurologic problems associated with clubfoot include spina bifida/meningomyelocele and hydrocephalus. Syndromes associated with clubfoot may be inherited as autosomal recessive such as Larsen syndrome or autosomal dominant, such as Gordon syndrome (camptodactyly, cleft palate, clubfoot) and distal arthrogryposis. Other conditions such as Pierre Robin syndrome have an X-linked recessive mode of inheritance.

The sonographic diagnosis of clubfoot should be made with the transducer positioned so that the tibia and fibula are simultaneously seen in their long axis, i.e., as on an anteroposterior radiograph. In this position, the ankle and foot normally are seen in short axis. However, in clubfoot the foot deviates medially and lies at a right angle to the tibia and fibula. This position should be constant in subsequent examinations. Unfortunately, there is a potential for a false-positive diagnosis. In a report by Hashimoto et al in a proven false-positive case on three separate occasions the foot appeared to be in a clubfoot position, however was normal at birth. In most instances one would expect that a fetus could temporarily turn the foot into a position simulating clubfoot, but that the aberrant positioning would readjust with time.

Bilateral clubfoot - Right and-

Left clubfoot

Even if the clubfoot is the only anomaly present in a fetus, fetal diagnosis allows time for prenatal parental counseling about the therapeutic consequences of clubfoot. Generally, orthopedic surgeons recommend early manipulation and casting of the foot. One orthopedic maxim that reflects this attitude is "in a breech delivery the clubfoot cast should be on the foot before the head is delivered." Therefore, by the time the child is born the parent s will be familiar with a therapeutic plan. Initially, surgeons may try a non-operative therapeutic approach involving manipulation by casting. Series reporting non-operative cures range from 19 to 90 per cent (mean of 50%). If the foot does not respond to these methods or if the deformity recurs after therapy, operative approaches may be required.

As was mentioned above, clubfoot may be associated with other abnormalities or syndromes. It may however occur in isolation. When isolated, a commonly raised issue is whether amniocentesis is warranted. It is known that there is an increased incidence of chromosomal abnormalities, as high as 22% in one series. These include:4p and l8q, as well as trisomy 13,18 and 21. Two recent studies have examined the implications of isolated clubfoot. A study by Shipp and Benacerraf retrospectively reviewed their database of sonographic reports over an 18 year period for the sonographic finding of a clubfoot abnormality. Fetuses with associated anomalies were excluded from the study. Their final analysis was of those in which follow-up was obtained. From an initial group of 87 fetuses with isolated clubfoot abnormality, 68 had follow-up. 38 fetuses had bilateral clubfoot verified after birth with correct prenatal sonographic identification. 15 fetuses had unilateral clubfoot after birth, correctly identified prenatally. 5 infants had unilateral clubfoot at birth, although prenatally they were thought to have bilateral clubfeet and 2 infants had bilateral clubfeet at birth but were thought to have unilateral clubfoot prenatally. 8 fetuses were thought to have clubfoot abnormality but were normal at birth (5 of 8 done in the 3rd trimester). Thirty four of 68 fetuses had karyotyping of which 4 were abnormal (47, XXY, 47, XXX, trisomy 21, trisomy 18). (4 of 68 or 5.9%). The non-karyotyped fetuses appeared normal morphologically at birth. At birth the two trisomic fetuses were found to have: (trisomy 21) early renal dysplasia and (trisomy 18) 2 vessel cord and clenched fists). The authors conclude that karyotyping is indicated when an isolated clubfoot abnormality is identified. This is based upon the fact that there was a significantly higher association with chromosomal abnormality when this finding was seen than maternal age alone as a factor and that other more subtle associated findings may be missed. They also cautioned that scans done in the late 1st or early 2nd trimester may miss subtle findings and that more false positive exams may be noted in the 3rd trimester when position may simulate this appearance. The false positive rate was 11.8% (19% if the false-positive bilateral clubfeet are added), which is high, and should be taken into consideration. It should also be noted that the two trisomic cases were somewhat atypical in that the "usual" associated anomalies, such as cardiac abnormalities often seen in trisomy 18, were not identified in these two cases.

In another study this year by Rijhsinghani et al, the authors retrospectively reviewed their sonographic database of 23, 863 patients between 1989 and 1996 for cases of clubfoot abnormality. Their analysis revealed club foot abnormality in 35 cases from 17.4 to 37 weeks gestation. 28 of 35 cases were referred due to abnormal sonographic findings elsewhere. Interestingly, in only 7 of these cases was club foot abnormality diagnosed. Eighteen cases were unilateral and 17 were bilateral. Seventeen of the cases were diagnosed prior to 24 weeks. Seven cases were categorized as isolated club foot. On follow-up 2 of these 7 had arthrogryposis at neonatal evaluation, one had cerebral atrophy and cerebral palsy at neonatal follow-up and one was normal at follow-up ultrasound scan. The remaining 3 cases had no other abnormalities detected postnatally. Of interest, all 3 had a family history that included club foot abnormality. Additional abnormalities were found in 28 of 35 patients (neural tube=14, hydrocephalus, ventriculomegaly, cardiac defects and diaphragmatic hernia). Five of the 28 fetuses with multiple anomalies had karyotype abnormalities (trisomy 18 in 4 and 46XY,-3,+der(3)t(3;6) in the other case. Two cases had a false-positive diagnosis of club foot abnormality, one of which was isolated, other seen with other abnormalities. No case of bilateral club foot abnormality had a false positive diagnosis. This is an interesting study that reconfirms the strong association of club foot abnormality with other malformations. The difficulty with this study is the referral nature of the patients. The authors advise careful evaluation for movement disorders if club foot is detected. This is certainly reasonable. They also advise "strong consideration of karyotype evaluation" when club foot is diagnosed. In this study, this would be reasonable if other malformations were detected however, no karyotypic abnormalities were seen when the clubfoot was isolated.

A recent retrospective study of 103,228 pregnancies by Bakalis et al also investigated the association of clubfoot abnormalities to other anomlies and outcome. The incidence of fetal talipes following routine ultrasound examination between 18 and 23 weeks in their study was 0.10% (107/103,228) and was bilateral in 64 (59.8%) and unilateral in 43 (40.2%) cases. In 52 (48.6%) cases, talipes was of complex etiology, as it was associated with other defects, while, in 55 (51.4%) cases, it was classified as idiopathic. Of these 52 patients there were: 20 neurological, 20 genetic, nine chromosomal and three musculoskeletal syndromes. There were no chromosomal abnormalities in the group classified as idiopathic talipes equinovarus on ultrasound. In 19% of cases, an initial diagnosis of idiopathic talipes was changed to complex, because of the subsequent development of associated features. The majority of complex cases diagnosed late were progressive neurological or musculoskeletal conditions. Perinatal death and long-term neurodevelopmental or musculoskeletal problems were significantly more common when the talipes was complex rather than idiopathic (odds ratio, 150; 95% confidence interval, 34,665). Adverse outcomes were also seen more frequently with bilateral compared to unilateral talipes (odds ratio, 3.44; 95% confidence interval, 1.50-7.90).  The authors, conclusion: "The outcome of antenatally detected talipes is mainly dependent on the presence or absence of other defects. A significant proportion of cases, thought to be idiopathic at presentation, will develop associated complex features when reassessed on subsequent scans or postnatally."

It should also be remembered that in addition to genetic factors, there are extrinsic causes of clubfoot deformity, including severe oligohydramnios and constriction in the uterus as well as amniotic bands.

References:

Hashimoto BE, Filly RA, Callen PW Sonographic diagnosis of clubfoot in utero. J Ultrasound Med 5:81-83, 1985

Bromley B, Benacerraf B. Abnormalities of the hands and feet in the fetus: sonographic findings. Amer J Roentgenol 165:1239-1243, 1995

Yamamoto H. A clinical genetic and epidemiologic study of congenital clubfoot. J Human Genet 24:37-44, 1979

Bronshtein M, Zimmer EZ. Transvaginal ultrasound diagnosis of fetal clubfeet at 13 weeks, menstrual age. J Clin Ultrasound 17:518-520, 1989

Benacerraf BR, Frigoletto FD. Prenatal ultrasound diagnosis of clubfoot. Radiology 155:211-213, 1985

Lehman WB: The Clubfoot. Philadelphia, J.B. Lippincott, 1980

Chervenak FA, Tortora M, Hobbins JC: Antenatal sonographic diagnosis of clubfoot.J Ultrasound Med 4:49, 1985

Palmer RM: The genetics of talipes equinovarus. J Bone Joint Surg (Am) 46A:542, 1964

Turco VJ: Clubfoot. New York, Churchill-Livingstone, 1981

Palmer RM, Conneally PM, Pao-Le Y: Studies of the inheritance of idiopathic talipes equinovarus. Orthop Clin North Am 5:99, 1974

Wynne-Davies R: Family studies and the cause of congenital clubfoot. J Bone Joint Surg (Br) 4613:445, 1964

Idelberger K: Die ergebnisse der zwillingsforschung beim angeborenen klumpfuss. Verhandlungen der Deutschen Orthopadischen Gesellschaft 33:272, 1939; as quoted by Wynne-Davies R.: Family studies and the cause of congenital clubfoot. J Bone Joint Surg (Br) 4613:445, 1964

Chung CS, Nemecheck RW, Larsen J, et al: Genetic and epidemiological studies of clubfoot in Hawaii. Human Hered 19:321, 1969

LeNoir JL: Congenital Idiopathic Talipes. Springfield, Illinois, Charles C Thomas, 1966

Ferguson AB: Orthopaedic Surgery in Infancy and Childhood. Baltimore, Williams and Wilkins, 1981

Jahss MH: Disorders of the Foot, Vol. 1. Philadelphia, W.B. Saunders, 1982

Shipp TD, Benacerraf BR. The significance of prenatally identified isolated clubfoot: Is amniocentesis indicated? Am J Obstet Gynecol 178:600-2, 1998

Rijhsinghani A, Yankowitz J, Kanis AB, Mueller GM, Yankowitz DK, Williamson RA. Antenatal sonographic diagnosis of club foot with particular attention to the implications and outcomes of isolated club foot ultrasound. Obstet Gynecol 12:103-106, 1998

Bakalis S, Sairam S, Homfray, Harrington K, Nicolaides K, Thilaganathan B. Outcome of Antenatally Diagnosed Talipes Equinovarus in an Unselected Obstetric Population Ultrasound Obstet Gynecol 20:226, 2002

 

 

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Peter W. Callen, M.D.
Professor of Radiology, Obstetrics, Gynecology and Reproductive Science
University of California Medical Center, San Francisco, California