Talipes equinovarus

Sir

I read with interest the article entitled `Clinical outcome of congenital talipes equinovarus diagnosed antenatally by ultrasound" in the August 2000 issue.

It is well known that congenital talipes equinovarus (CTEV) represents a spectrum, from so-called postural talipes requiring little active management, to a severe deformity requiring extensive surgery. Assessment of severity, even after birth, remains difficult, with some authors classifying the condition on the basis of a response to a period of conservative management.3

Without accurate assessment of severity, the natural history of the condition and the management required cannot be predicted. Indeed, 26% of those diagnosed antenatally by Tillett et al as having CTEV required no active management. These are presumably children with postural talipes as described by Porter, or even transient talipes as described by Bar-Hava et al. Given the high percentage of children requiring no treatment, it is difficult to justify the authors' statement that "when the appearances (on the antenatal scan) are abnormal, a significant abnormality is likely to be present". Other studies report a false-positive rate of up to 35%.5

The value of an antenatal diagnosis of talipes is in the fact that it may be associated with other genetic and morphological abnormalities and its presence therefore indicates the need for a detailed scan and karyotyping. Benacerraf7 found associated abnormalities in 15 of 18 fetuses with talipes diagnosed antenatally.

CTEV is a condition with a number of different causes which result in deformities of variable severity. For example, Macnicol and Nadeem have identified a subgroup of children with abnormalities of the somatosensory evoked potentials. Aetiological information of this type may ultimately prove to be of more value in predicting the natural history. Perhaps only when the aetiology of CTEV has been elucidated will it be possible to make a prediction of the natural history of the condition.

D. CHESNEY, FRCS Ed

Inverurie, Aberdeenshire. UK.

1. Tillett RL, Fisk NM, Murphy M, Hunt DM. Clinical outcome of congenital talipes equinovarus diagnosed antenatally by ultrasound. J Bone Joint Surg [Br] 2000;82-B:876-80.

2. Porter RW. Congenital talipes equinovarus: I. Resolving and resistant deformities. J Bone Joint Surg [Br] 1987;69-13:822-5.

3. Hooker CH. A clubfoot philosophy. J Bone Joint Surg [Br] 1985;67-B:490.

4. Bar-Hava I, Bronshtein M, Orvieto R, et al. Caution: prenatal clubfoot can be both a transient and a late-onset phenomenon. Prenat Diagn 1997;17:457-60.

5. Woodrow N, Tran T, Umstad M, et al. Mid-trimester ultrasound diagnosis of isolated talipes equinovarus: accuracy and outcome for infants. Aust N Z J Obstet Gynaecol 1998;38:301-5.

6. Gonzalez P, Nicolini U, Rahman F, Fisk NM, Rodeck CH. Does oligohydramnios cause fetal club foot? J Obstet Gynaecol 1991;11: 11-4.

7. Benacerraf BR. Antenatal sonographic diagnosis of congenital clubfoot: a possible indication for amniocentesis. J Clin Ultrasound 1986;14:703-6.

8. Macnicol NF, Nadeen RD. Evaluation of the deformity in club foot by somatosensory evoked potentials. J Bone Joint Surg [Br] 2000;82-B:731-5.

Authors' reply:

Sir,

We thank Mr Chesney for his comments on our paper. We agree that the severity of talipes is difficult to assess. Our point is that it is not possible to do this using antenatal ultrasound. Our statement that an abnormality detected on ultrasound correlates with talipes present at birth, was to stress that the purpose of this study was to help orthopaedic surgeons to counsel parents on whether or not their child has talipes and the likelihood of their baby needing treatment. We therefore stand by our statement, since these children all had talipes, although some cases were mild and needed only simple stretching. These were not normal feet, although they may well have been resolving postural talipes. It is important that surgeons are aware of these conditions when advising parents.

It is helpful to be able to tell parents that their child has a 26% chance of requiring only the simplest treatment and that the outcome will be excellent both functionally and cosmetically. The false-positive result described in our series was also important since it was part of a more complex deformity. We accept that other series have high false-positive rates but believe that these will reduce as antenatal scanning becomes more accurate.

Our paper was concerned only with the correlation between antenatal ultrasound and clinical outcome and not with the aetiology or natural history of talipes itself.

D. HUNT, FRCS

R. TILLETT, MB, BS

St Mary's Hospital

London, UK.

Copyright British Editorial Society of Bone & Joint Surgery Apr 2001
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