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Children's OrthopaedicsFurther Opinion

The association between clubfoot and developmental dysplasia of the hip

DC Perry, SM Tawfiq, A Roche, R Shariff, NK Garg, LA James, J Sampath, CE Bruce

J Bone Joint Surg [Br] 2010;92-B:1586-8.

 

Controversy persists in the recent literature as to a potential association between idiopathic structural congenital talipes equinovarus (CTEV) foot deformity of the newborn and developmental dysplasia of the hip (DDH). Although many experienced paediatric orthopaedic surgeons believed such a link existed, more recent studies1-3 have challenged that view. This paper returns to add support to the view that a link does indeed exist.

There appear to be two linked, but subtly different questions being asked; firstly, whether for any given newborn with idiopathic CTEV, does he/she have an increased risk of DDH, and secondly whether sufficient association exists to include structural CTEV on a list of risk factors in drawing up a population screening programme for DDH?

Before examining these questions in turn, the reader must ensure that each paper clearly defines how the two diagnoses (of idiopathic CTEV and DDH) are made, and in the particular case of DDH, whether the baby needs intervention. Any previous diagnostic difficulty regarding the definition of structural (as opposed to postural) CTEV or indeed differentiating the condition from other neonatal foot conditions appears to be disappearing – perhaps with the resurgence in non-operative methods of CTEV management, including the Ponseti method.4 Structural CTEV can now be simply defined as a foot deformity of the newborn, which includes midfoot cavus, forefoot adductus, hindfoot varus and ankle equinus, when these deformities are not fully passively correctable. This paper, in common with most of the available literature, only addresses idiopathic CTEV, ruling out cases with known or suspected syndromes or underlying neuromuscular conditions.

When reviewing the relevant literature on DDH, the reader must not only be aware of the method of diagnosis (clinical, ultrasound or radiograph), but perhaps more importantly whether the baby requires active management (a decision usually based on the severity of the condition and the age of the baby). Whilst some earlier papers1,2 used radiographs, most papers use ultrasound and in particular follow the method popularised by Graf.5 Using this classification, most authors would agree Graf I hips are normal and do not require treating, and Graf III and IV hips do require intervention.  There remains no consensus as to the treatment of Graf II hips, in particular the Graf IIb group.

Armed with the above, the reader can look for relevant rates of associations in a representative sample of the literature:

Wynne Davis (1982)1  used the Edinburgh Register of the Newborn 1964-1968 and identified just one baby in 165 had both idiopathic CTEV and DDH (called congenital dislocation of the hip in the paper), diagnosed presumably by X-ray. This was from a cohort of 33 with idiopathic CTEV giving an incidence of 1 in 33 (3%).

Westberry et al2  looked at a population of 349 babies with idiopathic CTEV. 127 had screening hip radiographs identifying 1 with hip dysplasia. 1 in 127 (0.7%).

Carney and VanekX-rayed 51 children with CTEV and found 8 had an acetabular index of over 28 degrees. 8 in 51 or 1 in 6.4 (16%)

Paton et al have published several excellent papers3,7,8 looking at their large experience of clinical and ultrasound screening for DDH.  Their first paper found of 140 babies referred to the screening programme with ‘foot abnormalities’, 1 had a dislocation. 1 in 140 (7%). Later figures showed 427 babies referred with ‘foot deformity’ of whom 13 had either dislocation or type 3 dysplasia. 13 in 427 or 1 in 32 (3%). In 2009 the group looked specifically at neonatal foot deformities and their relationship to DDH. Of 614 total foot deformities, 60 had idiopathic structural CTEV. Of these, 7 had Type II dysplasia but none had Type III or Type IV. In total 7 in 60 or 1 in 8.6 (12%), but for Type II or IV dysplasia 0 in 60 (0%).

This paper by Perry et al looked at 119 babies with idiopathic structural CTEV. They found 33 had evidence of DDH on ultrasound screening; 26 Type IIa, 3 Type IIb, 3 type III and 1 type IV. Even if one excludes Type IIa cases this gives 7 in 119 or 1 in 17 (6%).

These various figures should be set in the context of the incidence of DDH in the population at large. Weinsteinquotes 72 cases diagnosed clinically confirmed on X ray out of 51359 live births 72 in 51359 or 1 in 713 (0.14%). Paton (1999) found the rate of instability diagnosed on ultrasound scan to be 2.2 per 1000 live births 2.2 per 1000 or 1 in 454 (0.22%).

Where does all of the above leave the (potentially confused) reader? Once the details of how the diagnosis of CTEV has been made and more importantly not only how the diagnosis of DDH has been made, but the degree of dysplasia and the controversy of which babies actually need to be treated, the reader must draw their own conclusions from these (and other similar) studies, including this most recent addition. Also, we should not forget that from the babies’ perspective, an ultrasound examination of the hips is a quick and painless procedure without known side effects.

In personal answer to my initial two questions; firstly, for any given newborn who has a diagnosis of structural idiopathic CTEV made, I will advise the parents to have a screening ultrasound scan for DDH. Secondly, structural idiopathic CTEV remains on the list of risk factors for inclusion in the DDH screening programme in our region. 

References

1. Wynne-Davies R, et al. Aetiology and interrelationship of some common skeletal deformities. J Med Gen 1982;19:321-8.
2. Westberry DE, Davids JR, Pugh LI. Clubfoot and developmental dysplasia of the hip: value of screening hip radiographs in children with clubfoot. J Paediatr Orthop 2003;23:503-7.
3. Paton RW, Choudry Q. Neonatal foot deformities and their relationship to developmental dysplasia of the hip: a ten-year prospective study. J Bone Joint Surg [Br] 2009;91-B:655-8.
4. Ponseti IV. Congenital Clubfoot; fundamentals of treatment. Oxford: Oxford University press, 1996.
5. Graf R, Tschauner Chr, Klapsch W. Progress in prevention of late developmental dislocation of the hip by sonographic newborn hip ‘screening’: results of a comparative follow up study. J Pediatr Orthop [B] 1993;2:115-21.
6. Carney BT, Vanek EA. Incidence of hip dysplasia in idiopathic clubfoot. J Surg Orthop Adv 2006;15:71-3.
7. Paton RW, Srinivasan MS, Shah B, Hollis S. Ultrasound screening for hips at risk in developmental dysplasia. Is it worth it? J Bone Joint Surg [Br] 1999;81-B:255-8.
8. Paton RW, Hinduja K, Thomas CD. The significance of at-risk factors in ultrasound surveillance of developmental dysplasia of the hip: a ten-year prospective study. J Bone Joint Surg [Br] 2005;87-B:1264-6.
9. Weinstein SL. Natural history of congenital hip dislocation (CDH) and hip dysplasia. Clin Orthop 1987;225:62-76.

 

Atherton WG, MA, FRCS (Tr & Orth)

Department of Orthopaedics, Bristol Royal Hospital for Children, Bristol, United Kingdom

E-mail: guy.atherton@UHBristol.nhs.uk