FOOT DEFORMITIES AND THEIR RELATIONSHIP WITH DEVELOPMENTAL DYSPLASIA OF THE HIP: AN 11 YEAR PROSPECTIVE LONGITUDINAL OBSERVATIONAL STUDY

Abstract

An 11 year prospective longitudinal study assessed the relationship between major neonatal foot deformities and developmental dysplasia of the hip (DDH). From 41,474 infants born between 01/01/1996 and 31/12/2006 with 614 foot deformities were referred as ‘risk factors’ in a screening/surveillance programme for DDH. All hips were clinically examined and sonographically imaged in a specialist Paediatric Orthopaedic clinic.

The 614 cases were subdivided into: 436 postural equinovarus deformities (TEV), 60 fixed congenital talipes equinovarus (CTEV), 93 congenital talipes calcaneovalgus (CTCV) & 25 metatarsus adductus. The overall risk of sonographic dysplasia/instability was as follows: TEV 1:27, CTEV 1:8.6, CTCV 1:5.2, Metatarsus adductus 1:25

The Relative Risk (RR) of sonographic dysplasia/instability in TEV vs CTEV was 0.31 (95% CI 0.12–0.80; p=0.0057; OR=0.29). The Relative Risk of dysplasia/instability in CTCV vs. Postural TEV is 5.27 (95% CI 2.57–10.8; p< 0.0001; OR=6.30).

The risk of Type IV hip instability or irreducible dislocation in CTCV was 1:15.4 (6.5%), 1:25 (4%) in metatarsus adductus and 1:436 (0.2%) in TEV. There were no cases of hip instability (Type IV) or irreducible dislocation in the CTEV cases.

The routine screening for DDH in cases of postural TEV and fixed CTEV is no longer advocated. Postural TEV is poorly defined as a deformity in the literature leading to the over diagnosis of a possibly spurious condition. Sonographic imaging and surveillance of the hips in cases of CTCV and metatarsus adductus should continue.