Aim The relationship between the presence and severity of sonographically diagnosed developmental dysplasia of the hip (DDH) and the clinical abnormality of limitation of hip abduction (LHA) was investigated.

Methods A prospective, longitudinal, selective ‘at risk’ and neonatal instability hip ultrasound programme between 1 January 1996 and 31 December 2005. 2876 neonates/infants were initially screened for DDH by clinical examination and by hip ultrasound imaging. Pathological sonographically evaluated DDH was considered to be Graf Type III, IV and irreducible hip dislocation. Inclusion criteria were cases of unilateral or bilateral limitation of hip abduction hip. Exclusion criteria: syndromal, neuromuscular and skeletal dysplasia cases.

Results 492 children presented with LHA (55 unilateral LHA). The mean age of neonates/infants with either unilateral or bilateral LHA was significantly higher than those without (p<0.001). In the sonographic diagnosis of Graf Type III and IV dysplasias, unilateral LHA had a PPV of 40% compared with only 0.3% for bilateral LHA. The sensitivity of unilateral LHA increased to 78.3% and a PPV 54.7% after the age of 8 weeks for Graf Types III, IV and irreducible hip dislocation.

Conclusions This study identifies a time-dependent association with unilateral LHA in the diagnosis of ‘pathological’ DDH after the age of 8 weeks. The presence of bilateral LHA in the young infant may be a normal variant and is an inaccurate clinical sign in the diagnosis of pathological DDH. LHA should be actively sought after 8 weeks of age and if present should be followed by a formal ultrasound or radiographic examination to confirm whether or not the hip is developing in a satisfactory manner.