Despite the presence of screening programmes, infants continue
to present with late developmental dysplasia of the hip (DDH), the
impact of which is significant. The aim of this study was to assess
infants with late presenting dislocation of the hip despite universal
clinical neonatal and selective ultrasound screening. Between 01 January 1997 to 31 December 2011, a prospective, longitudinal
study was undertaken of a cohort of 64 670 live births. Late presenting
dislocation was defined as presentation after three months of age.
Diagnosis was confirmed by ultrasound and plain radiography. Patient
demographics, referral type, reason for referral, risk factors (breech
presentation/strong family history) and clinical and radiological
findings were recorded.Aims
Patients and Methods
Over a 15-year prospective period, 201 infants
with a clinically unstable hip at neonatal screening were subsequently
reviewed in a ‘one stop’ clinic where they were assessed clinically
and sonographically. Their mean age was 1.62 weeks (95% confidence
interval (CI) 1.35 to 1.89). Clinical neonatal hip screening revealed
a sensitivity of 62% (mean, 62.6 95%CI 50.9 to 74.3), specificity
of 99.8% (mean, 99.8, 95% CI 99.7 to 99.8) and positive predictive value
(PPV) of 24% (mean, 26.2, 95% CI 19.3 to 33.0). Static and dynamic
sonography for Graf type IV dysplastic hips had a 15-year sensitivity
of 77% (mean, 75.8 95% CI 66.9 to 84.6), specificity of 99.8% (mean,
99.8, 95% CI 99.8 to 99.8) and a PPV of 49% (mean, 55.1, 95% CI
41.6 to 68.5). There were 36 infants with an irreducible dislocation
of the hip (0.57 per 1000 live births), including six that failed
to resolve with neonatal splintage. Most clinically unstable hips referred to a specialist clinic
are female and stabilise spontaneously. Most irreducible dislocations
are not identified from this neonatal instability group. There may
be a small subgroup of females with instability of the hip which
may be at risk of progression to irreducibility despite early treatment
in a Pavlik harness. A controlled study is required to assess the value of neonatal
clinical screening programmes. Cite this article:
Since September 1964, neonates born in New Plymouth have undergone clinical examination for instability of the hip in a structured clinical screening programme. Of the 41 563 babies born during this period, 1639 were diagnosed as having unstable hips and 663 (1.6%) with persisting instability were splinted, five of which failed. Also, three unsplinted hips progressed to congenital dislocation, and there were four late-presenting (walking) cases, giving an overall failure rate of 0.29 per 1000 live births, with an incidence of late-walking congenital dislocation of the hip of 0.1 per 1000 live births. This study confirms that clinical screening for neonatal instability of the hip by experienced orthopaedic examiners significantly reduces the incidence of late-presenting (walking) congenital dislocation of the hip.
Of the 34 723 infants born between 1 June 1992 and 31 May 2002, the hips of 2578 with clinical instability or at-risk factors for developmental dysplasia of the hip were imaged by ultrasound. Instability of the hip was present in 77 patients, of whom only 24 (31.2%) had an associated risk factor. From the ‘at-risk’ groups, the overall risk of type-III dysplasia, instability and irreducibility was 1:15 when family history, 1:27 when breech delivery and 1:33 when foot deformity were considered as risk factors. Of those hips which were ultrasonographically stable, 88 had type-III dysplasia. A national programme of selective ultrasound screening of at-risk factors for the diagnosis of hip dislocation or instability alone cannot be recommended because of its low predictive value (1:88). However, the incidence of type-III dysplasia and hip dislocation or dislocatability in the groups with clinical instability, family history, breech position and possibly postural foot deformity as risk factors could justify a programme of selective ultrasound imaging.
