A 15 year prospective, observational cohort study was undertaken to assess selective screening of DDH in males and females referred with risk factors only.

Individuals born breech or with evidence of a strong family history for DDH were the ‘risk factors’ studied. All were clinically examined and sonographically screened by one Consultant Paediatric Orthopaedic surgeon. Irreducible hip dislocation rate was the primary outcome measure.

From a cohort of 64670 live births, 2,984 neonates/infants, 46.1 per 1000 live births [95% CI 44.6 to 47.8 per 1000 live births] were referred and sonographically screened with ‘pure’ risk factors of breech presentation and/or family history, with clinical stability. 1360 were male, of which 4 were identified as having ‘pathological’ DDH; an incidence of 1 in 333 of those males referred [95 CI 0.001, 0.008]. 1624 were female, of which 45 were identified as having ‘pathological’ DDH; an incidence of 1 in 36 of those females referred [95% CI 0.021, 0.037]. There was a significant difference in the number of female individuals sonographically diagnosed as having ‘pathological’ DDH compared to males (p<0.001). Four individuals were diagnosed with irreducible hip dislocation, 0.06 per 1000 live births [95% CI 0.24, 0.159 per 1000 live births]. All were in females. Additionally, there were 2 female individuals; both with family history of DDH (1^st cousin splinted and sister splinted, respectively) as a risk factor, referred late.

Our study suggests that there is a significant difference between the incidence of female and male individuals diagnosed with ‘pathological’ DDH, in those referred purely with risk factors (breech and family history). These findings question the current screening policy for ultrasound examination of males with risk factors in the absence of clinical instability, and may influence future DDH screening programme policy.

Level of evidence: II

The purpose of the study was to identify risk factors that are associated with re-displacement of the hip after surgical reconstruction in cerebral palsy.

Retrospective review of children with cerebral palsy who had hip reconstruction with proximal femoral varus derotation osteotomy (VDRO) and Dega-type pelvic osteotomy, between 2005–2012, at a UK and European institution, was performed. Patient demographics, GMFCS, clinical and radiological outcome were assessed as well as the presence of pelvic obliquity and significant scoliosis (Cobb angle > 10 degrees). Redisplacement was defined as Reimer's Migration Index (MI) >30% at final follow-up. Logistic regression analysis was used to assess which factors were predictive of redisplacement and adjusted for clustered variables (α = 0.05).

Eighty hips were identified in 61 patients. The mean age at surgery was 8.8 years (± 3.3). Mean MI pre-op was 68% (± 23%) and post-op was 8% (± 12%). At a mean follow-up, of 3.2 years (± 2.0), 23 hips had a MI >30%. Of these; five were symptomatic, and one had required a salvage procedure. Metalwork removal was undertaken in 14 hips. Logistic regression demonstrated that the pre-operative MI and the percentage of acute correction were significant predictors of re-displacement. If the pre-operative MI was greater than 65 percent, the odds ratio (OR) for redisplacement was 5.99 (p = 0.04). If correction of the MI was less than 90% of the pre-operative MI, the OR for re-displacement was 4.6 (p = 0.03). Age at the time of surgery, GMFCS, pelvic obliquity and scoliosis were not predictive of re-displacement.

These results, firstly, highlight the importance of hip surveillance in children with cerebral palsy to allow timely intervention to ensure adequate radiological outcomes. Secondly, as in developmental hip dysplasia, full concentric reduction is essential to reduce the risk of re-displacement, with its associated clinical consequences.

Aims

We aimed to examine the true incidence of DDH in our area, and to investigate both known and unknown risk factors for the condition.

Introduction:

Risk factors for developmental dysplasia of the hip (DDH) in early infancy have never been validated from basic principles; their relevance remains controversial.