Abstract
Purpose of study
Results clinically & statistically of a 10 year prospective observational longitudinal study of the effects of sonographic screening for ‘risk’ factors in DDH.
Methods & Results
From 1997 to 2006 the project analysed the results of a sonographic screening programme for clinical instability & ‘risk factors’ in Blackburn (modified Graf system). ‘Risk factors’ included: breech presentation, strong family history, foot deformities & oligohydramnios. Statistically 95% confidence intervals, relative risk, sensitivity, specificity PPV & NPV were calculated. The outcome measure was irreducible dislocation of the hip joint. There was a birth population of 37,510, of which 2693 were ‘at risk’ & 132 clinically unstable.
Three subsections:
| 1. Clinically unstable hips (birth) | 2 irreducible dislocations |
| 2. ‘At risk’ | 6 irreducible dislocations |
| 3. Secondary referral (GP screening) | 11 irreducible dislocations |
The overall irreducible dislocation rate was 0.51 per 1000 live births.
‘Risk factors’: mGraf Type III/IV/ Irreducible:
| CTCV: | 1: 13.8 | RR = 26.5 |
| Family history: | 1:18.5 | RR = 23.3 |
| Breech: | 1:35 | RR = 14.8 |
| Oligohydramnios | 1:99.5 | |
| TEV (postural) | 1:202 | |
| CTEV (fixed) | 0.0 |
Narrow 95% CI for Breech, CTCV & CTEV
Wide 95% CI for Family history, oligohydramnios & TEV (postural)
95% CI (RR) for Oligohydramnios & TEV not significant.
RR for clinical hip instability was 983.6
Percentage female
| 18/19 irreducible hips | 94.74% |
| 64/92 Type IV hips | 69.56% |
| 26/30 Type III hips | 86.66% |
34.15% of clinically unstable hip joints had a ‘risk factor’
Conclusion
Only 13 from 2693 ‘at risk’, had Type IV or Irreducible hips. Only 7 were treatable by splintage. Clinically & statistically screening for at ‘risk hips’ alone has a poor return. Female gender & clinical instability appear more important.
