Abstract
Method
The anteroposterior pelvic radiographs of 84 children (87 hips with developmental dysplasia) seen between 1995 and 2004 were reviewed retrospectively. Each radiograph was photographed digitally and converted to the negative using Microsoft Photo Editor. Arthrograms were also assessed at the time of femoral head reduction. The acetabular index (AI) and femoral head deformity were assessed. Acetabular response was measured using the AI at 6 and 12 months post-reduction.
Results
Mean age at presentation was 11 months for the closed reduction group, versus 19 months for those with an arthrographic soft tissue obstruction requiring open reduction. Additionally, the average age of the children that underwent open reduction who later required a Salter osteotomy was 27 ± 3 months compared to an average of 14 ± 1.5 months for those who did not.
The acetabular response was maximal during the first 6 months following treatment. Closed reduction (24 hips) gave comparable results to open reduction (63 hips), although the initial AI was greater in those requiring open reduction (39.5 ± 6.3° versus 36.1 ± 4.6°). Using two separate Bonferroni pairwise comparisons revealed no statistical difference in response between closed and open reduction. Arthrography revealed that hips requiring open reduction were more deformed, with spherical femoral heads in 29% as opposed to 68% in the closed reduction group. The AI was also slightly less (36.6 ± 3.2°) when the femoral head was spherical in comparison to those hips with an aspherical femoral head (38.0 ± 6.6°).
Conclusion
Age at presentation and femoral head deformity therefore influence the outcome of reduction, but the acetabular index improves to a similar degree whether closed or open reduction is required.
