Results of one-stage surgical treatment in children with Tönnis grade 4 developmental dysplasia of the hip: is it worse when it is bilateral?

This retrospective study compared the results of one-stage surgery of unilateral and bilateral Tönnis grade 4 hips (high dislocation in developmental hip dysplasia, DDH) : 41 hips, 30 patients. Mean follow-up was 56 months. Pelvic radiographs were evaluated at three time points. Acetabular inclination angle improved significantly in both groups. Results were satisfactory (Severin classes I-II) in 13 hips (68.5%) (unilateral group) and 21 hips (89.5%) (bilateral group). Functional evaluation (McKay classification) at final follow-up revealed satisfactory results in 94.8% (unilateral group) and 63.6% (bilateral group). One-stage surgery is a reliable method for treating children with unilateral or bilateral DDH.