The management of developmental dysplasia of the hip (DDH) requiring open reduction between 12 and 18 months of age is controversial. We compare the outcome of medial approach open reduction (MAOR) versus delayed anterior open reduction with Salter osteotomy in such patients.

17 consecutive patients who underwent MAOR aged 12–20 months were reviewed (mean follow-up of 40 months, range 6–74). This group was compared to 15 controls who underwent anterior reduction and Salter osteotomy aged 18–23 months (mean follow-up of 44 months, range 14–134).

13 of the 17 (76%) MAOR patients required subsequent Salter osteotomy at a mean of 22 months post-reduction, with a further 2 patients under follow-up being likely to require one. Acetabular index improved from 42 (32–50, SD − 5.5) to 16 (7–24, SD − 4.5) in the MOAR group after Salter osteotomy compared to an improvement of 40 (30–53, SD − 6) to 13 (4–24, SD − 5) in the control group (p>0.05). Acetabular index at last follow-up was within normal limits in 15 of 17 (88%) MAOR patients. All patients in the control group had acetabular indices (or centre-edge angles of Wiberg) within the normal range.

There was 1 subluxation (7%) in the control group. There were 6 cases (33%) of post-operative avascular necrosis (5 Kalamchi & MacEwen Grade I, 1 Grade 2) in the MAOR group and 6 (40%) in the control group (5 Grade 1, 1 Grade 4).

All of the MAOR patients had good or excellent clinical results according to McKay's criteria, compared to 14 out of 15 (93%) controls.

This study suggests that MAOR or delayed open reduction and Salter osteotomy is a reasonable treatment for children with DDH presenting between the ages of 12 and 18 months. However, the majority of MAORs are likely to require a subsequent Salter osteotomy.