Four-point molding: a new cast molding technique for closed reduction treatment of developmental dysplasia of the hip.

Background: In order to achieve added stability in a hip spica cast and decrease unnecessary open reduction, the authors have devised a new hip spica cast molding technique that has been named, "Four-point molding technique". Our aim was to evaluate the efficacy of this technique, in terms of its ability to deliver a stable, concentric reduction of the hip.

Material And Method: The authors retrospectively reviewed the patients, aged 6-24 months, that were diagnosed with DDH and who had undergone closed reduction with a hip spica cast. The authors used the four-point molding technique on all patients. The authors evaluated radiographs for redislocation during the 12 weeks of cast treatment and followed-up to 1 year after hip spica cast removal. 15 children (15 hips) who were treated over a 14-year period were included in the present study to determine the success rate ofthis procedure.

Results: From 1996-2010, there were 15 unilateral DDH patients who were treated with the four-point molding technique. The average age of the patients at the time of the reduction was 17 months (age range: 8-23 months). The treatment was 86.6% successful in 13 children (95% CI 0.62-0.96). The average duration in the hip spica cast was 12.5 weeks. Mean follow-up was 23.1 months. Two children were unable to be concentrically reduced with sufficient stability with closed reduction and therefore required open reduction and osteotomy.

Conclusion: Four-point molding is simple, gives good result, and with low complications. The authors propose this technique for use in closed reduction treatmentfor DDH.