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

Abstract

© 2014, Medical Association of Thailand. All Rights Reserved. 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 a14-year period were included in the present study to determine the success rate of this 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 followup 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 treatment for DDH.