Calcium sulphate pellets (Osteoset®) improve bone graft incorporation, but not femoral head sphericity after shelf acetabuloplasty for Perthes’ disease

Abstract

Introduction: Outcome of shelf acetabuloplasty in management of late onset Perthes’ disease can be affected by shelf resorption and inadequate femoral head containment. Various agents have been tried to enhance bone graft incorporation and reduce its resorption. The aim of this study was to assess whether Osteoset® (calcium sulphate pellets) can stimulate autogenous bone graft incorporation and prevent bone resorption after shelf acetabuloplasty for Perthes’ disease and whether its use can improve femoral head remodelling. Methods: Thirty-two children with Perthes’ disease who underwent shelf acetabuloplasty were divided into two groups. In 15 patients (study group) Osteoset (10 ml) mixed with autogenous bone grafts to create extra ‘shelf’ over deficient acetabulum was used. Seventeen patients who served as a control group were managed by shelf acetabuloplasty using autogenous bone graft without Osteoset. Both groups were similar with regards to age and severity of the condition. The mean age at operation was 9 years and 4 months. The mean follow-up was 53.3 and 61.5 months for Osteoset and control groups, respectively, when all patients reached skeletal maturity. On serial radiographs shelf area, extra-osseous shelf length, acetabular coverage and graft incorporation and femoral head sphericity were assessed. Results: Immediately post-operatively the shelf area and shelf length were similar in both groups. From 6 weeks post-operatively and thereafter shelf area and shelf length were significantly better in patients from the study (Osteoset) group. Patients from the control group showed a steady decline in graft area throughout the follow-up period. Graft incorporation was also faster in the Osteoset group. However, femoral head sphericity assessed by Stulberg classification was similar in both groups. Conclusion: Osteoset pellets improve graft volume, encourage earlier graft incorporation and inhibit later shelf resorption. Adding Osteoset does not improve femoral head remodelling following shelf acetabuloplasty for Perthes’ disease.