UPmémoires

English

Introduction

Bone tumors are rare affection, particularly in children, accounting for 5 to 10% of tumors. The two main malignant bone tumors under twenty years old are osteosarcomas and Ewing's sarcomas. Biological reconstructions should be preferred in order to restore anatomical characteristics and maintain the growth mechanisms associated with function and strength. Masquelet et al. described a two-step bone reconstruction technique involving resection with temporary reconstruction by a cement spacer inducing the formation of a membrane and then reconstruction by filling this cavity with bone grafting. The aim of this study is to assess the functional and radiological outcomes in a pediatric cohort managed by the induced membrane technique for malignant bone tumors of the lower limb.

Patients and methods

Since 2000, 13 patients (6 boys and 7 girls) were included with 3 Ewing's sarcomas, 9 osteosarcomas and 1 alveolar sarcoma. 7 involved the femur and 6 the tibia. All procedures were performed by the same experienced surgeon specializing in the management of childhood bone tumors. Bone consolidation was confirmed in the presence of ossifications on the front and side X-rays views. The functional assessment of patients was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system.

Results

5 patients (38.5%) developed a nonunion following reconstruction, including one with a massive graft resorption. 3 presented a persistent nonunion at the last follow-up despite a decortication and grafting procedure. After the reconstruction step, beginning early walking at 6 weeks with partial weight bearing at 50% of body weight was a protective factor (p=0.02). The mean MSTS score was 66.6% (range from 37 to 93%). Nonunion had a pejorative impact (50% vs. 81%; p=0.03) on MSTS.

Conclusion

The management of malignant bone tumors remains a surgical challenge. Induced membrane technique is an effective technique for the reconstruction and a simple technique if it is rigorously applied. It gives good functional results seem comparable to other techniques describe in the literature. Beginning early walking at 6 weeks with partial weight bearing at 50% of body weight could be a protective factor.

Keywords : Bone reconstruction, Ewing sarcoma, Induced membrane-technique, Lower limb, Osteosarcoma, Pediatric.