Injectable calcium sulfate vs mixed bone graft of autologous iliac bone and allogeneic bone: Which is the better bone graft material for unicameral bone cyst in humerus?

Unicameral bone cyst (UBC) is a benign fluid-filled lesion, mainly located in the metaphyses of long bones in children and adolescents. Elastic stable intramedullary nail (ESIN) is adopted in our institute for UBCs since 2010, and bone grafting was performed simultaneously. This study aims to evaluate the efficacy of ESIN decompression combined with different bone graft materials.All patients with the diagnoses of UBCs of the humerus, treated with ESINs and bone grafting between January 2010 and June 2018, were analyzed retrospectively. The bone grafting included injectable calcium sulfate, a mixture of the autologous iliac bone and allogeneic bone. All patients were categorized into 2 groups: ICS (injectable calcium sulfate) group and MIX (a mixture of the autologous iliac bone and allogeneic bone, ratio: 1:3) group. All the information was collected from the Hospital Database.In all, 17 patients (8.8 ± 2.3-year-old, male 8, female 9) in the ICS group and 19 patients (8.9 ± 1.9-year-old, male 10, female 9) in the MIX group were included in this study. Patients in both groups were followed up for more than 2 years (average, 3.4 ± 1.3 years). No recurrence was observed in either group. There was no significant difference between the two groups concerning the patient's demographic parameters, including sex, age, and affected side. All patients in both groups displayed excellent and good shoulder function, and there was no significant difference between the 2 groups (P = .29). As for the Capanna classification, there was no significant difference between these 2 groups (P = .78).Intramedullary nailing has the advantage of a minimally invasive procedure, immediate stability, and continuous decompression. ICS showed similar results as a mixture of the autologous iliac bone and allogeneic bone.