Time to full weight-bearing with the use of a calcium sulfate-calcium phosphate bone substitute as a bone void filler following extended curettage in the treatment of primary benign bone tumours.

Purpose: The primary objective of this study was to determine time to full weight-bearing after the use of a calcium-sulfate-calcium phosphate bone substitute (CaSO4/CaPO4) as a bone void filler in the treatment of primary benign bone tumours following intralesional curettage. The secondary objectives were to determine surgical complications and recurrence rates.

Methods: Retrospective review of patients identified from a surgeon-specific orthopaedic oncology database, who underwent curettage of benign bone tumours and subsequent bone void filling with CaSO4/CaPO4.

Results: A total of 39 patients (20 males, 19 females) met inclusion criteria with an average age of 31 years (range: 13 to 62 years), a median follow-up of 3.7 years, and a maximum follow-up of 11 years. The most common tumour diagnosis was giant cell tumour of bone (GCT) (n = 19), and the most common location was the proximal tibia (n = 9). The mean volume of tumour excised was 74.1 cm³ including extraosseous bone expansion due to tumour growth, with a mean of volume of 21.4 mL of CaSO4/CaPO4 used to fill the intraosseous cavitary defects to restore normal bone anatomy. None of the lesions required additional internal fixation. The primary outcome measure, average time to full weight-bearing/full range of motion, was 11 weeks and 6 weeks for upper and lower extremity lesions, respectively. Secondary outcomes included tumour recurrence requiring reoperation in five patients and infection requiring reoperation in two patients.

Conclusion: This study demonstrates that CaSO4/CaPO4 is a viable option as a bone void filler in the reconstruction of cavitary defects following removal of primary benign bone tumours. CaSO4/CaPO4 provides sufficient bone regeneration early in the post-operative period to allow progression to full weight-bearing within weeks without the need for internal fixation. There were no graft-specific complications noted.