Percutaneous injection of calcium phosphate composite in pediatric unicameral bone cysts: a minimum 5-year follow-up study

Background: Unicameral bone cyst (UBC) is a common lesion in skeletally immature patients. Multiple treatments are proposed as curettage and autologous bone graft, percutaneous local corticoids injections, decompression with internal fixation, and injection of bioresorbable cement. Decompression, curettage, and percutaneous bioresorbable cement injection showed interesting results, but until now, no long-term follow-up was reported in pediatric patients with UBC. Methods: We retrospectively evaluated 13 pediatric patients with UBC treated with curettage, decompression, and injection of a calcium phosphate composite (CPC) at a single institution with an average F-U of 5.46 years (range 5–7 years). Functional outcomes were evaluated according to the Musculoskeletal Tumour Society (MSTS) Score. Radiographic healing was assessed with the modified Neer Outcome Rating System. Complications were recorded. Results: The mean MSTS score was 29.61 (range 28–30). No joint limitation or any pain was recorded. All patients returned to their previous level of activity. Complete healed cysts were observed in 76.9% of patients (10 of 13) and partially healed in 23.1% (3 of 13). Three fractures of the humerus occurred without any further consequence. In two cases, CPC overflow in the surrounding soft tissues was reported on post-operative X-rays, but at last follow-up, no CPC remained in the soft tissues. Conclusion: Our observations suggest that the use of curettage, decompression, and injection of CPC results in a high rate of good clinical outcomes with low recurrence rates and complications in the pediatric population with UBC at a long-term follow-up