Background Denosumab is a monoclonal RANKL antibody, which was originally introduced for the treatment of osteoporosis and bone metastases from solid tumors, but more recently has been used for treatment of giant cell tumor of bone (GCTB). In GCTB, denosumab has been used as a single agent in patients with inoperable tumors; it also has been used before surgery in some patients with the aim to downstage the tumor to facilitate a joint-preserving procedure (curettage) rather than a resection. However, few studies are available evaluating the benefits and risks of denosumab for the latter indication. Questions/purposes (1) Does preoperative treatment with denosumab reduce the risk of local recurrence in patients treated for GCTB? (2) Are there adverse effects of short-term denosumab use before surgery and, if so, Copyright Ó 2018 by the Association of Bone and Joint Surgeons. Unauthorized reproduction of this article is prohibited. presentation. We did not observe any adverse effects with denosumab, but we caution readers that this study was underpowered to detect even relatively common complications and relatively large differences in the risk of local recurrence. Future studies should evaluate denosumab prospectively; given the relative rarity of this tumor, we suspect multicenter studies are needed to achieve this.