The purpose of this study is to investigate whether zoledronic acid-loaded bone cement (4mg ZOL+ gentamicin PMMA ) as adjuvant method can decrease local recurrence in patients with giant cell bone tumor following intralesional curettage surgery. The hypothesis is that patients with local administration of zoledronic acid to the bone cement has lower relapse rate compared those with traditional bone cement(gentamicin PMMA ).

The purpose of the clinical study is to investigate whether the local delivery of zoledronic acid (4mg ZOL-loaded gentamicin PMMA bone cement) as a surgical adjuvant can decrease the local recurrence rate of giant cell tumor (GCT) of bone. The investigators will also evaluate whether patients with zoledronic acid as a surgical adjuvant improves secondary outcomes, including function (MSTS and TESS), surgery related complications (henderson's failure mode) and ZOL-related complications.

Inclusion Criteria:

• patients with primary resectable GCT of bone
• lesion amenable to reconstruction (intralesional curettage) defined as having at least one intact column of bone after removal
• no previous systemic bisphosphonate or denosumab therapy
• with expected longer than 18 months of survival time
• sign the informed consent form

Exclusion Criteria:

• patients with recurrent GCT or extensive GCT which is impossible or inappropriate to use curettage surgery due to its "unresectable" nature.
• conduct unexpected surgery at other center
• the primary goal for surgery is revision
• patient conduct en-bloc/wide resection instead of curettage surgery
• patient can not conduct self-assessment during follow up
• difficulty in complete postoperative follow-up
• previous use of bisphosphonate/ZOL or denosumab drug
• patients have participated in similar research projects
• refused to sign informed consent