Freezing nitrogen ethanol composite in treating giant cell tumor of bone: a clinical series of 32 patients

BACKGROUND: Giant cell tumor of bone (GCTB) is a benign yet locally aggressive tumor that often affects young adults around the knee. Intralesional curettage with adjuvants reduces recurrence but complications remain. Freezing nitrogen ethanol composite (FNEC), a semi-solid cryogen, has emerged as a novel adjunct with promising early results. This study evaluated the mid- to long-term outcomes of FNEC following curettage for GCTB. METHODS: A retrospective review of consecutive GCTB patients underwent intralesional curettage and FNEC cryotherapy between 2017 and 2022. A standardized three-phase protocol (pre-cooling, freezing, thawing) was applied after intralesional curettage and before bone grafting or substitute filling, with fixation as required. Demographics, tumor characteristics, and disease status at presentation (primary vs. recurrent), oncological outcome, complications, and functional outcome were recorded. RESULTS: The cohort included 17 men and 15 women, mean age 34.8 years. Eighteen lesions (56.3%) were around the knee, the rest in the distal radius, proximal humerus, proximal femur, talus, and metatarsus. Four recurrences (12.5%) occurred, yielding 2- and 5-year recurrence-free-survival of 93.8% and 90.6%. Patients with primary lesion had superior recurrence-free survival compared with recurrent lesion (95.0% and 95.0% vs. 91.7% and 83.3% at 2 and 5 years). No recurrence was observed in primary knee lesions. Complications included one wound dehiscence and one case of subcutaneous irritation. No fractures or structural collapse was noted. The mean MSTS score was 93.2%. CONCLUSION: FNEC is a safe and effective adjuvant for curettage in GCTB, achieving excellent local control and functional outcomes with minimal complications.