Treatment of distal femoral malignant bone tumors with freezing tank–assisted pedicle-freezing: a retrospective study of 31 patients

Biological reconstruction with recycled autografts is an established option for limb salvage after bone tumor resection, but complications such as graft failure and nonunion remain concerns. Pedicle freezing was introduced in 2010 and showed potential in reducing nonunion. However, it was technically challenging for wider adoption. A special freezing tank was developed to address the technical difficulties of the classic pedicle-freezing technique. This study aims to report the midterm outcomes of freezing tank-assisted pedicle freezing. We retrospectively reviewed 31 patients (mean age, 24.1 years; range, 5–77) with distal femoral malignant bone tumors treated with freezing tank-assisted pedicle freezing between 2018 and 2022. Reconstructions included bone-prosthesis composite (14), epiphyseal preservation (10), hemi-knee (1), and osteoarticular reconstruction (6). Mean follow-up was 52.3 months (range, 14–89 months). Oncologic outcomes, complications, reoperations, and graft revision-free survival were analyzed. Two- and five-year overall survival rates were 93.3% and 81.9%. Limb salvage was achieved in 90.3% of patients. Local recurrence occurred in 9.7%. Complications included graft resorption (6), periprosthetic graft fracture (2), and chondrolysis (1). The 2-year graft revision-free survival was 82.1%. By reconstruction type, 2- and 5-year graft revision-free survival were 92.9% and 85.7% for bone-prosthesis composite, 90.0% and 78.8% for epiphyseal preservation, and 50.0% and 50.0% for osteoarticular reconstruction; these subgroups differed markedly in age and are not directly comparable. Reoperations were required in 29.0%. No nonunion occurred. Freezing tank-assisted pedicle freezing demonstrated acceptable oncologic outcomes and a high limb salvage rate in this descriptive cohort. Graft resorption is a particular complication for skeletally immature patients receiving osteoarticular reconstruction. This single-arm series is reported as a feasibility and safety study. No comparative inference against alternative reconstruction methods is intended.