Freezing tank–assisted pedicle freezing may offer a feasible approach to limb-salvage surgery in patients with malignant bone tumors of the distal femur, with limb preservation achieved in 90% of patients and no cases of nonunion observed during follow-up.
Investigators retrospectively evaluated 31 patients who underwent freezing tank–assisted pedicle freezing for distal femoral malignant bone tumors between 2018 and 2022. The patients were followed for a mean 52.3 months. Data were obtained from hospital databases, oncologic records, surgical files, and outpatient assessments. Reconstruction included bone-prosthesis composites in 14 patients, epiphyseal preservation in 10, osteoarticular reconstruction in 6, and hemi-knee reconstruction in 1. The procedure involved preserving continuity of the tumor-bearing bone while using a specialized freezing tank to apply liquid nitrogen for tumor devitalization.
The investigators assessed oncologic outcomes, complications, reoperations, and graft revision-free survival. Functional outcomes were evaluated using the Musculoskeletal Tumor Society scoring system. Additional analyses examined outcomes according to reconstruction technique and metastatic status at diagnosis.
Limb preservation was achieved in 90% of patients, whereas 10% underwent amputation following local tumor recurrence. Estimated overall survival was 93% at 2 years and 82% at 5 years. Local recurrence occurred in 10% of patients, with all recurrences confined to surrounding soft tissues and none observed within the frozen bone segments. The mean functional score was 87.7%, and no cases of nonunion were reported.
Graft revision-free survival was 82% at 2 years and 74% at 5 years. At 2 years, graft revision-free survival was 93% among patients receiving bone-prosthesis composite reconstruction, 90% among those undergoing epiphyseal preservation, and 50% among those receiving osteoarticular reconstruction. Corresponding 5-year rates were 86%, 79%, and 50%, respectively. Differences across reconstruction groups were not statistically significant.
Nononcologic complications occurred in 9 patients, including graft resorption in 6, periprosthetic graft fractures in 2, and chondrolysis in 1. Overall, 9 patients underwent reoperation, including 3 amputations for local recurrence, 4 conversions to bone-prosthesis composite reconstruction, 1 fracture fixation, and 1 resection arthroplasty for deep periprosthetic joint infection.
Graft resorption was particularly prominent among skeletally immature patients undergoing osteoarticular reconstruction. Three patients aged 5, 12, and 13 years, developed progressive epiphyseal graft resorption that became radiographically apparent between 6 and 12 months postsurgery, all of whom required conversion to bone-prosthesis composite reconstruction. Age-related differences in bone remodeling and epiphyseal vascular supply may contribute to graft resorption, making recycled osteoarticular reconstruction unsuitable for skeletally immature patients.
Oncologic outcomes also varied by metastatic status. Among 9 patients with primary bone tumors and synchronous metastatic disease at diagnosis, overall survival was 78% at 2 years and 62% at 5 years vs. 100% and 95%, respectively, among patients without metastatic disease. Complication, reoperation, local recurrence, and amputation rates did not differ statistically significantly between the groups.
The study was limited by its retrospective design, small sample size, heterogeneous tumor diagnoses, and follow-up duration that may not capture late graft failures. The absence of a comparison group prevented conclusions about the technique's effectiveness relative to conventional pedicle freezing, free-frozen autografts, or endoprosthetic reconstruction. Reconstruction methods were selected according to tumor characteristics, anatomical considerations, and surgeon preference, introducing potential selection bias. Substantial age differences across reconstruction groups and the absence of multivariable adjustment further limited interpretation of subgroup findings.
“Further comparative studies are required to better define its role relative to established reconstruction methods,” wrote lead study author Kuan-Lin Chen, of Taipei Veterans General Hospital, and colleagues.
Full disclosures of the study authors can be found in the study.
