Free Fibula Reconstruction for Bone Tumors Involving Humerus: Our Experience

Malignant primary bone tumors constitute only 0.2% of all malignancies in adults and approximately 5% of childhood malignancies. The humerus is a common site for malignancies like chondrosarcoma, osteosarcoma, Ewing sarcoma, and metastatic carcinomas. Management consists of multimodality treatment including chemotherapy, radiotherapy, and surgery depending on histology of the tumor and response to therapy. Reconstruction of humerus following oncological resection is a challenging procedure and the surgical options include endoprosthesis, plates, avascular bone grafts, and vascularized autologous bone using microvascular surgery.

This was a single institutional, retrospective observational study conducted at a tertiary cancer center in Northeast India from June 2018 to March 2020. All the reconstructions were done with free fibular osseous flap. Postoperative outcome was measured with Musculoskeletal Tumor Society (MSTS) scoring. Data was collected from patient records and hospital online reporting system. All data were analyzed using Statistical Package for Social Sciences, version 21. Histograms were used for descriptive statistics; Spearman's correlation was run to determine the relationship between MSTS score and age. Rest of the data was checked with Mann-Whitney and Kruskal-Wallis test. A p -value less than 0.05 was considered as statistically significant at 5% level of significance.

Six patients were included in our study ( n  = 6), three of Ewing sarcoma and one each of osteosarcoma, angiosarcoma, and chondrosarcoma. Mean age was 21.7 ± 18.6 years; there was no flap necrosis in the series. One old lady developed nonunion and fracture at the native humerus in follow-up. At the end of 1 year the mean MSTS score of the series was 24.7/30. From data analysis a significant decrease in mean MSTS score was by 0.134 times ( p  = 0.035), been observed with increasing age. The correlation between gender and MSTS score ( p  = 0.325), type of tumor and MSTS score ( p  = 0.490), and location of the tumor and MSTS score ( p  = 0.351) was statistically not significant.

Free vascularized fibular graft is an important option for bony reconstruction following tumor resection. In our small series we find it very effective for reconstruction of proximal humerus, particularly in younger patients, when microvascular expertise is present. Following a positive initial experience in humerus reconstruction with free fibular osseus flap a large study population will be considered in near future.