Osteosarcomas are the most common type of malignant osseous tumors, accounting for approximately 20% of bone cancers. Most patients affected by osteosarcoma are younger than 20 years and have lesions localized predominantly in the long bones of the extremities. Patients with osteosarcoma have pain, an enlarging mass, and restricted joint movement.

Management of osteosarcoma primarily consists of tumor resection in combination with chemotherapy. Patients with a juxta-articular osteosarcoma surrounding the knee require distal femur reconstruction, which is a challenging procedure. Preoperatively, workup should begin by obtaining radiographs of the affected extremity followed by MRI of the entire bone.

This video demonstrates radical resection of the distal femur and the proximal tibia in a 13-year-old girl. The patient had a distal femur osteosarcoma with a skip metastasis to the proximal tibia. Needle biopsy was performed before surgery. Intraoperatively, the biopsy site was excised in an elliptical manner and left in continuity with the underlying tumor. Neurovascular structures were exposed and dissected away from the tumor. Resection of the tumor was followed by prosthetic replacement reconstruction. The final step of the procedure included a formal rotational flap of the medial gastrocnemius muscle to cover the proximal tibial prosthesis.