Limb salvage with megaprosthesis in extremity osteosarcoma –a case-based approach

Introduction Musculoskeletal oncology is a rapidly evolving field in orthopaedic surgery and surgical management for patients with osteosarcoma has progressed significantly over the past three decades. Due to advances in neoadjuvant treatment, imaging modalities, surgical techniques and material and prosthesis designs, amputation is no longer considered as standard of care in most cases. Literature is currently reporting limb salvage surgeries in 85% to 95% without compromising oncological principles when compared to amputation [1–5]. Main objectives of limb salvage surgery include maximized functional outcome, satisfactory wound coverage for adjuvant therapy and optimized aesthetic outcome without compromising oncologic principles [6]. The reconstructive options for limb salvage surgery can be thought of as biological (autograft, allograft etc.) or endoprosthetic. Sometimes, a combination of both may be necessary. When considering treatment options for patients with osteosarcoma, several factors need to be considered, including the response to neoadjuvant chemotherapy, evidence of periprosthetic fracture, anatomic site, involvement of soft tissue, joint and neurovascular structures as well as the evidence of metastases at diagnosis. Adequate margin control during surgery is crucial. Surgery represents only one component of the multidisciplinary treatment protocol of osteosarcoma patients. Since the 1970s, the role of neoadjuvant therapy has evolved and intense multi-agent chemotherapy has improved the prognosis significantly by eradicating accompanying micrometastases and also reducing the reactive zone around the tumour. The main drawback of chemotherapy prior to surgery includes immunosuppression. Therefore, a multidisciplinary approach between medical oncologists and the surgical team is essential in order to optimise treatment for the patient. After completion of neoadjuvant chemotherapy, re-staging is performed to assess response to chemotherapy and verify resectability and evaluate margins prior to proceeding with definite surgery. Limb salvage surgery for osteosarcoma is typically described as consisting of three parts, starting with en bloc resection of the tumour. Based on the exact location, intraor extra-articular resection may be considered. In skeletally immature patients, the possibility of physis preservation should be considered. Thereafter, the bone defect is reconstructed. The third part of the surgery consists of soft tissue coverage and functional re-establishment. Treatment protocols for osteosarcoma further include the administration of adjuvant chemotherapy and subsequent long-term surveillance. After limb salvage surgery, overall survival rates of 60% to 70% at 5 years have been Introduction: Musculoskeletal oncology is an evolving field in orthopaedic surgery and surgical management for patients with osteosarcoma has changed fundamentally over the past three decades. Osteosarcoma is a rare tumour, but it is the most common type of primary bone cancer with a biomodal peak. Primary cases tend to occur within the first two decades of life and secondary osteosarcomas affect older patients. Common causes of secondary osteosarcoma include Paget's disease of bone and radiation exposure. Due to advances in chemotherapeutic regimes, imaging modalities, surgical techniques, material and prosthesis designs, amputation is no longer considered as treatment of choice for most patients. Limb salvage surgery including endoprosthetic reconstructions is also constantly evolving, addressing surgical challenges such as margin control, reconstructive procedures and soft tissue management. In this review, we focus our discussion on the management of patients with osteosarcoma undergoing megaprosthetic reconstruction. Based on three real cases (osteosarcoma of the distal femur, pelvic osteosarcoma involving the hip joint and osteosarcoma of the proximal tibia), this paper aims to highlight surgical challenges that sometimes need to be overcome in this very challenging field.