Volume 2 | Issue 2 | May-Aug 2016 | Page 13-18 | Gurpal Singh1, Mark Edward Puhaindran1<\/p>\n
[1] Division of Musculoskeletal Oncology, University Orthopaedics, Hand and Reconstructive Microsurgery Cluster, National University Health System, Singapore.<\/p>\n
Address of Correspondence<\/strong> Introduction:<\/strong> 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. Keywords:<\/strong> Limb salvage surgery; megaprosthetic reconstruction; osteosarcoma; musculoskeletal oncology.<\/p>\n Introduction<\/strong><\/span> Three case examples of patients with osteosarcoma
\nDr. Gurpal Singh
\nDivision of Musculoskeletal Oncology, University Orthopaedics, Hand & Reconstructive Microsurgery Cluster, National University Health System, 1E Kent Ridge Road, Singapore 119228.
\nEmail: gurpal_singh@nuhs.edu.sg<\/p>\n
\nAbstract<\/span><\/h3>\n
\nIn 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.<\/p>\n
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\nMusculoskeletal 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\u20135]. 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.
\nWhen 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, intra- or 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.
\nAfter limb salvage surgery, overall survival rates of 60% to 70% at 5 years have been reported in literature [1\u20134, 9, 15]. A recent systematic review and meta-analysis by Stokke et al. evaluating the quality of life among paediatric, adolescent and young adult bone tumour survivors suggested that quality of time improves over time. According to their results, female patients and patients at older age are more likely to have a poor quality of life. Interestingly, there was no difference in outcomes between patients who underwent limb salvage surgery versus amputation for local control [16].
\nFailure rates in patients undergoing reconstruction with megaprostheses are generally higher compared to patients treated with conventional arthroplasties [7]. However, a direct comparison of study findings is difficult due to different settings and definitions used. Failure rates between 40% to 73% at 5 to 15 years have been reported from factors due to the underlying disease contributing to unfavourable early and late surgical outcome, complications can be specifically related to endoprosthetic reconstruction including aseptic loosening, periprosthetic fracture, infection, implant failure, dissociation of modular components and wear [1, 2, 5, 8, 9]. Implant survival rates for fixed-hinge prostheses have been reported to be approximately 70%, whereas rotating hinge prostheses survival between almost 80 to 100% have been reported [1, 7, 10\u201313]. A classification system proposed by Henderson et al. for megaprosthesis failure indicates 5 causes of failure, including soft tissue failure (Type 1), aseptic loosening (Type 2), structural fracture (Type 3), infection (Type 4) and local tumour recurrence (Type 5) [14].<\/p>\n
\nCase 1<\/strong> <\/span>\u2013 Osteosarcoma of the distal femur
\nA 16 year old male patient presented with right knee pain at the lateral aspect of the knee and night pain for about one month. There was no known trauma to the right knee. Clinical findings revealed tenderness over the medial and lateral aspect of the knee and a decreased range of motion 10-110\u00b0. Plain radiograph, magnetic resonance imaging, computed tomography and bone scan for local and distal staging were performed, showing an aggressive right distal femoral tumour, with extraosseous soft tissue extension abutting the quadriceps and gastrocnemius muscles, iliotibial band, and medial and lateral gutters of the knee joint (Figure 1a). No fracture or neurovascular involvement was detected. There was no evidence of distant osseous or pulmonary metastases. An open biopsy confirmed the diagnosis of a high-grade conventional osteosarcoma.<\/p>\n