|Year : 2013 | Volume
| Issue : 2 | Page : 155-158
A rare case of osteosarcoma of the proximal fibula; challenges of surgical management
Atmananda s Hegde, Ravindra M Shenoy, Deepak K Rai
Department of Orthopedics, Yenepoya Medical College, Mangalore, Karnataka, India
|Date of Web Publication||13-Dec-2013|
Atmananda s Hegde
Department of Orthopedics, Yenepoya Medical College, Mangalore - 575 002, Karnataka
Source of Support: None, Conflict of Interest: None
Osteosarcoma is the most common primary malignancy of bone if we exclude the marrow-based malignancies such as myeloma, lymphoma, and leukemia. Osteosarcoma is the eighth most common form of childhood cancer, comprising 2.4% of all malignancies in pediatric patients, and approximately 20% of all primary bone cancers. The proximal fibula is a very rare site for osteosarcoma, and in Mayo series, reported incidence was only 2%. The purpose of this article is to report a very rare presentation of osteosarcoma in proximal fibula and to discuss the challenges in its surgical management. Proximal fibula osteosarcoma carries a good prognosis if sound oncological margins are achieved during the initial surgery. In addition, lateral soft tissue structures should be meticulously reconstructed to prevent post-operative knee instability and to ensure a good functional outcome.
Keywords: Osteosarcoma, proximal fibula, wide resection
|How to cite this article:|
Hegde As, Shenoy RM, Rai DK. A rare case of osteosarcoma of the proximal fibula; challenges of surgical management. Arch Med Health Sci 2013;1:155-8
| Introduction|| |
Osteosarcoma is an aggressive malignant neoplasm arising from primitive transformed cells of mesenchymal origin (and thus a sarcoma) that exhibit osteoblastic differentiation and produce malignant osteoid. Osteosarcoma is the eighth most common form of childhood cancer, comprising 2.4% of all malignancies in pediatric patients, and approximately 20% of all primary bone cancers.  It originates more frequently in the metaphyseal region of tubular long bones, with 42% occurring in the femur, 19% in the tibia, and 10% in the humerus. About 8% of all cases occur in the skull and jaw, and another 8% in the pelvis.  The proximal fibula is a very rare site for osteosarcoma, and in Mayo series, reported incidence was only 2%.  Treatment typically includes pre-operative chemotherapy, surgical resection, and post-operative chemotherapy. Limb-salvage procedures with wide surgical margins are the mainstay of surgical intervention. The management of osteosarcoma of the proximal fibula is demanding for the treating surgeon because of the proximity of the common peroneal nerve to the lesion. Resection of malignant tumors often requires wide surgical margins and to obtain such margin, at times resection of the common peroneal nerve is done, which leads to post-operative foot drop. Also, resection of the lateral collateral ligament and biceps femoris tendon can cause significant lateral instability. The purpose of this article is to report a rare presentation of osteosarcoma in proximal fibula and discuss the difficult aspects of its management.
| Case Report|| |
A 14-year-old boy presented with pain in the lateral aspect of right knee and upper part of leg since three months. There was no history of preceding trauma. Pain was increasing in severity, but he was able to walk without using any walking aids. There was no history of fever, loss of appetite or loss of weight, and there was no history of swelling anywhere else in the body. Examination revealed an ill-defined swelling over the proximal third of fibula, which was tender with local rise of temperature, and it was firm to hard in consistency with smooth surface and appeared to be continuous with the fibula distally. Movements of the knee joint were full range but painful in terminal flexion. There was no evidence of distal neuro-vascular deficits. Plain radiographs revealed an expansile lytic lesion involving the proximal third of fibula with some patchy sclerosis and cortical breach. Proximal fibular epiphysis seemed to be free of lesion [Figure 1]. Chest x-ray was normal, and serology revealed no abnormality. MRI also showed an aggressive lesion with cortical breach and soft tissue extension involving proximal third of right fibula with sparing of proximal epiphysis. Chest CT scan revealed no evidence of metastasis. A clinico-radiological diagnosis of malignant neoplastic lesion of proximal fibula was made, and lesion was subjected to core needle biopsy. Biopsy revealed histopathological features of osteosarcoma. So, a wide excision of the lesion with safe margin was planned. During the surgery, thigh tourniquet was used without exsanguination. A longitudinal incision overlying the proximal fibula was used to allow excision of biopsy site. By sharp dissection, expanded proximal end of fibula was isolated sacrificing superficial peroneal nerve, anterior tibial artery and the attachment of lateral collateral ligament and biceps femoris. Care was taken to leave healthy soft tissue sleeve all around the expanded proximal fibula and tumor removed after osteotomizing the fibula 2 cms distal to medullary level of tumor spread as indicated by MRI. Common peroneal nerve was preserved as it was tumor-free and could be mobilized without tumor spillage. Cut ends of lateral collateral ligament and biceps femoris tendon was anchored to proximal tibia and surrounding capsule for lateral stability [Figure 2]. Limb was immobilized in an above knee slab. Histo-pathological examination of the excised specimen was suggestive of osteoblastic osteosarcoma with tumor-free margins all around. Post-operative period was uneventful [Figure 3]. Three weeks after surgery, multidrug adjuvant chemotherapy was started and continued for six cycles at three weekly intervals. Patient was mobilized non-weight bearing with a hinged knee brace two weeks after surgery, and full weight bearing with the brace was started after six weeks. Brace was discontinued after 12 weeks. At the latest follow-up (six months), patient had full range of knee motion, grade 1 varus instability, no foot drop, and no radiological evidence of tumor recurrence [Figure 4].
|Figure 2: Intra-operative pictures showing isolated common peroneal nerve and the excised proximal fibula|
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| Discussion|| |
Osteosarcoma is the most common primary malignancy of bone if we exclude the marrow-based malignancies such as myeloma, lymphoma, and leukemia. The site of predilection is the metaphyseal area of long bones, with 42% occurring in the femur, 19% in the tibia, and 10% in the humerus. About 8% of all cases occur in the skull and jaw, and another 8% in the pelvis. 
The proximal fibula is a rare site representing about 2% of all osteosarcomas.  Even though osteosarcomas have been historically treated by amputations, the emphasis in recent times is towards limb salvage combined with chemotherapy to prevent micro and macro metastasis. On the other hand, an above knee amputation is preferable to limb salvage when confronted with the following situations: Gross invasion of the tibia, extensive multi-compartment involvement especially of the posterior deep compartment, multi-compartment contamination from a previous biopsy or attempted resection, anomalous vascular patterns, especially absent posterior tibial artery, and intra-articular extension of the tumor. Long-term survival probabilities for osteosarcoma have improved dramatically during the late 20 th century and approximated 68% in 2009.  The surgical treatment of osteosarcoma of proximal fibula is challenging as the common peroneal nerve and anterior tibial artery need to be sacrificed in order to achieve wide and tumor-free margins of resection, thereby resulting in an iatrogenic foot drop. The resultant loss of function necessitates the post-operative use of a functional ankle foot orthosis. In addition, stability of the knee joint is also at stake as the insertions of the lateral collateral ligament and biceps femoris from the fibular head are also resected.  Biopsy is mandatory before definitive surgical intervention. Core needle biopsy is preferable because of relatively less local contamination and high chance of histological diagnosis.  The surgical biopsy should be carefully planned according to tumor biopsy principles. We always approach the proximal fibula through the lateral compartment. En bloc resection is planned only after careful assessment of biopsy findings.  There are reports in the literature, which study the intentional marginal resection of the osteosarcoma of the proximal fibula in order to preserve the limb function. ,, In our patient, we intentionally preserved the common peroneal nerve as it was tumor-free and could be safely mobilized without tumor spillage. The anterior tibial artery is ligated routinely to secure a safe margin; this poses no problems to lower limb viability as long as the posterior tibial artery is preserved. The peroneal artery may also be sacrificed, if needed to achieve adequate surgical margins.
The LCL is the main resistor to varus loading in a partially flexed knee.  The biceps femoris imparts a posteriorly directed force to the proximal tibia and the iliotibial band giving anterior stability, reducing the strain on the anterior cruciate ligament.  The iliotibial band helps to control both the anterior and medio-lateral motions of the knee.  En bloc resection of the proximal fibula detaches the attachments of these structures, contributing to lateral instability of the knee joint.  These lateral supporting structures thus need to be meticulously repaired to prevent post-operative knee instability.
Although some authors have reported good function after resection without ligament reconstruction,  re-attaching the LCL is a simple technique, associated with minimal morbidity and good functional outcome. Post-operative chemotherapy plays an important role in the management of osteosarcoma to prevent micro-metastasis and local tumor recurrence. Post-operative adjuvant chemotherapy definitely improves disease-free and overall survival in patients with osteosarcoma. 
Proximal fibula osteosarcoma carries a good prognosis if sound oncological margins are achieved during the initial surgery. In addition, lateral soft tissue structures should be meticulously reconstructed to prevent post-operative knee instability and to ensure a good functional outcome.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]