RESECTION AND ENDOPROSTHETIC RECONSTRUCTION OF KNEE JOINT FOR OSTEOGENIC SARCOMA OF DISTAL FEMUR

Osteosarcomas are the most common solid primary bone tumours. Between 50% to 75% of osteosarcomas occur during the second decade of life [1]. Earlier most of these tumours were treated with radical amputation, radiotherapy, and chemotherapy. Now-a-days with advancement in imaging modalities, neoadjuvant chemotherapy and endoprosthetic techniques, more number of cases are being treated with wide resection of tumour and reconstruction of knee joint. This technique is useful in preserving the knee joint movement without affecting the long-term survival of the patient. The aim of this case report is to present a new method of treatment for osteogenic sarcoma of distal femur. Case Report An 18 year old male patient presented with complaints of pain and swelling around left knee joint since last 5 months. On examination, a swelling IS × 12 cm was seen on the medial aspect of left knee. Knee movements were restricted and painful. X-ray of knee joint (Fig 1) and CT scan were suggestive of osteogenic sarcoma of femur. MRI showed soft tissue extension and intramedullary extension upto 15 cms. X-ray chest and CT scan of chest did not reveal any abnormality. Incision biopsy of the tumour was done, which confirmed the diagnosis of osteogenic sarcoma. Patient received three courses of chemotherapy (Ifosfamide+Cisplatinum+ Adriamycin) followed by resection and reconstruction of the knee joint. Enblock resection of distal femur and proximal tibia was carried out followed by reconstruction of knee joint using Howmedica hinged modular resection prosthesis (Fig-2). Skin and soft tissue gap was covered with gastrocnemius flap and split thickness skin graft. Fig. 1 Preoperative X-ray photograph showing osteogenic sarcoma of distal femur Fig. 2 Postoperative X-ray photograph showing Howmedica resection prosthesis Skin dehiscence occurred over the knee joint and was covered by extracorporeal left distally based radial artery forearm flap. Knee was mobilized after wound healing and partial weight bearing with crutches started after six weeks. Postoperatively three more courses of chemotherapy were administered. At review after one year condition of the patient was stable and he was ambulant without support. Range of knee flexion was 0°–80°. X-ray and CT scan did not reveal any metastasis.