Radiofrequency Ablation in Chondroblastoma of the Femoral Head in Skeletally Immature Individuals: A Case Report

Abstract

C hondroblastoma is rare, representing only 1-2% of all primary bone tumors and 5% of benign bone tumors. 1 Most patients are under 20 years old. Chondroblastoma is usually located in the epiphysis or apophysis of long bones but it can occur in flat bones and vertebrae as well. 1 Symptoms vary from mild to severe pain for periods followed by a decrease in range of motion. The standard treatment of chondroblastoma is tumor curettage with a bone graft. 1 Management of chondroblastoma in the femoral head, however, is challenging due to the difficulty of access and the potential risk of damage to the epiphyseal plate. Radiofrequenct ablation (RFA) is a minimally invasive option for chondroblastoma management. Reports of a small series using this technique have been reported to have had excellent outcomes, but there is limited data on long term follow up. 1-5 Case ReportA 13-year old boy presented to the Orthopedic Out-patient Clinic in January 2012 with left hip pain and reported limping for 1 year. He also had night pain but no history of trauma to the left hip. His mother had brought him to a primary hospital where he was initially treated with NSAIDs but the pain did not subside. Physical examination at the Orthopedic Clinic revealed a left antalgic gait and tenderness at left groin with slightly limited internal rotation of the left hip.Plain radiographs showed an eccentric well-circumscribed osteolytic lesion at the epiphysis of the left femoral head which measured 1.5x1.5 cm (Figure 1). Preoperative CT scans of the left hip showed a welldefined homogeneous osteolytic lesion 1.3x1.7x1.4 cm with a sclerotic border at the left femoral epiphysis (Figure 2). The inferior margin of the lesion was located on the epiphyseal plate of the femoral head while the superior margin was located beneath the articular surface.Based on the pathology report, chondroblastoma of the left femoral head was diagnosed. To avoid risk of growth plate injury following open surgery, we chose percutaneous radiofrequency abrasion. AbstractSurgical management of chondroblastoma of the femoral head in skeletal immaturity is challenging due to difficult access and a risk of epiphyseal plate injury. A 13-year old boy presented with left hip pain and limping for over 1 year. Based on imaging and pathology report, chondroblastoma was diagnosed. The size of the tumor was 1.7 cm in diameter. To avoid epiphyseal plate and articular damage, percutaneous radiofrequency ablation was performed under fluoscopic guidance with a 70 o Celsius monopolar probe for 3 minutes' duration repeated 3 times. The 2 nd ablation procedure was performed after 3 months to minimize risk of recurrence. The pain had subsided at the 3 months follow up. Over the 4 years follow up period, this case shows good functional outcome without deformity of the femoral head or tumor recurrence.