Arthroscopic Excision of an Intra-articular Osteoid Osteoma in the Trochlear Notch of Ulna – A Case Report

INTRODUCTION: Osteoid osteoma (OO) is a benign osteoblastic skeletal lesion commonly affecting the diaphysis of long bones. Intra-articular lesions, which present with atypical symptoms, are uncommon and elbow joint involvement is only rarely reported. Conservative treatment is ineffective and surgical excision or ablation is the therapeutic goal in symptomatic patients. Minimally invasive surgery is gaining popularity as a less morbid alternative in joints as opposed to open surgical excision. Herein, we report the first arthroscopic excision of an intra-articular OO involving the trochlear notch of ulna. CASE REPORT: A 30-year-old man presented with chronic pain and stiffness of his dominant right elbow limiting his routine activities despite treatment with analgesics. Right elbow joint showed features of moderate effusion and X-ray was normal. Computed tomography revealed an OO in the trochlear notch of ulna breaching the cortex. He underwent arthroscopic en bloc excision of the lesion followed by decompression of the surrounding sclerotic bone and radiofrequency ablation of the base. At 6th month follow-up, the patient was asymptomatic with full range of motion at elbow. CONCLUSION: Periarticular OO is a debilitating illness with atypical clinical and radiological features with no response to medical treatment. Although curative, open surgical excision often adds to the morbidity in the postoperative period. Growing experience in elbow arthroscopy has made minimally invasive surgery a safe low morbid alternative procedure. However, a precise knowledge of the instrumentation and anatomy is essential to avoid incomplete excision and recurrence with arthroscopic approach.