Arthroscopic Excision of an Intraarticular Osteochondroma of Knee: A Rare Case Report

BACKGROUND: Osteochondroma is the most common benign bone tumor. Osteochondroma usually grows away from the joint and its presence in the joint is very rare and is often misdiagnosed. The presenting symptoms are generally pain, swelling, reduced range of motion and bursitis. It is rarely known to cause pressure symptoms compromising the nerves and vasculature. CASE PRESENTATION: A 27 years old male patient presented with pain and clicking sounds in the left knee two months prior to consultations with progressively worsening symptoms. There was no history of trauma, high-intensity sports, twisting of the knee or any previous surgery of the knee. A click was felt at the flexion of the knee. There was no restriction in the range of motion of the knee joint, but mild pain with over 900 to 1100 flexion of the knee. Knee Scoring of the patient measured by the International Knee Documentation Committee (IKDC), The WOMAC and The Lysholm Score was approximately 80. Plain radiography was normal. Magnetic resonance imaging (MRI) showed bony prominence at the medial aspect of the lateral condyle of the femoral bone, with impingement of the anterior cruciate ligament (ACL). Arthroscopy showed an abnormal bony growth in the intercondylar notch impinging on the ACL. The tumor was excised and histopathology findings revealed osteochondroma. DISCUSSION: A combination of clinical signs, plain radiography, and MRI can be used to make a clear diagnosis of osteochondroma. Plain radiography alone is usually insufficient in portraying the extent of clinical disease. MRI is much more useful in comparison when compared to plain radiography in the determination of an accurate diagnosis. The most accurate approach is through arthroscopy and histopathology examination. Early accurate diagnosis is important to determine the prognosis of the patient. If our case was not clearly diagnosed, the ACL would have a higher chance of rupture in this patient. CONCLUSION: Intraarticular osteochondroma of the knee can be considered a rare cause of pain and in young patients. Arthroscopy excision is accompanied with less pain, minimal infection and results in a faster recovery with Knee Scores of 100 postoperatively.