A knee stiffness unusual etiology.

Progressive unilateral knee stiffness is an uncommon complaint in older adult. Tumor and specific infection should be considered in addition to osteoarthritis. We report a case of intracapsular and paraarticular chondroma in the infrapatellar Hoffa's fat pad that presented as a painless limited knee in 64-year old man. A physical examination revealed a firm, movable mass in the infrapatellar area. Radiographs and Magnetic resonance images showed an ovoid, well-defined, soft tissue mass with focal calcification in the infrapatellar fat pad. The mass was completely resected surgically through a medial parapatellar approach. The final pathology revealed an intracapsular and paraarticular chondroma. At follow-up, 3 years after the operation, patient was pain-free, with complete recovery of the range of motion of the knee and without any clinical or radiographic evidence of recurrence. Intracapsular and paraarticular chondroma is a rare benign lesion of the large joints (mostly the knee). The Pathogenesis of these tumours is controversial. The diagnosis is made with correlation of clinical, radiological and histological features. The treatment of choice is surgical excision.