J Korean Orthop Assoc.  2012 Dec;47(6):468-472. 10.4055/jkoa.2012.47.6.468.

Intra-Articular Osteochondroma of the Patella

  • 1Department of Orthopedic Surgery, Daegu Fatima Hospital, Daegu, Korea. hwan1260@naver.com


Osteochondroma is one of the most common benign tumors. However, intra-articular occurrence is rare, especially in the knee joint; this is a case of osteochondroma forming bony bridge with the patella. The authors experienced a case of intra-articular osteochondroma of the left patella observed in a 58-year-old female, so we reported it with a literature review.


intra-articular osteochondroma; patella; knee

MeSH Terms



  • Figure 1 Preoperative plain radiographs of the left knee. Lateral view shows a mass-like lesion with bony shadow projecting from the inferior pole of patella.

  • Figure 2 Magnetic resonance imaging of the lesion sagittal T1, T2-weighted images show cortical and cancellous bony connection between the inhomogenous mass with marginal cartilage shadow and the posteromedial corner of the inferior pole of patella directly (arrow).

  • Figure 3 In operative field, the mass was rigidly connected with the inferior pole of patella through the bony bridge. There was no connection with infra-patellar fat pad, synovium or patellar tendon. The bony mass was excised clearly, (A) before and (B) after. The cut surface of bony bridge at the posteromedial corner (multi-arrow).

  • Figure 4 Postoperative plain radiographs show that intra-articular osteochondroma was clearly removed from the inferior pole of patella.

  • Figure 5 The excised specimen. This consists of ovoid polypoid bony tissue, measuring 3.2×2×2 cm. Cut section shows grayish thickened cartilage, of which cap thickness is 2 mm.

  • Figure 6 The microscopic finding of the excised mass (H&E, ×20). The typical findings of osteochondroma are seen.


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