CASE 123

By: Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: 14-year-old boy complaining of anterior knee pain with a lump seen anteriorly.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

The lateral view of the left knee [A] demonstrates soft tissue swelling of the patellar tendon. Fragmentation of the apophysis of the tibial tubercle is also seen.

Ultrasound examination in the sagittal orientation [B and C] show swelling of the unossified cartilage and overlying tissue. Furthermore, there is fragmentation and irregularity of the ossification center. Thickening of the distal patellar tendon is seen with an infrapatellar bursitis is noted.

DIFFERENTIAL DIAGNOSIS:

·        Osgood-Schlatter disease.

·        Sinding-Larsen-Johansson syndrome is equivalent to involve the inferior patella.

·        Jumpers knee which involve the patellar tendon without involvement of the bone.

·        Infrapatellar bursitis.

DIAGNOSIS:

Osgood Schlatter disease of the left knee.

PEARLS AND DISCUSSION:

Osgood-shlatter disease or tibial osteochondritis is a traction apophysitis of the patellar tendon near its insertion within the tibial tuberosity. Osgood-Shlatter disease is a clinical diagnosis and is the most common cause of anterior knee pain in adolescents. The MRI diagnostic hallmark is distal patellar tendinosis with increased fluid signal around and deep infra-patellar bursitis as well as osseous edema of the tibial tuberosity.

The disease appears in active adolescents who jump and kick. And it can happen bilaterally in 25-50% of the patient’s. Adult cases have been reported.

On x-rays, it is important not to equate fragmentation of the apophysis with Osgood Schlatter disease as may be seen with secondary centers of ossification.

Ultrasound can detect swelling within the soft tissue as well as in the cartilage. The primary role for ultrasound is to detect the disease in its early stage.

MRI as expected is more sensitive and specific and will demonstrate anterior swelling around the tibial tuberosity with loss of the infrapatellar Hoffa’s fat pad, thickening and edema of the Patellar tendon. Infrapatellar bursitis will be seen, and bone marrow edema could be detected in the tibial tubercle.

Treatment is usually with [RICE] that is rest, ice, decreasing activities and elevation. Nonsteroidal anti-inflammatory drugs can be given. Rare cases surgery can be done to excise the ossicle.

FURTHER READING:

1.      Stevens MA, El-khoury GY, Kathol MH et-al. Imaging features of avulsion injuries. Radiographics. 19 (3): 655-72. 7.

2.      Rosenberg ZS, Kawelblum M, Cheung YY et-al. Osgood-Schlatter lesion: fracture or tendinitis? Scintigraphic, CT, and MR imaging features. Radiology. 1992;185 (3): 853-8. 

3.      Hunter TB, Peltier LF, Lund PJ. Radiologic history exhibit. Musculoskeletal eponyms: who are those guys? Radiographics. 20 (3): 819-36.