Answer:
SPONTANEOUS OSTEONECROSIS OF KNEE (SONK
Findings:
Subchondral TI/STIR hypointense fracture line with STIR hyperntensities reflecting marrow edema seen in the medial femoral condyle. Soft tissue edema seen abutting the medial collateral ligament , reflecting sprain.
Discussion:
SONK is Necrosis of weight bearing portion of tibia or femur with associated subchondral fracture or collapse. Invariably Unilateral The medial side of the joint is the side that is most commonly involved, and the lesion occurs commonly in the femoral condyle than in the tibial plateau. Intense pain after trivial trauma in elderly patients. Diffuse increased signal within subchondral bone of femoral condyles or tibia. Associated Meniscal tear .
DD – Secondary Osteonecrosis- Relatively Younger Age group Lesions are larger Bilateral Involvement (30-80%) Demarcation rim seperating necrotic bone and marrow from adjacent viable tissue -Pathognomonic Subchondral fracture in young active patients. Osteochondritis Dessicans -lateral aspect of medial femoral condyle.
REFERENCES: Osteonecrosis of the knee: differences among idiopathic and secondary types. J.A NARVAEZ et al Rheumatology (2000) 39 (9): 982-989.
Contributed By: Dr.Babu Peter, Associate Professor, B.I.R, Chennai, India
SPONTANEOUS OSTEONECROSIS OF KNEE (SONK
Findings:
Subchondral TI/STIR hypointense fracture line with STIR hyperntensities reflecting marrow edema seen in the medial femoral condyle. Soft tissue edema seen abutting the medial collateral ligament , reflecting sprain.
Discussion:
SONK is Necrosis of weight bearing portion of tibia or femur with associated subchondral fracture or collapse. Invariably Unilateral The medial side of the joint is the side that is most commonly involved, and the lesion occurs commonly in the femoral condyle than in the tibial plateau. Intense pain after trivial trauma in elderly patients. Diffuse increased signal within subchondral bone of femoral condyles or tibia. Associated Meniscal tear .
DD – Secondary Osteonecrosis- Relatively Younger Age group Lesions are larger Bilateral Involvement (30-80%) Demarcation rim seperating necrotic bone and marrow from adjacent viable tissue -Pathognomonic Subchondral fracture in young active patients. Osteochondritis Dessicans -lateral aspect of medial femoral condyle.
REFERENCES: Osteonecrosis of the knee: differences among idiopathic and secondary types. J.A NARVAEZ et al Rheumatology (2000) 39 (9): 982-989.
Contributed By: Dr.Babu Peter, Associate Professor, B.I.R, Chennai, India