Case contributed by Dr Mostafa Mahmoud El Feky


Right knee trauma and pain.

Patient Data

Age: 45
Gender: Male

CT both knees

Comminuted fracture right lateral tibial condyle reaching articular surface and extending to the proximal tibial shaft. Abundant right knee effusion with fat-fluid level (lipohaemarthrosis). Normal osseous features of the distal aspect of the right femur and proximal part of the right fibula.

Normal CT features of the left knee joint.

Case Discussion

This case represents a Schatzker I lateral tibial plateau fracture seen as a wedge-shaped pure cleavage fracture of the lateral tibial plateau with no depression. The fracture should be examined in at least two planes and in bone window setting as undisplaced fractures can be easily missed. Also, undisplaced ungapping fractures hardly appear at 3D images.

This is associated with moderate right knee effusion showing a dependent fat-fluid level. Lipohaemarthrosis occurs with fractures of long bones which involve the medullary cavity, which leads to leakage of fat from the bone marrow, with intra-articular extension of the fracture lines. Knee joint fractures are the commonest cause of lipohaemarthrosis, however, it can occur at the hip, shoulder or elbow joints. It can be easily seen in plain X-ray as well as CT due to marked density difference between fat and blood with fluid levelling, called the FBI sign.


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Case information

rID: 54900
Published: 6th Aug 2017
Last edited: 8th Aug 2017
Inclusion in quiz mode: Included

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