What structure is most likely to require protection through immobilization after an elbow injury involving a fat-pad sign?

• A. The radial head
• B. The trochlea
• C. The lunate
• D. The coronoid process

Answer: (B)

The fat-pad sign on imaging, particularly seen on lateral X-rays of the elbow, suggests the presence of an underlying injury, typically related to a fracture or joint effusion. When it comes to elbow injuries, the structure most likely to require protection through immobilization following a significant fat-pad sign is the trochlea.

The trochlea, which is part of the humerus, plays a crucial role in the elbow joint as it articulates with the ulna. Injuries to this structure can lead to instability and compromised function of the elbow, necessitating immobilization to promote healing and prevent further damage.

In contrast, while the radial head, coronoid process, and lunate can also be involved in elbow injuries, the trochlea is particularly emphasized in this context due to its integral role in hinge joint functionality and stability. Thus, in cases where there is a fat-pad sign indicative of potential intra-articular fracture, the trochlea should be suitably protected to ensure appropriate recovery and functionality of the elbow joint.