What type of fracture is classified as intra-articular, presenting with effusion?

The classification of a fracture as intra-articular is significant as it indicates that the fracture line extends into the joint space, which can lead to complications such as joint effusion. Among the options provided, the patellar sleeve fracture is characterized by its location and the associated clinical presentation.

A patellar sleeve fracture typically occurs in the context of a fall or a direct blow to the knee and involves the cartilaginous portion of the patella. Due to its intra-articular nature, it can lead to joint effusion, which is an accumulation of fluid in the joint cavity. This fluid buildup happens due to the inflammatory response initiated by the injury and can often be noted during a physical examination.

In contrast, while other fractures listed may have important clinical implications and might involve joint structures, they do not specifically characterize intra-articular fractures leading to effusion to the same extent. For example, the tibial tubercle fracture primarily affects the patellar tendon attachment and may not involve the joint space directly. Femoral neck fractures involve the hip joint but often do not present with effusion in the same classic manner as seen in knee joint injuries. Radial head fractures are significant in the context of elbow injuries but are less commonly associated with effusion compared