Bruised bone?

Yes the bones can be bruised! The medical term for this condition is trabecular microfracture. Before the advent of MRI, patients presenting with persistent pain after trauma without demonstrable fracture are assumed to have occult fracture. With special scan sequence on MRI (water suppressed T2WI), bone bruise can be easily depicted, as shown by the image on the left.

To qualify a lesion as trabecular microfracture, no cortical fracture must be demonstrable.

In the old times, to demonstrate this, patients have to be subjected to nuclear medicine scan which involves radiation and injection of radiopharmaceutical agent. Nowadays with MRI, the diagnosis can be obtained within minutes without any injection or radiation exposure.

Trabecular microfracture is often self limiting, with some delay in MR resolution compared to clinical improvement of symptom, which is typically within two to three months. Subchondral bone bruise (as index case) increases the risk of articular cartilage injury as the lesion is usually due to compaction of the bones. Internal knee derangement is also possible with such finding (e.g. meniscal or cruciate ligament tear) and should be excluded as well.