Bone bruises can take months to heal

Dear Dr. Roach: Oftentimes, when I get a hard smack to a bony area, I develop a hard, tender lump on the bone. This lump will last and stay sore for weeks and sometimes months. Why does this happen? Is it normal? I’ve not heard anyone else say this happens to them. Is something wrong with my bones? I still have a sore lump on the edge of my tibia from a long time ago.

B.H.M.

Answer: We often think of bones as constant and unchanging, but bones are metabolically active, constantly reabsorbing themselves and laying down new bone to stay strong and healthy.

Of course, they need a blood supply, and one major way the bone gets blood is from the periosteum, the lining of the bone.

This has many blood vessels and nerve fibers, so a blow to the bone can cause damage to the periosteum and break blood vessels.

This is especially true for the tibia, or shin bone, which is very superficial and has a propensity to knock into things.

This causes a “bone bruise,” or subperiosteal hematoma. The plentiful nerve fibers account for the very unpleasant pain that accompanies a really hard knock on the shin. It can take weeks or months for the blood to get reabsorbed and the bone to reshape itself back into normal.

Bones consist of a shell of cancellous bone, the smooth, hard substance we all know from skeletons.

But the deeper structures of bones contain trabeculae (Latin for “small beams”), which are orderly units of bone, around which is the bone marrow, the cells that produce your blood cells.

A really hard blow can also cause a microfracture of the bone, breaking some of the trabeculae on the inside of bones. This doesn’t require the treatment of a complete fracture, but it can delay healing and cause persistent pain.

Bone bruises are common, and they don’t mean there is anything wrong with your bones.

However, this may be a chance to be sure you are getting enough calcium and vitamin D for optimal bone health.