Bumps or prominences on joints are common after injury to the joint, tendon, or ligament to the joint. The body will overcompensate for loss of bone or soft tissue by producing extra bone or tissue.

In the case of a finger fracture a process called bone remodeling takes place. First new bone cells develop at the fracture site. Then a bone bridge across the two broken pieces occurs. Then the body goes back and "remodels" the lump of bone at the site. It removes some (not all) of the extra bone it formed in the first place.

On the outside this can look like a bump. The same kind of appearance can occur when a ligament or tendon is torn and isn't repaired. The end of the torn tissue pulls back into a ball that looks like a bump on the outside.

Arthritis is possible after joint injuries of this kind. A baseline X-ray may be a good idea to show the condition of the joint now. Future X-rays can show any changes that occur. This kind of information can help guide treatment now and later.