Pseudoarthrosis is the formation of a false joint caused by the failure of the bones to fuse. This most commonly occurs when the bones do not heal properly after a fracture.
Pseudoarthrosis usually causes pain, because the two bones are moving against each other, instead of being fused together. This movement may cause problems with metal screws or other hardware used to fuse the bones together. Additional surgery may be required to align the bones and fuse them together.
WebMD Medical Reference from Healthwise