Source : Webster's Revised Unabridged Dictionary (1913)

Impacted \Im*pact"ed\, a.
   Driven together or close.

   {Impacted fracture} (Surg.), a fracture in which the
      fragments are driven into each other so as to be
      immovable.

Source : WordNet®

impacted fracture
     n : fracture in which one broken end is wedged into the other
         broken end