Abstract: A threaded insert is adapted to be secured in threaded engagement with an anchoring structure by use of locking elements carried by pockets formed in the insert along the periphery thereof contiguous with surfaces of the surrounding anchoring structure, the locking elements being formed with serrations extending out of the pockets and adapted to be forced into the anchoring structure to securely lock the insert against rotation relative thereto. A small threaded bore is also provided in each locking element which serves to facilitate removal of the locking element when a threaded element is advanced into the bore and into engagement with the pocket surface so as to force the locking element out of the pocket to allow removal of the insert. The configuration of the locking element is such that any tendency for rotation of the locking element creates increasing locking engagement with the surrounding anchoring material.