Instruments, systems, and methods for securing anchors, elastomeric devices, and other elements in bone. In one example, an instrument includes a collar movable between a locked configuration that prevents an insertion shaft of the instrument from translating relative to a drive shaft of the instrument and an unlocked configuration that does not prevent the insertion shaft from translating relative to the drive shaft. In another example, an instrument for securing an elastomeric device to bone includes a lock movable between locked and unlocked configurations (e.g. similar to or the same as the collar in the previous example) that facilitates insertion of the elastomeric device into a bone opening when the lock is in the locked configuration, and subsequent insertion of a bone implant into the bone opening when the lock is in the unlocked configuration.