An anchor assembly comprising: an externally threaded drive pin including: a shank, a head integrally connected to the shank, the head defining a mechanical engaging structure to enable rotation of the externally threaded drive pin, and an external helical thread formation integrally connected to and extending outwardly from the shank; and an externally threaded anchor including: an elongated tubular body including an inner surface defining a longitudinally extending inner channel, the body including at least two independently movable gripping arms (230a, 230b), a head integrally connected to and extending from a first end of the body and including an inner surface that defines a longitudinally extending inner channel that is aligned with the longitudinally extending inner channel of the body, the head including a mechanical engaging structure to enable rotation of the externally threaded anchor, the head also defining a drive pin head receiving recess configured to receive the head of the externally threaded drive pin, and an external helical thread formation integrally connected to and extending outwardly from part of the body, wherein the inner surface of the elongated tubular body is free of internal threads. an externally threaded drive pin including: a shank, a head integrally connected to the shank, the head defining a mechanical engaging structure to enable rotation of the externally threaded drive pin, and an external helical thread formation integrally connected to and extending outwardly from the shank; and a shank, a head integrally connected to the shank, the head defining a mechanical engaging structure to enable rotation of the externally threaded drive pin, and an external helical thread formation integrally connected to and extending outwardly from the shank; and an externally threaded anchor including: an elongated tubular body including an inner surface defining a longitudinally extending inner channel, the body including at least two independently movable gripping arms (230a, 230b), a head integrally connected to and extending from a first end of the body and including an inner surface that defines a longitudinally extending inner channel that is aligned with the longitudinally extending inner channel of the body, the head including a mechanical engaging structure to enable rotation of the externally threaded anchor, the head also defining a drive pin head receiving recess configured to receive the head of the externally threaded drive pin, and an external helical thread formation integrally connected to and extending outwardly from part of the body, wherein the inner surface of the elongated tubular body is free of internal threads. an elongated tubular body including an inner surface defining a longitudinally extending inner channel, the body including at least two independently movable gripping arms (230a, 230b), a head integrally connected to and extending from a first end of the body and including an inner surface that defines a longitudinally extending inner channel that is aligned with the longitudinally extending inner channel of the body, the head including a mechanical engaging structure to enable rotation of the externally threaded anchor, the head also defining a drive pin head receiving recess configured to receive the head of the externally threaded drive pin, and an external helical thread formation integrally connected to and extending outwardly from part of the body, wherein the inner surface of the elongated tubular body is free of internal threads.