A prosthetic acetabular cup inserter and impactor has a body, and a cup engaging element disposed at a first end of the body and adapted to engage an inner surface of a cup with which it is used via outward biasing of the cup engaging element. The cup engaging element increases in cross-sectional area from an inner end thereof to a fullest transverse section, and decreases in cross-sectional area from said fullest transverse section to an outer end thereof. The cup engaging element has a tapered central bore engaged by a conically tapered actuation element moveable in the bore. The cup engaging element has a slot therethrough allowing the element to resiliently expand on movement of the actuator in the bore.
