A humeral head implant system , comprising: a head component including a first spherical articulating surface configured to articulate in a shoulder cavity, a second bottom surface extending from a rim of the first spherical articulating surface, a first cavity extending a first distance (h3) into the head component from the second bottom surface, and a second cavity extending a second distance (h2) into the head component from the first cavity along a cavity axis , the head component defining a head axis extending through a center of the first spherical articulating surface, the head axis spaced from and parallel to the cavity axis; a base component defining a slot extending from a first slot width at a third surface of the base component to a second slot width within the base component, the second slot width greater than the first slot width; and an insert component including an insert body , a first engagement feature extending from the insert body, and a slot engagement feature extending from an opposite side of the insert body as the first engagement feature, the first engagement feature configured to be received in the second cavity along the cavity axis to engage the insert component to the head component, the insert body having an insert thickness less than the first distance of the first cavity, and the slot engagement feature configured slide into the slot of the base component in a direction transverse to the cavity axis while the insert component is engaged to the head component; wherein the base component includes including an extension extending from an opposite side of the base component as the slot , characterised in that the base component further includes a plurality of legs extending radially from the extension, the plurality of legs including a first leg extending a first length from the extension , and two legs extending a second length from the extension, the second length being greater than the first length. a head component including a first spherical articulating surface configured to articulate in a shoulder cavity, a second bottom surface extending from a rim of the first spherical articulating surface, a first cavity extending a first distance (h3) into the head component from the second bottom surface, and a second cavity extending a second distance (h2) into the head component from the first cavity along a cavity axis , the head component defining a head axis extending through a center of the first spherical articulating surface, the head axis spaced from and parallel to the cavity axis; a base component defining a slot extending from a first slot width at a third surface of the base component to a second slot width within the base component, the second slot width greater than the first slot width; and an insert component including an insert body , a first engagement feature extending from the insert body, and a slot engagement feature extending from an opposite side of the insert body as the first engagement feature, the first engagement feature configured to be received in the second cavity along the cavity axis to engage the insert component to the head component, the insert body having an insert thickness less than the first distance of the first cavity, and the slot engagement feature configured slide into the slot of the base component in a direction transverse to the cavity axis while the insert component is engaged to the head component; <EOS>