The ornamental design for a knotless anchor, as shown and described.
FIG. 1 is a perspective view of a knotless anchor showing our new design;
FIG. 2 is a front elevational view of the knotless anchor of FIG. 1;
FIG. 3 is a rear elevational view of the knotless anchor of FIG. 1;
FIG. 4 is a left-side elevational view of the knotless anchor of FIG. 1;
FIG. 5 is a right-side elevational view of the knotless anchor of FIG. 1;
FIG. 6 is a top plan view of the knotless anchor of FIG. 1; and,
FIG. 7 is a bottom plan view of the knotless anchor of FIG. 1.
The broken lines shown in the drawings are included for the purposes of illustrating portions of the knotless anchor and form no part of the claimed design.