Paragraph Number

78

The fastener 100 includes first and second legs 124, 126 connected to the body. The legs have a width 121, a depth 123 (FIG. 7), and a length 127 (FIG. 1A). The first and second legs may be the same size or they may be different sizes to accommodate particular anatomy. For example, the legs may have the same width and depth but have different lengths so that they can accommodate bi-cortical fixation in bone portions of varying thickness. Each leg has an elongate inboard surface 128, 130 facing the insertion axis 102 and extending from a leading end 132, 134 to a trailing end 136, 138. The elongate inboard surface 128, 130 is spaced from the insertion axis 102 a leading distance 140, 142 near the leading end and the elongate inboard surface is spaced from the insertion axis 102 a trailing distance 144, 146 near the trailing end. The leading distance 140, 142 and trailing distance 144, 146 for each leg may be equal such that the inboard surface is parallel to the insertion axis 102. The leading distance 140, 142 and trailing distance 144, 146 for each leg may be unequal such that, for example, one or both of the leg inboard surfaces may converge or diverge distally from the insertion axis 102. In one embodiment, at least one of the leading distances 140, 142 is greater than the corresponding trailing distance 144, 146 and the other leading distance 140, 142 is equal to or greater than the corresponding trailing distance 144, 146 such that the inboard surfaces 128, 130 diverge relative to one another distally or in other words in the leading direction defined by the leading ends and at least one diverges from the insertion axis 102. In the illustrative example of FIGS. 1-9, each leg diverges from the insertion axis 102 in the leading direction. The inboard surfaces 128, 130 may each diverge from the insertion axis 102 by a divergence angle. The included angle between the inboard surfaces 128, 130 is the sum of the individual divergence angles. As described above, the legs may diverge symmetrically or asymmetrically. The individual divergence angles may be in the range of 1-5 degrees. In the illustrative example of FIGS. 1-9, the divergence angles are each 3 degrees yielding an included angle of 6 degrees. When the legs are positioned in bone, the projected area of each leg perpendicular to the insertion axis affects the resistance of the leg to pulling through the bone. The larger the projected area the greater the pull through strength. For a given leg length, the area is determined by the leg depth, or for a cylindrical leg by its diameter. The body is inserted into a slot formed in the bone between the legs. As the slot width increases relative to the leg projected area, the resistance of the leg to being pulled into the slot decreases. Thus, a thinner body and consequently thinner slot increases pull through strength. This can be expressed in terms of the difference between the leg depth and body thickness or in terms of a ratio of leg depth to body thickness.

Added by DJM 12 2021