A bone anchor including an outer sleeve defining slots and an inner sleeve including fins extendable radially outward through the slots to engage surrounding cancellous bone. The outer sleeve includes an outward extending flange disposed about an opening defined by the outer sleeve configured to receive a fastener. The flange can seat against cortical bone around an opening sized for the anchor. The anchor can be a suture anchor including the fastener that engages the inner sleeve when installed therein and pushes the fins outward to engage the cancellous bone as the fastener is installed, better securing the anchor to the bone, particularly where the bone is osteoporotic, weak, broken, diseased, and/or compromised. The outer sleeve can include projections between fins to prevent rotation as the fastener is installed. A related method of using the suture anchor is provided to anchor soft tissue with a suture to bone.
