A screw, driving device, and method are provided for repairing a tissue injury of a patient, such as a meniscal tear in a knee or osteochondritis dissecans. Also disclosed are conventions useful in the prevention andor treatment of such diseases. The upper and lower platens are driven along synchronized circular paths of travel such that the mat is compressed between the platens and is propelled by the platens through the channel. The length L of the nano-fibers is greater than 0.