A suture and a suture retainer are positioned relative to body tissue. Ultrasonic vibratory energy is utilized to heat the suture retainer and effect a bonding of portions of the suture retainer to each other and/or to the suture. Portions of the body tissue may be pressed into linear apposition with each other and held in place by cooperation between the suture and the suture retainer. The suture retainer may include one or more portions between which the suture extends. The suture retainer may include sections which have surface areas which are bonded together. If desired, the suture may be wrapped around one of the sections of the suture retainer. The suture retainer may be formed with a recess in which the suture is received. If desired, the suture retainer may be omitted and the sections of the suture bonded to each other.