The method of replacing a defective atrio-ventricular valve in a patient's heart with a tissue atrio-ventricular valve bioprosthesis is provided. The replacement atrio-ventricular valve from the donor heart includes an annulus, a plurality of chordae, and papillary muscles attached thereto. The surgical operation includes removal of the defective valve from the patient's heart, and the insertion of each papillary muscle of the replacement valve longitudinally into a corresponding papillary muscle in the patient's heart. The papillary muscles of the replacement valve are secured in position within the patient's heart and the annulus of the replacement valve is secured to the annulus of the patient's heart. An introducer is utilized for inserting the papillary muscles of the replacement valve into the papillary muscle of the patient's heart, using the Seldinger technique.