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Background ACL graft-suture fixation can be constructed with needle or needleless techniques. Needleless techniques have the advantage of decreased injury, preparation time, and cost. The Nice knot is common among upper extremity procedures, and has been shown to have higher load to failure and less elongation compared with other double loop knots; however, there are no studies that have looked at its use for ACL graft-suture construct to determine whether it offers less elongation relative to other needleless techniques. Questions/purposes In a cadaver quadriceps tendon model, we asked: (1) Does the Nice knot have less elongation than the Prusik knot? (2) Does the Nice knot have increased peak load and stiffness compared with the Prusik knot? (3) What were the modes of failure of each knot? Methods Sixteen quadriceps tendon grafts were harvested from 16 cadaver knee specimens. The median (range) age of the donors was 80 years (70 to 96) and included three male and five female donors. Eight grafts were prepared with the Prusik knot and eight with the Nice knot using a braided polyblend suture. The graft-suture constructs were mounted in a materials testing machine and subjected to a tensile loading protocol beginning with pretensioning of three cycles from 0 to 100 N at 1 Hz followed by a constant load of 50 N for 1 minute then cyclic loading of 200 cycles from 50 to 200 N at 1 Hz. The constructs were loaded to failure as the final step of the loading protocol. Elongations of the construct after each loading step, peak load, stiffness, and graft cross-sectional area were compared. Results Construct elongations (median [IQR]) for the Nice knot were lower than that of the Prusik knot after pretensioning (4.4 mm [0.8] versus 5.7 mm [1.4]; p = 0.02), preloading (0.6 mm [0.3] versus 1.0 mm [0.3]; p = 0.005), and cyclic loading (7.4 mm [1.4] versus 10.9 mm [2.1]; p = 0.005). Peak load was not different for the Prusik knot construct compared with the Nice knot (334 N [43] versus 312 N [13]; p = 0.08). Stiffness of the Prusik knot construct (103 N/mm [17]) was no different than the Nice knot construct (110 N/mm [13]; p = 0.13). Graft cross-sectional area of the Prusik knot constructs (85 mm 2 [35]) were