The effectiveness of reconstruction of the anterior cruciate ligament using the novel knot/press-fit technique: a cadaveric study

BACKGROUND: A variety of fixation devices are used for anterior cruciate ligament reconstruction with hamstring tendon grafts. These devices increase costs and can present artifacts in magnetic resonance imaging as well as complications in revision surgery. Therefore, a novel knot/press-fit technique that requires no implantable devices has been introduced. NULL HYPOTHESIS: The knot/press-fit technique restores knee kinematics as well as the more commonly used EndoButton CL fixation and has similar biomechanical properties as other devices published in the literature. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen cadaveric knees (52 +/- 7 years) were tested using a robotic/universal force-moment sensor testing system. The knee kinematics of the intact, anterior cruciate ligament-deficient, EndoButton-reconstructed, and knot/press-fit-reconstructed knee in response to both a 134-N anterior tibial load and a combined rotatory load at multiple knee flexion angles was determined. Differences between the 4 knee states were evaluated with a 2-factor repeated-measures analysis of variance (P < .05). To determine the stiffness and strength of the knot/press-fit fixation, the femur-graft-tibia complex was tested in uniaxial tension. RESULTS: In response to an anterior tibial load, the anterior tibial translation for the knot/press-fit reconstruction was found to be not significantly different from that of the intact anterior cruciate ligament as well as that of the EndoButton reconstruction (P > .05). In response to a combined rotatory load, neither reconstruction procedure could effectively reduce the coupled anterior tibial translation to that of the intact knee, and no significant difference between the 2 reconstructions could be detected (P > .05). The stiffness of the knot/press-fit complex was found to be 37.8 +/- 9.6 N/mm, and the load at failure was 540 +/- 97.7 N, which is equal to other devices published in the literature. CLINICAL RELEVANCE: The experiment suggests that the knot/press-fit technique may be a reliable alternative for the femoral fixation of hamstring tendon grafts.