BACKGROUND: Fixation of an anterior cruciate ligament graft at the joint line with an interference screw restores anterior laxity better than low-stiffness distal fixation with double staples and sutures tied to a post at implantation in porcine bone. HYPOTHESIS: Fixation of an anterior cruciate ligament graft with a high-stiffness distal fixation device restores anterior laxity and knee stiffness as well as joint line fixation with an interference screw in human bone. STUDY DESIGN: Controlled laboratory study. METHODS: Eleven cadaveric knees with foam reinforcement of the bone were reconstructed with a double-looped tendon graft and fixed with an interference screw and 3 high-stiffness methods of fixation (tandem washer, WasherLoc, and WasherLoc with bone dowel). Anterior laxity at 225 and 110 N of anterior load and knee stiffness were measured at 0 degrees , 30 degrees , 60 degrees , 90 degrees , and 120 degrees of flexion with a 6 degrees of freedom load application system. RESULTS: The increase in anterior laxity and knee stiffness with the interference screw was not significantly different from that with the high-stiffness distal methods. CONCLUSION: In the human knee, the use of high-stiffness fixation devices placed distal to the joint line restored anterior laxity and knee stiffness as well as joint line fixation with an interference screw at implantation. CLINICAL RELEVANCE: The stiffness provided by each method of fixation should be considered along with the length of the graft when determining anterior laxity and knee stiffness.
BACKGROUND: Fixation of an anterior cruciate ligament graft at the joint line with an interference screw restores anterior laxity better than low-stiffness distal fixation with double staples and sutures tied to a post at implantation in porcine bone. HYPOTHESIS: Fixation of an anterior cruciate ligament graft with a high-stiffness distal fixation device restores anterior laxity and knee stiffness as well as joint line fixation with an interference screw in human bone. STUDY DESIGN: Controlled laboratory study. METHODS: Eleven cadaveric knees with foam reinforcement of the bone were reconstructed with a double-looped tendon graft and fixed with an interference screw and 3 high-stiffness methods of fixation (tandem washer, WasherLoc, and WasherLoc with bone dowel). Anterior laxity at 225 and 110 N of anterior load and knee stiffness were measured at 0 degrees , 30 degrees , 60 degrees , 90 degrees , and 120 degrees of flexion with a 6 degrees of freedom load application system. RESULTS: The increase in anterior laxity and knee stiffness with the interference screw was not significantly different from that with the high-stiffness distal methods. CONCLUSION: In the human knee, the use of high-stiffness fixation devices placed distal to the joint line restored anterior laxity and knee stiffness as well as joint line fixation with an interference screw at implantation. CLINICAL RELEVANCE: The stiffness provided by each method of fixation should be considered along with the length of the graft when determining anterior laxity and knee stiffness.