Background: In several anatomic single-bundle anterior cruciate ligament (ACL) reconstruction (ASB-ACLR) procedures, the femoral and tibial tunnel apertures are created at different locations within the native ACL attachment area.
Hypothesis: Graft length changes during knee motion will be different among ASB-ACLR procedures with different femoral and tibial tunnel aperture locations.
Study design: Controlled laboratory study.
Methods: A total of 12 cadaveric knees were used in this study. In each knee, 4 and 3 thin tunnels were created within the ACL attachment area on the femur and the tibia, respectively. Using 1 of 5 different combinations of femoral and tibial tunnel aperture location, 5 ASB-ACLRs were performed on each knee. In each reconstruction approach, a strong thread was used in place of the tendon graft, and the tibial graft end was tethered to a custom-made isometric positioner at 0° of knee flexion, with an approximately 12-N load applied to the thread. Then, each specimen underwent 5 cycles of knee flexion-extension motion in a range between 0° and 120°, and graft length changes were determined for each SB-ACLR approach.
Results: The length changes of the graft were significantly different among the 5 ASB-ACLRs. The maximum length change values of the 3 grafts that were implanted between the femoral and tibial centers of the posterolateral bundle attachments or implanted into the femoral tunnel created at the center of the fanlike extension fiber attachment were significantly greater than those of the graft implanted between the centers of the anteromedial bundle attachments (P < .0001) and of the graft implanted between the centers of the whole ACL attachments (P < .0001).
Conclusion: The length changes of the graft during knee motion were significantly different among the 5 ASB-ACLR approaches, even though all of the tunnel apertures were created within the femoral and tibial attachments of the native ACL.
Clinical relevance: The grafts in the first 3 graft locations may be so relaxed during knee flexion that they cannot resist anterior drawer loads exerted on the tibia.
Keywords: ACL; anatomic reconstruction; biomechanics; graft isometry; graft length; single bundle.
Conflict of interest statement
One or more of the authors has declared the following potential conflict of interest or source of funding: The threads and fixation devices used in this study were donated by Smith & Nephew Endoscopy Japan. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
Comparison of 2 Femoral Tunnel Locations in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction: A Biomechanical StudyMD Driscoll et al. Arthroscopy 28 (10), 1481-9. PMID 22796141.Anatomic single-bundle ACL reconstruction performed with the femoral tunnel placed through the AM portal restores translational and rotational knee stability to an extent …
Comparison of Knee Kinematics After Single-Bundle Anterior Cruciate Ligament Reconstruction via the Medial Portal Technique With a Central Femoral Tunnel and an Eccentric Femoral Tunnel and After Anatomic Double-Bundle Reconstruction: A Human Cadaveric StudyM Herbort et al. Am J Sports Med 44 (1), 126-32. PMID 26574601.The SB-central technique restored intact knee kinematics more closely than did SB-AM reconstruction at time zero. There were no differences in knee kinematics between the …
Femoral and Tibial Tunnel Positioning on Graft Isometry in Anterior Cruciate Ligament Reconstruction: A Cadaveric StudyJO Smith et al. J Orthop Surg (Hong Kong) 22 (3), 318-24. PMID 25550010.None of the ACL graft positions was isometric. Anatomic ACL positioning resulted in comparable anisometry to the native ACL. The minimum distance for all graft positions …
Changes in the Length of Virtual Anterior Cruciate Ligament Fibers During Stability Testing: A Comparison of Conventional Single-Bundle Reconstruction and Native Anterior Cruciate LigamentRH Brophy et al. Am J Sports Med 36 (11), 2196-203. PMID 18669985.In ACL-deficient cadaveric knees, anatomic fibers undergo greater elongation and apparent strain in response to anterior translation and internal rotation maneuvers than …
Femoral and Tibial Graft Tunnel Parameters After Transtibial, Anteromedial Portal, and Outside-In Single-Bundle Anterior Cruciate Ligament ReconstructionM Osti et al. Am J Sports Med 43 (9), 2250-8. PMID 26138734.The AMP and OI surgical techniques were superior in positioning the ACL femoral tunnel at the center of the native ACL attachment site compared with the TT technique. An …
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