ACL double-bundle reconstruction with one tibial tunnel provides equal stability compared to two tibial tunnels.
OBJECTIVE
The purpose of this study was to investigate whether an anterior cruciate ligament (ACL) double-bundle reconstruction with one tibial tunnel displays the same in vitro stability as a conventional double-bundle reconstruction with two tibial tunnels when using the same tensioning protocol.


METHODS
In 11 fresh-frozen cadaveric knees, ACL double-bundle reconstruction with one and two tibial tunnels was performed. The two grafts were tightened using 80 N in different flexion angles (anteromedial-bundle at 60° and posterolateral-bundle at 15°). Anterior tibial translation (134 N) and translation with combined rotatory and valgus loads (10 Nm valgus stress and 4 Nm internal tibial torque) were determined at 0°, 30°, 60° and 90° flexion. Measurements were taken in intact ACL, resected ACL, three-tunnel reconstruction and four-tunnel reconstruction. Additionally, the tension on the grafts was determined. Student's t test was performed for statistical analysis of the related samples. Significance was set at p < 0.017 according to Bonferroni correction.


RESULTS
The two reconstructive techniques displayed no significant differences in comparison with the intact ACL in anterior tibial translation at 0°, 60° and 90° of flexion. The same results were obtained for the anterior tibial translation with a combined rotatory load at 60° and 90°. When directly comparing both reconstructive techniques, there were no significant differences for the anterior tibial translation and combined rotatory load at all flexion angles. The measured tension on grafts displayed similar load sharing between both bundles. Except at full extension, both grafts displayed a significantly different tension increase under anterior tibial translation for both techniques (p = 0.0086).


CONCLUSIONS
Tightening both bundles in ACL double-bundle reconstruction with one or two tibial tunnels in different flexion angles achieved comparable restoration of stability, although there was different load sharing on the bundles. With regard to individualized ACL reconstruction, the double-bundle technique with one tibial tunnel offers a possibility to address small tibial insertion sites without compromising the advantages of a double-bundle procedure.
Department for Orthopedic Trauma, Hand and Reconstructive Surgery, Center of Surgery, University of Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany. b.drews@me.com.
Björn Holger
BH
Drews
Center of Musculoskeletal Research, Institute of Orthopedic Research and Biomechanics, University of Ulm, Helmholtzstraße 14, 89081, Ulm, Germany.
Andreas Martin
AM
Seitz
Sportklinik Stuttgart GmbH, Taubenheimstraße 8, 70734, Stuttgart, Germany.
Jochen
J
Huth
Sportklinik Stuttgart GmbH, Taubenheimstraße 8, 70734, Stuttgart, Germany.
Gerhard
G
Bauer
Center of Musculoskeletal Research, Institute of Orthopedic Research and Biomechanics, University of Ulm, Helmholtzstraße 14, 89081, Ulm, Germany.
Anita
A
Ignatius
Center of Musculoskeletal Research, Institute of Orthopedic Research and Biomechanics, University of Ulm, Helmholtzstraße 14, 89081, Ulm, Germany.
Lutz
L
Dürselen
D000368:Aged; D016118:Anterior Cruciate Ligament / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D008875:Middle Aged; D016059:Range of Motion, Articular; D013977:Tibia / Q000601:surgery*; D019415:Torque
ACL reconstruction; Double-bundle; One tibial tunnel; Three-tunnel technique