Effect of posterolateral bundle graft fixation angles on graft tension curves and load sharing in double-bundle anterior cruciate ligament reconstruction using a transtibial drilling technique.
OBJECTIVE
To evaluate the effect of posterolateral bundle (PLB) graft fixation angles on graft tension curves and load sharing between the anteromedial bundle (AMB) and the PLB in double-bundle anterior cruciate ligament (ACL) reconstruction.


METHODS
Twenty-four patients who underwent double-bundle ACL reconstruction were included in this study. AMB and PLB were provisionally fixed to a graft tensioning system during surgery. The graft fixation settings were as follows: (1) AMB at 20° and PLB at 0° (A20P0), (2) AMB at 20° and PLB at 20° (A20P20), and (3) AMB at 20° and PLB at 45° (A20P45). Bundle tension was recorded during knee flexion-extension and in response to anterior or rotatory loads. A pivot-shift test, as well as factors affecting the residual pivot-shift, was also evaluated.


RESULTS
A20P45 created reciprocal tension curves and load sharing, in which the tension in both bundles was equivalent during flexion-extension and during each loading test at 30°. In A20P0, the tension of the AMB was constantly higher than that of the PLB. Seven patients showed grade 1 pivot-shift phenomenon in A20P0, whereas no patient showed a positive pivot-shift at other settings. Larger tension reduction of the PLB between 0° and 30° and smaller load sharing of the PLB were significant factors affecting residual pivot-shift.


CONCLUSIONS
In double-bundle ACL reconstruction, fixation of the AMB at 20° and the PLB at 45° created reciprocal tension curves and load sharing between the bundles. Fixation of the AMB at 20° and the PLB at 0° led to insufficient tension in the PLB, resulting in a residual pivot-shift phenomenon in 7 of 24 patients.


METHODS
Level IV, therapeutic case series.
Department of Orthopaedic Surgery, Tokyo Medical and Dental University Hospital of Medicine, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. koga.orj@tmd.ac.jp
Hideyuki
H
Koga
Takeshi
T
Muneta
Kazuyoshi
K
Yagishita
Young-Jin
YJ
Ju
Tomoyuki
T
Mochizuki
Masafumi
M
Horie
Tomomasa
T
Nakamura
Atsushi
A
Okawa
Ichiro
I
Sekiya
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D013710:Tendons / Q000503:physiopathology / Q000637:transplantation; D014182:Transplantation, Autologous; D055815:Young Adult