Purpose
First, we aimed to investigate the ability of a single bone–patellar tendon–bone graft
placed in the anatomic center of the femoral and tibial attachment sites to restore
normal tibiofemoral compartment translations and tibial rotation. Second, we aimed
to investigate what combination of anterior load and internal rotation torque applied
during a pivot-shift test produces maximal anterior tibiofemoral subluxations.
Methods
We used a 6-df robotic simulator to test 10 fresh-frozen cadaveric specimens under anterior cruciate
ligament (ACL)–intact, ACL-sectioned, and ACL-reconstructed conditions measuring anterior
translations of the medial, central, and lateral tibiofemoral compartments and degrees
of tibial rotation. Specimens were loaded under Lachman, anterior limit, and internal
rotation conditions, as well as 3 different pivot-shift conditions.
Results
On ACL sectioning, compartment translations in the Lachman and 3 pivot-shift tests
increased significantly and were restored to ACL-intact values after single-graft
ACL reconstruction. In the pivot-shift tests, the single graft restored lateral and
medial compartment translations (e.g., group 3, within 1.3 ± 0.6 mm and 0.8 ± 0.6
mm, respectively, of the ACL-intact state and internal rotation within 0.7° ± 1.2°).
Anterior subluxation of the medial compartment during pivot-shift loading was reduced
when internal rotation torque was increased from 1 to 5 Nm (P < .0001).
Conclusions
A single-graft ACL reconstruction performed at the central femoral and tibial ACL
attachment sites restored anterior-posterior translation and tibial rotation motion
limits. In addition, rotational knee stability as defined by tibiofemoral compartment
translations was restored under all simulated pivot-shift testing conditions.
Clinical Relevance
This study provides in vitro evidence to support the clinical use of single-graft
ACL reconstructions in restoring tibiofemoral compartment translations. It also shows
the advantage of describing ACL insufficiency in terms of medial and lateral compartment
subluxations as compared with the common approach of describing changes in central
tibial translations and rotations.
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Article info
Publication history
Published online: May 29, 2015
Accepted:
April 9,
2015
Received:
May 6,
2014
Footnotes
The authors report the following potential conflict of interest or source of funding: This work was supported by the Jewish Hospital Foundation, Cincinnati, Ohio.
Identification
Copyright
© 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
