Comparing Stability of Different Single- and Double-Bundle Anterior Cruciate Ligament Reconstruction Techniques: A Cadaveric Study Using Navigation

Purpose: The objective of this study was to analyze 2 different single-bundle anterior cruciate ligament (ACL) reconstruction procedures and compare their ability to reduce the pivot-shift phenomenon with an anatomic double-bundle (DB) technique. Methods: Twelve fresh-frozen cadaveric hip-to-toe lower extremity specimens were used. ACL reconstructions were performed by conventional single-bundle, anteromedial (AM) single-bundle, and DB techniques. Anterior tibial translation was measured in the intact knee, ACL-deficient knee, and the 3 ACL reconstructions in response to a Lachman test and a mechanized pivot-shift test. A surgical navigation system (Praxim Medivision, Grenoble, France) simultaneously tracked kinematics. Results: Intact knees were clinically graded as grade 0 (n = 12). ACL-deficient knees were graded as grade 1 (n = 10) and grade 2 (n = 2). With a mechanized pivot-shift test, anterior tibial translation was 1.7 +/- 3.0 mm, 9.7 +/- 3.8 mm, 4.4 +/- 1.0 mm, 1.8 +/- 1.5 mm, and -1.7 +/- 3.3 mm for intact knees, ACL-deficient knees, conventional technique, AM technique, and DB technique, respectively. There was a significant difference between the DB technique and both single-bundle techniques tested (P < .05). Conclusions: The model used represents an isolated ACL injury without concomitant injury to the capsuloligamentous restraints or menisci. However, during the pivot shift, neither type of single-bundle ACL reconstruction stabilized the knee to the same degree as the DB ACL reconstruction. Clinical Relevance: In this cadaveric model a DB repair offers great anterior and rotational stability. Although this study suggests that the DB technique is biomechanically superior to a single-bundle technique using traditional transtibial tunnel positions, there appear to be minimal differences in knee kinematics during stability testing with the DB technique versus an AM graft position. Indeed, compared with the AM position alone, the DB technique "overconstrained" the kinematics of the knee during a pivoting maneuver at time zero in a cadaveric model with an isolated ACL injury.