Conventional Single-bundle Reconstruction Research Articles

Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Was Superior to Conventional Single-Bundle Reconstruction

Hosalkar, Harish S. MD, MBMS(Orth), FCPS(Orth), DNB(Orth)1; Pandya, Nirav K. MD1; Wenger, Dennis R. MD1 Author Information

Prospective Randomized Clinical Evaluation of Conventional Single-Bundle, Anatomic Single-Bundle, and Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

Background: Three different techniques of anterior cruciate ligament (ACL) reconstruction—conventional (transtibial) single bundle (CSB), anatomic single bundle (ASB), and anatomic double bundle (ADB)—have been described. Purpose: To determine if double-bundle reconstruction is needed to restore rotational stability or if anatomic placement of a single bundle can yield similar results. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: From December 2005 to December 2007, 320 patients were prospectively randomized into 3 groups: ADB, ASB, and CSB reconstruction. The average follow-up was 51.15 months (range, 39-63 months). At the final follow-up, 281 patients were available. In all groups, hamstring tendons were used with suspensory fixation on the femoral side and bioabsorbable interference screw fixation on the tibial side. The outcomes were evaluated by an independent blinded observer using the Lysholm score and subjective International Knee Documentation Committee (IKDC) form. The KT-1000 arthrometer was used to evaluate anteroposterior stability, and the pivot-shift test was used to determine rotational stability. Results: Anatomic single-bundle reconstruction resulted in better anteroposterior and rotational stability than CSB reconstruction (average side-to-side difference for anterior tibial translation was 1.6 mm in the ASB group vs 2.0 mm in the CSB group; P = .002). Negative pivot shift was 66.7% vs 41.7% (P = .003). In other parameters, the differences between groups were not statistically significant. The results of the ADB group were also superior to the ASB group for anteroposterior and rotational stability (average side-to-side difference for anterior tibial translation was 1.2 mm in the ADB group vs 1.6 mm in the ASB group; P = .002). Negative pivot shift was 93.1% vs 66.7%, respectively (P < .001), and range of motion was also significantly different (P = .005). The Lysholm score was 90.9, 91.8, and 93.0 in the CSB, ASB, and ADB groups, respectively. The difference was significant only when we compared ADB and CSB (P = .025). Subjective IKDC scores were 90.2, 90.6, and 92.1 in the CSB, ASB, and ADB groups, respectively. The difference was not significant. Conclusion: Anatomic double-bundle ACL reconstruction is significantly superior to conventional single-bundle ACL reconstruction and better than anatomic single-bundle reconstruction. Anatomic single-bundle reconstruction was superior to conventional single-bundle reconstruction. However, these differences are small and may not be clinically relevant.

Single-Tunnel Double-Bundle Anterior Cruciate Ligament Reconstruction with Anatomical Placement of Hamstring Tendon Graft

Background Anatomical reconstruction techniques that can restore normal joint kinematics without increasing surgical complications could potentially improve clinical outcomes and help manage anterior cruciate ligament injuries more efficiently. Hypothesis Single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft can more closely restore normal knee anterior-posterior, medial-lateral, and internal-external kinematics than can conventional single-bundle anterior cruciate ligament reconstruction. Study Design Controlled laboratory study. Methods Kinematic responses after single-bundle anterior cruciate ligament reconstruction and single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft were compared with the intact knee in 9 fresh-frozen human cadaveric knee specimens using a robotic testing system. Kinematics of each knee were determined under an anterior tibial load (134 N), a simulated quadriceps load (400 N), and combined torques (10 N·m valgus and 5 N·m internal tibial torques) at 0°, 15°, 30°, 60°, and 90° of flexion. Results Anterior tibial translations were more closely restored to the intact knee level after single-tunnel double-bundle reconstruction with anatomical placement of hamstring tendon graft than with a single-bundle reconstruction under the 3 external loading conditions. Under simulated quadriceps load, the mean internal tibial rotations after both reconstructions were lower than that of the anterior cruciate ligament—intact knee with no significant differences between these 3 knee conditions at 0° and 30° of flexion (P > .05). The increased medial tibial shifts of the anterior cruciate ligament—deficient knees were restored to the intact level by both reconstruction techniques under the 3 external loading conditions. Conclusion Single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft can better restore the anterior knee stability compared with a conventional single-bundle reconstruction. Both reconstruction techniques are efficient in restoring the normal medial-lateral stability but overcorrect the internal tibial rotations. Clinical Relevance Single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft could provide improved clinical outcomes over a conventional single-bundle reconstruction.

Changes in the Length of Virtual Anterior Cruciate Ligament Fibers during Stability Testing

Background Conventional tunnel positions for single-bundle (SB) transtibial anterior cruciate ligament (ACL) reconstruction are located in the posterolateral (PL) tibial footprint and the anteromedial (AM) femoral footprint, resulting in an anatomic mismatch graft that is more vertical than native fibers. This vertical mismatch position may significantly influence the ability of an ACL graft to stabilize the knee. Hypothesis Anatomic ACL fibers undergo a greater change in length during anterior translation and internal rotation than a conventional SB reconstruction from the PL tibial footprint to the AM femoral footprint. Study Design Controlled laboratory study. Methods The Praxim ACL Surgetics navigation system was used to acquire kinematic data during a flexion/extension cycle and to register all points within the ACL footprint from 5 fresh-frozen cadaveric knees. Virtual fibers were placed in the center of the AM and PL bundles as well as central and conventional SB positions. After transection of the ACL, the absolute length change and apparent strain of the fibers were computed for each knee during the Lachman and anterior drawer tests and internal rotation at 0° and 30° of flexion. Results Each of the anatomic fibers (AM, PL, and central) had more elongation and apparent strain than the conventional SB fiber during the Lachman maneuver. During the anterior drawer test, the AM and central (but not the PL) fibers lengthened significantly more and the AM had more apparent strain than the conventional SB fiber. During internal rotation at 0° and 30° of flexion, anatomic fibers elongated significantly more than the conventional fiber. Except for the AM fiber with the knee at full extension, apparent strain was greater in all anatomic fibers than in the conventional SB fiber during internal rotation maneuvers. Conclusion In ACL-deficient cadaveric knees, anatomic fibers undergo greater elongation and apparent strain in response to anterior translation and internal rotation maneuvers than a conventional SB graft. Because of their optimal orientation, anatomic fibers may resist pathologic anterior translation and internal rotation more than the conventional SB position. Clinical Relevance Conventional placement of a single-bundle graft results in suboptimal changes in fiber length and strain, suggesting that alternatives such as anatomic placement of an SB graft or double-bundle reconstruction may result in greater control of translation and rotation.

Double-bundle ACL Reconstruction Can Improve Rotational Stability

Double-bundle anterior cruciate ligament (ACL) reconstruction reproduces anteromedial and posterolateral bundles, and thus has theoretical advantages over conventional single-bundle reconstruction in controlling rotational torque in vitro. However, its superiority in clinical practice has not been proven. We analyzed rotational stability with three reconstruction techniques in 60 consecutive patients who were randomly divided into three groups (double-bundle, anteromedial single-bundle, posterolateral single-bundle). In the reconstructive procedure, the hamstring tendon was harvested and used as a free tendon graft. Followup examinations were performed 1 year after surgery. Anteroposterior laxity of the knee was examined with a KT-1000 arthrometer, whereas rotatory instability, as elicited by the pivot shift test, was assessed using a new measurement system incorporating three-dimensional electromagnetic sensors. Routine clinical evaluations, including KT examination, demonstrated no differences among the three groups. However, using the new measurement system, patients with double-bundle ACL reconstruction showed better pivot shift control of complex instability than patients with anteromedial and posterolateral single-bundle reconstruction.

Anterior Cruciate Ligament Double-Bundle Reconstruction With Hamstring Tendon Autografts

The anterior cruciate ligament (ACL) surgical technique via a 5-strand hamstring tendon autograft is designed with a conventional single-bundle reconstruction that has shown favorable results and an additional posterolateral (PL) bundle reconstruction. The conventional single-tunnel technique is performed for the tibial tunnel, and the double-tunnel technique is performed for the femoral tunnel. The anteromedial (AM) femoral tunnel is prepared with 1 mm of the posterior femoral cortex being left over the top at the 11- to 1-o’clock position. The PL femoral tunnel is prepared with the outside-in technique by use of a 4.5-mm cannulated reamer. The AM bundle is fixed with a rigid fixation system on the femoral side, and the PL bundle is fixed to tie with the miniplate from the outside femur. A double-bundle reconstruction with 5-strand hamstring autografts, in conjunction with a conventional AM bundle and an additional PL bundle, seems to be a very effective method for the treatment of ACL instabilities. Although the long-term clinical outcome of the procedure is yet to be determined, complications including graft impingement, limitation in range of motion, and residual instability have not been observed to date in the first 38 patients who have undergone our technique.