Tensioning in Double‐Bundle ACL Reconstruction

In the June issue of Arthroscopy, Asagumo et al.1Asagumo H. Kimura M. Kobayashi Y. Taki M. Takagishi K. Anatomic reconstruction of the anterior cruciate ligament using double-bundle hamstring tendons: Surgical techniques, clinical outcomes, and complications.Arthroscopy. 2007; 23: 602-609Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar report a clinical outcome study of single-bundle versus double-bundle anterior cruciate ligament (ACL) reconstructions. They state that these 2 procedures have no significant difference in outcome and that the double-bundle group has worse range of motion (ROM) and a higher complication rate than the single-bundle group. Although I respect their efforts and would like to congratulate them on the publication, I would like to point out a few technical points that could explain many of their findings.First, the authors fixed both bundles at 30° of flexion with a tensioner. This method over-constrains the posterolateral (PL) bundle, which is tightest in extension.2Miura K. Woo S.L. Brinkley R. Fu Y.C. Noorani S. Effects of knee flexion angles for graft fixation on force distribution in double-bundle anterior cruciate ligament grafts.Am J Sports Med. 2006; 34: 577-585Crossref PubMed Scopus (70) Google Scholar This would certainly explain why they reported 5 PL bundle–only ruptures as well as the extension deficits in the double-bundle cases. On the basis of biomechanical studies, we tension the anteromedial (AM) bundle in 60° of flexion and the PL bundle in 0° to 10°.3Gabriel M.T. Wong E.K. Woo S.L. Yagi M. Debski R.E. Distribution of in situ forces in the anterior cruciate ligament in response to rotatory loads.J Orthop Res. 2004; 22: 85-89Crossref PubMed Scopus (515) Google Scholar Second, the authors do not explain exactly how they perform their femoral tunnel drilling. Were these tunnels drilled through tibial tunnels or portals? We have found that if the femoral tunnels are drilled primarily through the AM tibial tunnel as with traditional transtibial approaches, the resulting femoral tunnels are high and outside the native insertion site of the ACL in more than 50% of the cases. This nonanatomic femoral tunnel placement may also have contributed to their inferior ROM and increased number of failures in the double-bundle group. We use a 3-portal technique for anatomic femoral and tibial tunnel placement.4Cohen S.B. Fu F.H. Three-portal technique for anterior cruciate ligament reconstruction: Use of a central medial portal.Arthroscopy. 2007; 23 (Available online at www.arthroscopyjournal.org.): 325.e1-325.e5Abstract Full Text Full Text PDF Scopus (102) Google Scholar Finally, we have found that the timing of return of ROM is critical. In our double-bundle patients, we have found improved ROM in the early postoperative period (<3 months) compared with our single-bundle patients. Early postoperative ROM signals anatomic graft placement, whereas most improvement in ROM after 6 months is more indicative of graft stretching.5Tashman S. Kolowich P. Collon D. Anderson K. Anderst W. Dynamic function of the ACL-reconstructed knee during running.Clin Orthop Relat Res. 2007; 454: 66-73Crossref PubMed Scopus (270) Google Scholar Thus the authors’ observed limitations in ROM may represent nonanatomic tunnel placement and tunnel mismatch.In conclusion, I recognize that double-bundle ACL reconstruction is a technically demanding procedure, and I, too, have experienced a learning curve. However, if a double-bundle ACL reconstruction is performed with the proper surgical technique (i.e., correct anatomic position and tension), the patient should theoretically exhibit better ROM, stability, and kinematics than the patient undergoing a single-bundle procedure because of restoration of anatomy. I praise the authors for their efforts, but I believe that it is not accurate to formulate their conclusions based on their technique and data. In the June issue of Arthroscopy, Asagumo et al.1Asagumo H. Kimura M. Kobayashi Y. Taki M. Takagishi K. Anatomic reconstruction of the anterior cruciate ligament using double-bundle hamstring tendons: Surgical techniques, clinical outcomes, and complications.Arthroscopy. 2007; 23: 602-609Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar report a clinical outcome study of single-bundle versus double-bundle anterior cruciate ligament (ACL) reconstructions. They state that these 2 procedures have no significant difference in outcome and that the double-bundle group has worse range of motion (ROM) and a higher complication rate than the single-bundle group. Although I respect their efforts and would like to congratulate them on the publication, I would like to point out a few technical points that could explain many of their findings. First, the authors fixed both bundles at 30° of flexion with a tensioner. This method over-constrains the posterolateral (PL) bundle, which is tightest in extension.2Miura K. Woo S.L. Brinkley R. Fu Y.C. Noorani S. Effects of knee flexion angles for graft fixation on force distribution in double-bundle anterior cruciate ligament grafts.Am J Sports Med. 2006; 34: 577-585Crossref PubMed Scopus (70) Google Scholar This would certainly explain why they reported 5 PL bundle–only ruptures as well as the extension deficits in the double-bundle cases. On the basis of biomechanical studies, we tension the anteromedial (AM) bundle in 60° of flexion and the PL bundle in 0° to 10°.3Gabriel M.T. Wong E.K. Woo S.L. Yagi M. Debski R.E. Distribution of in situ forces in the anterior cruciate ligament in response to rotatory loads.J Orthop Res. 2004; 22: 85-89Crossref PubMed Scopus (515) Google Scholar Second, the authors do not explain exactly how they perform their femoral tunnel drilling. Were these tunnels drilled through tibial tunnels or portals? We have found that if the femoral tunnels are drilled primarily through the AM tibial tunnel as with traditional transtibial approaches, the resulting femoral tunnels are high and outside the native insertion site of the ACL in more than 50% of the cases. This nonanatomic femoral tunnel placement may also have contributed to their inferior ROM and increased number of failures in the double-bundle group. We use a 3-portal technique for anatomic femoral and tibial tunnel placement.4Cohen S.B. Fu F.H. Three-portal technique for anterior cruciate ligament reconstruction: Use of a central medial portal.Arthroscopy. 2007; 23 (Available online at www.arthroscopyjournal.org.): 325.e1-325.e5Abstract Full Text Full Text PDF Scopus (102) Google Scholar Finally, we have found that the timing of return of ROM is critical. In our double-bundle patients, we have found improved ROM in the early postoperative period (<3 months) compared with our single-bundle patients. Early postoperative ROM signals anatomic graft placement, whereas most improvement in ROM after 6 months is more indicative of graft stretching.5Tashman S. Kolowich P. Collon D. Anderson K. Anderst W. Dynamic function of the ACL-reconstructed knee during running.Clin Orthop Relat Res. 2007; 454: 66-73Crossref PubMed Scopus (270) Google Scholar Thus the authors’ observed limitations in ROM may represent nonanatomic tunnel placement and tunnel mismatch. In conclusion, I recognize that double-bundle ACL reconstruction is a technically demanding procedure, and I, too, have experienced a learning curve. However, if a double-bundle ACL reconstruction is performed with the proper surgical technique (i.e., correct anatomic position and tension), the patient should theoretically exhibit better ROM, stability, and kinematics than the patient undergoing a single-bundle procedure because of restoration of anatomy. I praise the authors for their efforts, but I believe that it is not accurate to formulate their conclusions based on their technique and data. Anatomic Reconstruction of the Anterior Cruciate Ligament Using Double-Bundle Hamstring Tendons: Surgical Techniques, Clinical Outcomes, and ComplicationsArthroscopyVol. 23Issue 6PreviewPurpose: The objective of the study was to retrospectively compare the clinical outcomes of anatomic double-bundle anterior cruciate ligament reconstruction via hamstring tendons with single-bundle reconstruction between April 2002 and March 2004. Methods: We retrospectively reviewed 123 consecutive patients, 71 of whom underwent double-bundle reconstruction and 52 of whom underwent single-bundle reconstruction. The same postoperative rehabilitation protocol was used for all patients. The patients were followed up for a mean of 33 months. Full-Text PDF Authors’ ReplyArthroscopyVol. 23Issue 9PreviewI read with interest the letter to the Editor by Dr. Freddy Fu to our recently published article. In our article we presented some difficulties and complications of a double-bundle procedure that we experienced during 2002 to 2004 at the beginning of our use of this procedure.1 At that time, a fixed angle had not yet been realized when creating a completely new anatomically positioned posterolateral (PL) femoral tunnel. Now, however, we fix both bundles at 10° of flexion at the same time. As for femoral tunnel drilling, we drill the anteromedial (AM) femoral tunnel through the AM tibial tunnel and the PL femoral tunnel through the PL tibial tunnel. Full-Text PDF