Author's Reply

Abstract

We welcome the comments of Dr. Fu and colleagues regarding our article and are very grateful for their interest and enthusiasm. First, we totally agree that we should try to perform an anatomic ACL reconstruction in both single-bundle and double-bundle reconstructions with the tunnel placed in the footprint of the ACL. However, we still cannot reconstruct an injured ACL as the same as a normal and preinjured state. There are many limitations, such as graft material and technical aspects, that prevent achieving such results. Second, to evaluate the technique used in ACL reconstruction studies, it is beneficial to have a detailed explanation of surgical technique and use intraoperative and postoperative imaging, including radiographs, magnetic resonance imaging, or computed tomography, which can be useful in assessing anatomic positioning. We completely agree that 3-dimensional computed tomography or magnetic resonance imaging would be useful in accurately evaluating tunnel placement, but we did not use these in our study because of economic and some other unrelated problems. Third, we decided to select patients for single-bundle or double-bundle reconstruction sequentially based on admission to the hospital. If we had selected the single- or double-bundle procedure based on the size of the notch or the ACL insertion site, it would have been a selective indication for the reconstruction of the ACL by the single- or double-bundle method. The results of our study showed no significant differences between the single- and double-bundle procedures. Perhaps more patients with a variety of factors need to be studied to determine which patients truly require a double-bundle ACL reconstruction. We believe that single-bundle reconstruction can restore the same knee function as a double-bundle technique or normal ACL. The central location of the tunnel placement, between the anteromedial bundle and posterolateral bundle, can restore the nearly normal anterior translation to the knee under anterior rotated normal kinematics, at 30° and 60° of knee flexion.1Ho J.Y. Gardiner A. Shah V. Steiner M.E. Equal kinematics between central anatomic single-bundle and double-bundle anterior cruciate ligament reconstructions.Arthroscopy. 2009; 25: 464-472Abstract Full Text Full Text PDF PubMed Scopus (111) Google Scholar Regarding double-bundle reconstruction, we have to obtain more accurate positioning of the tunnels. There are differences in tunnel positions as shown by studies with radiologic or computed tomography images.2Colombet P. Robinson J. Christel P. et al.Morphology of anterior cruciate ligament attachments for anatomic reconstruction: A cadaveric dissection and radiographic study.Arthroscopy. 2006; 22: 984-992Abstract Full Text Full Text PDF PubMed Scopus (340) Google Scholar, 3Zantop T. Schumacher T. Schanz S. Raschke M.J. Petersen W. Double-bundle reconstruction cannot restore intact knee kinematics in the ACL/LCL-deficient knee.Arch Orthop Trauma Surg. 2010; 130: 1019-1026Crossref PubMed Scopus (23) Google Scholar, 4Forsythe B. Kopf S. Wong A.K. et al.The location of femoral and tibial tunnels in anatomic double-bundle anterior cruciate ligament reconstruction analyzed by three-dimensional computed tomography models.J Bone Joint Surg Am. 2010; 92: 1418-1426Crossref PubMed Scopus (256) Google Scholar, 5Tsukada H. Ishibashi Y. Tsuda E. Fukuda A. Toh S. Anatomical analysis of the anterior cruciate ligament femoral and tibial footprints.J Orthop Sci. 2008; 13: 122-129Abstract Full Text PDF PubMed Scopus (144) Google Scholar With regard to surgical technique, the transtibial technique has some problems. To make the tunnels more horizontal in the femur, which we mentioned in our “Discussion” section, we have recently used an accessory low medial portal to create anatomic femoral and tibial tunnels. However, when using a low anterior-medial portal, when knee flexion is more than 120°, it is difficult to obtain good visualization. Besides that, the femoral tunnel aperture, especially the tunnel orifice, may be more oblique in shape. Therefore we suggest the creation of a far-medial accessory low anterior-medial portal (about 2 cm medial to the medial border of the patellar tendon instead of the low medial portal) to make a less oblique femoral tunnel orifice.6Nishimoto K. Kuroda R. Mizuno K. et al.Analysis of the graft bending angle at the femoral tunnel aperture in anatomic double bundle anterior cruciate ligament reconstruction: A comparison of the transtibial and the far anteromedial portal technique.Knee Surg Sports Traumatol Arthrosc. 2009; 17: 270-276Crossref PubMed Scopus (76) Google Scholar To achieve good visualization, we use a clean transparent plastic tube over the reamer, which acts as outflow, protects the medial femoral cartilage, as well as the ACL remnant (if we want to preserve it for proprioception or tension it with pullout sutures), and allows easy washout of the bone debris (Video 1, available at www.arthroscopyjournal.org). For output drainage, we make another high anterior medial portal, which is helpful to obtain a clear arthroscopic visual field, especially with the knee at 120° of flexion. We appreciate the comments of Dr. Fu and colleagues. Further study is needed to continue improving this procedure and determine the optimal methodology. Download .mpg (114.98 MB) Help with mpg files Video 1A clean transparent plastic tube over the reamer gives us clear visual field during surgery, as well as protects the medial femoral cartilage and ACL remnant. Note: To access the video illustration accompanying this letter, visit the November issue of Arthroscopy at www.arthroscopyjournal.org. Principle Considerations in Anatomic ACL ReconstructionArthroscopyVol. 26Issue 11PreviewWith great interest, we read the article by Park et al.1 entitled “Outcome of arthroscopic single-bundle versus double-bundle reconstruction of the anterior cruciate ligament: A preliminary 2-year prospective study.” In this interesting article the researchers studied the preoperative data after single-bundle ACL reconstruction and compared these with the data after double-bundle ACL reconstruction. In addition, the postoperative clinical outcome was assessed by International Knee Documentation Committee score, Orthopaedische Arbeitsgruppe Knie score, and Tegner activity scale. Full-Text PDF