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Editorial Commentary: It Is All About How One Defines the Anatomy
Editorial Commentary: It Is All About How One Defines the Anatomy
Abstract: Radiographic landmarks as defined by the original definition of the anterolateral ligament at the knee are provided.
See related article on page 844
T
he article by Heckmann et al.1 strives to further define the radiographic landmarks for identifying the anterolateral ligament of the knee. I believe that this type of study is useful because all of our previous works in this area around the knee2-6 have proved to be very helpful for the intraoperative identification of ligament attachment landmarks and also for the postoperative identification of reconstruction tunnels to determine if these structures have been anatomically repositioned. Overall, I believe that the methods for the study were performed well. The locations of the radiopaque markers were checked by a minimum of 4 authors, and the radiographic calibration of the distances was calculated. I have particularly found the issue of radiographic calibration to be very important because placing the calibration marker either on top or under the specimen in our hands was found to change the radiographic magnification distances by 10% or more. This brings us to the topic of the anatomy. We have recently worked on an anterolateral ligament anatomy publication7 with Steven Claes, whose original anatomy article on formalin-preserved knees8 was referenced for the landmarks that Heckmann et al.1 have noted for the positioning of their radiographic markers. In our study, which was performed on fresh-frozen knees, we found that the anterolateral ligament attaches posterior to the lateral epicondyle, with some specimens concurrently having some attachment fibers that coursed to the lateral epicondyle. The more posterior attachment site of the anterolateral ligament defined in our recent anatomy article7 generally fits
Ó 2016 by the Arthroscopy Association of North America 0749-8063/16207/$36.00 http://dx.doi.org/10.1016/j.arthro.2016.03.003
with the French school of thought and most of the current literature. Conversely, the current article by Heckmann et al. defined the anterolateral ligament to attach at the lateral epicondyle as per the original work by Claes et al.8 However, agreement about the tibial attachment location of the anterolateral ligament is almost universal. Almost all of the literature, in spite of the disagreement about where the femoral attachment site is located, reports that the tibial attachment of the anterolateral ligament is located approximately midway between the Gerdy tubercle and the anterior margin of the fibular head. Thus, it brings us back to the anatomy. My concerns are that these authors have confirmed the radiographic landmarks for the femoral attachment site for the anterolateral ligament based on the original article by Claes et al.8 and their findings differ from the other 2 articles that were recently published on this topic.7,9 Ultimately, our goal needs to be to reach consensus on this topic so that we can ultimately improve the care of patients. Overall, it appears that the ideal location to define the correct location of the radiographic landmarks on lateral radiographs for the anterolateral ligament of the knee still needs to be defined by other groups. I believe that a major issue with the differing descriptions of the anatomic attachment locations, and ultimately the radiographic landmarks, lies in the fact that the anterolateral ligament is primarily a thickening of the lateral capsule and not a well-defined structure like others that are more clearly visible and can be readily agreed on by multiple teaching centers. Further study needs to be performed on fresh-frozen knees because the anterolateral ligament is a capsular thickening, which requires one to be able to palpate it while both flexing and extending the knee. Clearly, we all need to reach
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 32, No 5 (May), 2016: pp 849-850
849
850
EDITORIAL COMMENTARY
a consensus on the quantitative anatomic location of the anterolateral ligament before we can best determine the locations of the radiographic landmarks and, ultimately, anatomic-based reconstructions. Robert F. LaPrade, M.D., Ph.D. Vail, Colorado
5.
6.
References 1. Heckmann N, Sivasundaram L, Villacis D, et al. Radiographic landmarks for identifying the anterolateral ligament of the knee. Arthroscopy 2016;32:844-848. 2. Wijdicks CA, Griffith CJ, LaPrade RF, et al. Radiographic identification of primary medial knee structures. J Bone Joint Surg Am 2009;91:521-529. 3. Pietrini SD, LaPrade RF, Griffith CJ, Wijdicks CA, Ziegler CG. Radiographic identification of the primary posterolateral knee structures. Am J Sports Med 2009;37: 542-551. 4. James EW, LaPrade CM, Elman MB, Wijdicks CA, Engebretsen L, LaPrade RF. Radiographic identification of
7.
8.
9.
anterior and posterior root attachments of the medial and lateral menisci. Am J Sports Med 2014;42:2707-2714. Johannsen AM, Anderson CJ, Wijdicks CA, Engebretsen L, LaPrade RF. Radiographic landmarks for tunnel positioning in posterior cruciate ligament reconstructions. Am J Sports Med 2013;41:35-42. Pietrini SD, Ziegler CG, Anderson CJ, et al. Radiographic landmarks for tunnel positioning double-bundle ACL reconstructions. Knee Surg Sports Traumatol Arthrosc 2011;19:792-800. Kennedy MI, Claes S, Fuso FA, et al. The anterolateral ligament: An anatomic, radiographic, and biomechanical analysis. Am J Sports Med 2015;43:1606-1615. Claes S, Vereeche E, Maes M, Victor J, Verdonk P, Bellemans J. Anatomy of the anterolateral ligament of the knee. J Anat 2013;223:321-328. Rezansoff AJ, Caterine S, Spencer L, Tron MN, Litchfield RB, Getgood AM. Radiographic landmarks for surgical reconstruction of the anterolateral ligament of the knee. Knee Surg Sports Traumatol Arthrosc 2015;23: 3196-3201.
Abstract: Radiographic landmarks as defined by the original definition of the anterolateral ligament at the knee are provided.
See related article on page 844
T
he article by Heckmann et al.1 strives to further define the radiographic landmarks for identifying the anterolateral ligament of the knee. I believe that this type of study is useful because all of our previous works in this area around the knee2-6 have proved to be very helpful for the intraoperative identification of ligament attachment landmarks and also for the postoperative identification of reconstruction tunnels to determine if these structures have been anatomically repositioned. Overall, I believe that the methods for the study were performed well. The locations of the radiopaque markers were checked by a minimum of 4 authors, and the radiographic calibration of the distances was calculated. I have particularly found the issue of radiographic calibration to be very important because placing the calibration marker either on top or under the specimen in our hands was found to change the radiographic magnification distances by 10% or more. This brings us to the topic of the anatomy. We have recently worked on an anterolateral ligament anatomy publication7 with Steven Claes, whose original anatomy article on formalin-preserved knees8 was referenced for the landmarks that Heckmann et al.1 have noted for the positioning of their radiographic markers. In our study, which was performed on fresh-frozen knees, we found that the anterolateral ligament attaches posterior to the lateral epicondyle, with some specimens concurrently having some attachment fibers that coursed to the lateral epicondyle. The more posterior attachment site of the anterolateral ligament defined in our recent anatomy article7 generally fits
Ó 2016 by the Arthroscopy Association of North America 0749-8063/16207/$36.00 http://dx.doi.org/10.1016/j.arthro.2016.03.003
with the French school of thought and most of the current literature. Conversely, the current article by Heckmann et al. defined the anterolateral ligament to attach at the lateral epicondyle as per the original work by Claes et al.8 However, agreement about the tibial attachment location of the anterolateral ligament is almost universal. Almost all of the literature, in spite of the disagreement about where the femoral attachment site is located, reports that the tibial attachment of the anterolateral ligament is located approximately midway between the Gerdy tubercle and the anterior margin of the fibular head. Thus, it brings us back to the anatomy. My concerns are that these authors have confirmed the radiographic landmarks for the femoral attachment site for the anterolateral ligament based on the original article by Claes et al.8 and their findings differ from the other 2 articles that were recently published on this topic.7,9 Ultimately, our goal needs to be to reach consensus on this topic so that we can ultimately improve the care of patients. Overall, it appears that the ideal location to define the correct location of the radiographic landmarks on lateral radiographs for the anterolateral ligament of the knee still needs to be defined by other groups. I believe that a major issue with the differing descriptions of the anatomic attachment locations, and ultimately the radiographic landmarks, lies in the fact that the anterolateral ligament is primarily a thickening of the lateral capsule and not a well-defined structure like others that are more clearly visible and can be readily agreed on by multiple teaching centers. Further study needs to be performed on fresh-frozen knees because the anterolateral ligament is a capsular thickening, which requires one to be able to palpate it while both flexing and extending the knee. Clearly, we all need to reach
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 32, No 5 (May), 2016: pp 849-850
849
850
EDITORIAL COMMENTARY
a consensus on the quantitative anatomic location of the anterolateral ligament before we can best determine the locations of the radiographic landmarks and, ultimately, anatomic-based reconstructions. Robert F. LaPrade, M.D., Ph.D. Vail, Colorado
5.
6.
References 1. Heckmann N, Sivasundaram L, Villacis D, et al. Radiographic landmarks for identifying the anterolateral ligament of the knee. Arthroscopy 2016;32:844-848. 2. Wijdicks CA, Griffith CJ, LaPrade RF, et al. Radiographic identification of primary medial knee structures. J Bone Joint Surg Am 2009;91:521-529. 3. Pietrini SD, LaPrade RF, Griffith CJ, Wijdicks CA, Ziegler CG. Radiographic identification of the primary posterolateral knee structures. Am J Sports Med 2009;37: 542-551. 4. James EW, LaPrade CM, Elman MB, Wijdicks CA, Engebretsen L, LaPrade RF. Radiographic identification of
7.
8.
9.
anterior and posterior root attachments of the medial and lateral menisci. Am J Sports Med 2014;42:2707-2714. Johannsen AM, Anderson CJ, Wijdicks CA, Engebretsen L, LaPrade RF. Radiographic landmarks for tunnel positioning in posterior cruciate ligament reconstructions. Am J Sports Med 2013;41:35-42. Pietrini SD, Ziegler CG, Anderson CJ, et al. Radiographic landmarks for tunnel positioning double-bundle ACL reconstructions. Knee Surg Sports Traumatol Arthrosc 2011;19:792-800. Kennedy MI, Claes S, Fuso FA, et al. The anterolateral ligament: An anatomic, radiographic, and biomechanical analysis. Am J Sports Med 2015;43:1606-1615. Claes S, Vereeche E, Maes M, Victor J, Verdonk P, Bellemans J. Anatomy of the anterolateral ligament of the knee. J Anat 2013;223:321-328. Rezansoff AJ, Caterine S, Spencer L, Tron MN, Litchfield RB, Getgood AM. Radiographic landmarks for surgical reconstruction of the anterolateral ligament of the knee. Knee Surg Sports Traumatol Arthrosc 2015;23: 3196-3201.