Step-by-Step Arthroscopic Assessment of the Anterolateral Ligament of the Knee Using Anatomic Landmarks Assem “Mohamed Nour Eldin” Zein, M.D.
Abstract: New insights into the existence and function of the anterolateral ligament (ALL) of the knee have redirected and refocused attention on the secondary restraints of rotational stability of the knee. The importance of assessing the ALL is increasing, especially in anterior cruciate ligament reconstruction surgery, to decide on the need for an adjunctive extraarticular reconstruction of the ALL to control rotational instability of the knee. However, preoperative assessment of this ligament is difficult. Clinical assessment of rotatory instability has poor reproducibility. Moreover, it is difficult to assess by current imaging techniques. We describe an easy, simple, practical, safe, and reproducible arthroscopic technique to fully assess the ALL of the knee.
T
he anterolateral ligament (ALL) has recently been established as a distinct ligamentous structure found at the anterolateral (AL) aspect of the human knee. The ALL runs an oblique course with a consistent origin at the lateral femoral epicondyle and has a consistent strong connection at the periphery of the middle third of the body of the lateral meniscus (LM). The distal attachment of the ALL is divided into meniscofemoral and meniscotibial portions, above and under the meniscal rim, respectively. The meniscotibial attachment lies between the Gerdy tubercle and the head of the fibula.1-4 There is increased interest in the role of the ALL in controlling knee rotatory instability. This has aroused the subsequent need for extra-articular reconstructive procedures for injured ALLs, in conjunction with the standard intra-articular anterior cruciate ligament (ACL) reconstruction to control the pivot shift4-6 and prevent failure of the reconstructed ACL.7 Arthroscopic assessment of the ALL and lateral structures of the knee
From the Department of Orthopedic Surgery, Faculty of Medicine, Minia University, Minia, Egypt. The author reports that he has no conflicts of interest in the authorship and publication of this article. Received April 24, 2015; accepted August 4, 2015. Address correspondence to Assem “Mohamed Nour Eldin” Zein, M.D., Department of Orthopedic Surgery, Faculty of Medicine, Minia University, 39 Shalaby, Minia, Egypt. E-mail: [email protected] Ó 2016 by the Arthroscopy Association of North America 2212-6287/15378/$36.00 http://dx.doi.org/10.1016/j.eats.2015.08.002
could facilitate both diagnosis of rotational instability due to ALL injury and accurate, less invasive anatomic ALL reconstruction. The aim of our study was to describe, in a step-by-step manner, an easy, simple, practical, safe, and reproducible arthroscopic technique for identification and full examination of the ALL and lateral structures of the knee, using consistent anatomic descriptions of the lateral gutter structures (popliteus tendon [PT], lateral collateral ligament [LCL], and ALL) and arthroscopic landmarks that are described in this report.
Technique With the patient lying supine, a tourniquet is applied to the thigh. Standard knee arthroscopy is performed through a high AL portal with a 30 arthroscope (Hopkins II; Karl Storz, Tuttlingen, Germany). The lateral compartment is opened by a varus force applied by the surgeon’s thigh to the patient’s leg against the side of the table. The lateral compartment is examined with the limb in the “figure-of-4” position. The lateral border of the foot is placed on the opposite leg, and a varus force is applied to the distal thigh by an assistant. After inspecting the LM, the surgeon identifies the PT, which posteriorly passes in the popliteal hiatus, and the synovial bulge, which is present at the reattachment site of the capsule with the LM just anterior to the bare area of the LM. These 2 structures (with space between them) can be identified between the upper surface of the lateral border of the body of the
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Fig 1. Intraoperative photographs and arthroscopic images of a patient in the supine position with a tourniquet applied to the thigh of his left lower limb. (A) The surgeon applies a varus force (arrow) to the left lower leg to open the lateral compartment. The arthroscope is introduced in the lateral compartment through the high anterolateral portal (viewing portal). The arthroscopic view shows the opened lateral compartment of the left knee in the same patient. (B) The limb is positioned in the figure-of-4 position. The lateral border of the foot is placed on the opposite leg, and a varus force is applied to the distal thigh by an assistant. The arthroscope is introduced into the lateral gutter through the anterolateral portal (viewing portal). The arthroscopic view shows the anatomic landmarks between the lateral femoral condyle and the lateral border of the lateral meniscus. The synovial bulge is present anterior to the bare area of the LM and anterior to the popliteus tendon (PT), with space between them. (FC, lateral femoral condyle; LM, lateral meniscus; LTP, lateral tibial plateau.)
LM and the lower surface of the lateral femoral condyle (Fig 1). Then, the arthroscope is advanced toward the PT using guidance to reach the lateral gutter and passing over the synovial bulge. In the lateral gutter, the 3 lateral structures (PT, LCL, and ALL) lie in different planes and their fibers run in different directions; therefore they can be easily identified (Fig 2). The LCL lies in contact with the PT distally (i.e., near the LM) and is crossed by the PT from posterior to anterior. The LCL inserts into the lateral aspect of the lateral femoral condyle. The ALL lies in a more anterior and lateral plane. It inserts proximally into the lateral aspect of the lateral femoral condyle close to the PT, anterior to the LCL. The ALL inserts distally into the lateral aspect of the middle third of the LM at the synovial bulge (i.e., anterior to the bare area of the LM). The synovial bulge is a synovial sleeve around the meniscal attachment of the ALL. This attachment can be determined by the increased tension of its fibers by pulling on the bare
area of the LM (Fig 3, Video 1). The ALL tightens with tibial internal rotation, and this tightness can be seen and felt with a probe (Karl Storz) (Fig 4, Video 1). The 3 lateral structures can be probed through the standard anteromedial portal (Video 1). If needed, an accessory portal can be developed directly and under direct visualization on the ALL by using the transillumination method and a needle (Fig 5). The meniscotibial attachment of the ALL can be seen and probed under the LM after the LM is elevated with a probe (handmade probe) and the arthroscope is advanced under the LM. The meniscotibial attachment lies anterior to the PT and tightens with tibial internal rotation (Fig 6, Video 1).
Discussion Achieving successful knee rotational laxity control has been a matter of concern and is key to ensuring knee stability.8 This led to the development of isolated extra-articular reconstruction for ACL injuries,9-11 but
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Fig 2. Arrangement of the 3 lateral structuresdpopliteus tendon (PT), anterolateral ligament (ALL), and lateral collateral ligament (LCL)din the lateral gutter. (A-E) Arthroscopic views of the lateral gutter structures when viewed from inside. Panels A-D show the left knee, whereas panel E shows the right knee. The patient is supine; the arthroscope is introduced through a high anterolateral portal while the limb is in the figure-of-4 position. The 3 lateral structures lie in different planes, and their fibers run in different directions, so they can be identified from each other. (F) Diagram of an anterolateral view of the right knee showing the arrangement of the lateral knee structures. Panel F reprinted with permission.3 (FC, femoral condyle.)
the results have been unsatisfactory.12 Attention was then directed toward ACL reconstruction; the results thus far have been satisfactory and are improving,6
Fig 3. Arthroscopic view of the right knee from a high anterolateral portal. The patient is supine with the limb in the figure-of-4 position. Pulling with a probe on the bare area (arrow) of the lateral meniscus (LM) through the standard anteromedial portal can help to identify the anterolateral ligament (ALL). (FC, femoral condyle; PT, popliteus tendon.)
but more than 15% of cases still show a positive pivot shift.13-16 This led to the development of double-bundle ACL reconstruction,17 which has yielded inconsistent results.18 New insights into the existence and function of the ALL have redirected and refocused attention on the secondary restraints of rotational stability of the knee.1,2,19 Segond20 in 1879 was the first author to describe the ALL as a “pearly, resistant, fibrous band which invariably showed extreme amounts of tension during forced internal rotation of the knee.” Hughston et al.8 in 1976 described it as a mid-third capsular ligament playing a role in the so-called AL instability pattern of the knee. More recently, the ALL has been described as a distinct ligamentous structure at the AL aspect of the knee with a consistent origin and insertion sites.1,19 The ligamentous nature had been confirmed by histologic investigation.2 Several biomechanical studies have shown that the ALL is very important in controlling internal rotation of the tibia.4,21 In a recent kinematic study, Monaco et al.22 have shown a high correlation between the pivot-shift phenomenon and injury to the ALL. In addition, injuries to the lateral structures of the knee have been shown to produce a positive pivot-shift sign in knees with intact ACLs.4,21,23 George et al.7 noted that failure to recognize and treat concomitant injury to the ALL puts increased stress on the
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Fig 4. The intraoperative photograph shows a top view of a patient in the supine position with the right lower limb in the figure-of-4 position. The surgeon stands on the right side of the patient with the assistant applying a varus force to the distal thigh to open the lateral compartment. The arthroscope is introduced through a high anterolateral portal. Internal rotation of the tibia can be applied by another assistant or by the surgeon. The arthroscopic views show a lax anterolateral ligament (ALL) and a tightened ALL with internal rotation of the tibia in the same patient. (AM, anteromedial; FC, femoral condyle; LM, lateral meniscus; PT, popliteus tendon.)
reconstructed ACL and can be a cause of failure. Claes et al.,24 in a recent magnetic resonance imaging study of the ALL in knees with ACL injury, noted that most ALL injuries occur at the tibial attachment. Thus, increasing evidence is pointing toward the importance of full assessment of the ALL, especially in ACL reconstruction surgery to decide on the need for
adjunctive extra-articular reconstruction. Defining the ALL using conventional sonographic and magnetic resonance imaging is difficult, with few published data5; in addition, clinical assessment using the pivot-shift test, which is the most specific test to determine knee rotational instability,25 can be difficult because this test is based on the
Fig 5. (A) Intraoperative photograph of a patient in the supine position with a tourniquet applied to the thigh of his left lower limb. An assistant applies a varus force to the left lower thigh to open the lateral compartment. The arthroscope is introduced in the lateral gutter through a high anterolateral portal (viewing portal). A direct portal can be created under direct vision of the anterolateral ligament (ALL) by using an 18-gauge needle and transillumination. (B) Arthroscopic view of the same patient showing the needle used to properly locate the direct portal on the lateral gutter structures. (C) Arthroscopic view of the same patient showing assessment of the proximal part of the ALL through the direct portal. (FC, femoral condyle; LM, lateral meniscus; PT, popliteus tendon.)
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ANTEROLATERAL LIGAMENT OF KNEE
Fig 6. (A) Arthroscopic view of the left knee from the anterolateral portal. The patient is supine, and the limb is in the figure-of-4 position. A probe is used through the standard anteromedial portal to elevate the lateral meniscus (LM). (B) Arthroscopic view of the same patient showing the popliteus tendon (PT) in the popliteal hiatus under the lateral meniscus. The popliteus tendon serves as a landmark to identify the tibial attachment of the anterolateral ligament. (C) Arthroscopic view of the same patient with probing of the capsule and the reinforcing anterolateral ligament (star) anterior to the popliteus tendon, as well as inspection of the lateral recess. (D) Arthroscopic view of the same patient showing tightness of the capsule and reinforcing anterolateral ligament (ALL) with tibial internal rotation. (TP, tibial plateau.)
examiner’s subjective judgment of the tibial translation and rotation and is subject to interobserver variability.26,27 We describe a safe, simple, practical, and reproducible arthroscopic technique with a short learning curve to fully assess the ALL of the knee. To our knowledge, there is only 1 technique, described by Sonnery-Cottet et al.5 in 2014, by which to identify the ALL arthroscopically. However, this technique was performed in only 1 patient who underwent arthroscopic treatment for iliotibial band syndrome; the second part of their study was performed on a cadaver. Furthermore, in their study only the proximal part of the ALL could be identified after massive debridement of the synovial tissues in the lateral gutter by a shaver; this may cause injury to the ALL itself, besides the added risk of morbidity for the patient. Moreover, Sonnery-Cottet et al. were unable to assess the tibial part of the ALL. Our technique was proved to be reproducible because it was performed in a larger number of patients; therefore we were able to describe the arthroscopic landmarks that guided us to the ALL in a step-by-step manner. Furthermore, we could examine both the femoral and the distal (tibial and meniscal) attachments of the ALL without changing the limb position because the figure-of-4 position enabled us to fully assess the
ALL through the standard anteromedial portal. If necessary, we could have created a direct portal on the ALL through which the proximal part of the ALL could be assessed with little or no debridement of tissues to avoid increasing the risk of morbidity to the patient or injuring any surrounding structures. We used the high AL portal as a viewing portal in all cases because it is the most widely used portal in anatomic ACL reconstruction (Table 1). A limitation of this study is that there was no cadaveric study; this is because fresh cadavers were not available. However, the high number of cases yielded reproducible, consistent data, and our findings are consistent with those of previous cadaveric studies of the ALL, such as those by Claes et al.1 and Helito et al.,2 which described the triangle image formed by the meniscal insertion of the ALL, PT, and tibia when viewing the ALL from inside, as well as those by Vincent et al.3 and Dodds et al.19 (Fig 7). In conclusion, we present a safe, simple, practical, and reproducible arthroscopic technique with a short learning curve to fully assess the ALL of the knee.
Acknowledgment The author thanks Rania Ali Moharam for her support.
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Table 1. Surgical Steps, Pearls, and Pitfalls Surgical Steps Knee positioning in figure-of-4 position
Identification of PT
Debridement of soft tissues (e.g., synovium and fat) covering ALL Placement of standard AM portal
Placement of direct accessory portal
Identification of 3 lateral structures
Assessment of tibial attachment of capsule and ALL
Pearls
Pitfalls
The lateral compartment can be better visualized. The PT can be easily identified. The leg and foot are free from the table, so internal rotation of the tibia can be applied easily. The figure-of-4 position helps to advance the arthroscope under the LM easily, with better assessment of the undersurface of the LM, the PT, and the lateral capsule with its reinforcing ligaments. The PT is a fixed anatomic landmark and serves as a guide for the lateral structures in the lateral gutter, as well as a landmark for the tibial attachment of the ALL. Debridement is not needed in most cases. If needed, debridement is performed under direct vision of the ALL and is limited to the soft tissues impairing ALL visualization. Debridement is performed with a shaver or blunt instrument. An 18-gauge needle is used to properly place the AM portal.
The surgeon should use gentle rolling and gliding movements of the arthroscope while advancing into the lateral gutter or under the LM to avoid injuring the articular cartilage.
Use of transillumination and an 18-gauge needle help to properly place the direct portal. The direct portal is developed only if there is difficulty in assessing the ALL through the standard AM portal. Only the proximal part of the ALL can be assessed through the direct portal. The 3 lateral structures (PT, LCL, and ALL) lie in different planes and each runs in a different direction, so they can be identified from each other. Tibial internal rotation tightens the ALL and helps in its identification. Pulling on the bare area of the LM moves the ALL and helps in its identification. A probe is used to elevate the LM; then, advancing the arthroscope under the LM will maintain the LM in an elevated position. The surgeon should proceed gently toward the periphery of the undersurface of the LM by gentle gliding and rolling movements of the arthroscope. The capsular and ALL tibial attachments are located anterior to the PT and tighten with tibial internal rotation.
The PT may not be identified well in positions other than the figure-of-4 position. The ALL may be injured if debridement is performed blindly. Unnecessary extensive debridement of the soft tissues increases the risk of morbidity to the patient. Improper placement of the AM portal makes assessment of the lateral structures difficult, with the possibility of injuring the lateral femoral condyle by the instrumentation through this portal. Improper placement of the direct portal prevents proper assessment of the ALL and other lateral structures.
Injuring the cartilage of the tibial plateau will impair vision and increases the risk of morbidity to the patient.
ALL, anterolateral ligament; AM, anteromedial; LCL, lateral collateral ligament; LM, lateral meniscus; PT, popliteus tendon.
Fig 7. (A) Superior view of the tibial plateau of the left knee of a cadaveric specimen showing the course of the anterolateral ligament (asterisk) arising from the lateral femoral condyle (LFC) and inserting into the lateral meniscus (LM) and showing its relation with the popliteus tendon (Pop). The lateral tibial plateau (LTP) and medial tibial plateau (MTP) are also shown. Reprinted with permission.3 (B) Inside view of the lateral section of the right knee of a cadaveric specimen showing a triangular image with a distal base formed by the tibia, popliteus tendon (2), and meniscal portion of the anterolateral ligament (1). Reprinted with permission.2 (C) Arthroscopic view of the right knee viewed from a high anterolateral portal with the limb in the figure-of-4 position showing a triangular image with a distal base formed by the tibia, popliteus tendon (PT, 2), and meniscal portion of the anterolateral ligament (ALL, 1). (FC, lateral femoral condyle.)
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References 1. Claes S, Vereecke E, Maes M, et al. Anatomy of the anterolateral ligament of the knee. J Anat 2013;223:321-328. 2. Helito CP, Demange MK, Bonadio MB, et al. Anatomy and histology of the knee anterolateral ligament. Orthop J Sports Med 2013;1:1-5. 3. Vincent JP, Magnussen RA, Gezmez F, et al. The anterolateral ligament of the human knee: An anatomic and histologic study. Knee Surg Sports Traumatol Arthrosc 2012;20:147-152. 4. Parsons EM, Gee AO, Spiekerman C, Cavanagh PR. The biomechanical function of the anterolateral ligament of the knee. Am J Sports Med 2015;20:669-674. 5. Sonnery-Cottet B, Archbold P, Rezende FC, Neto AM, Fayard JM, Thaunat M. Arthroscopic identification of the anterolateral ligament of the knee. Arthrosc Tech 2014;3: e389-e392. 6. Sonnery-Cottet B, Thaunat M, Freychet B, Pupim BH, Murphy CG, Claes S. Outcome of a combined anterior cruciate ligament and anterolateral ligament reconstruction technique with a minimum 2-year follow-up. Am J Sports Med 2015;43:1598-1605. 7. George MS, Dunn WR, Spindler KP. Current concepts review: Revision anterior cruciate ligament reconstruction. Am J Sports Med 2006;34:2026-2037. 8. Hughston JC, Andrews JR, Cross MJ, Moschi A. Classification of knee ligament instabilities, part II: The lateral compartment. J Bone Joint Surg Am 1976;58:173-179. 9. Ireland J, Trickey EL. Macintosh tenodesis for anterolateral instability of the knee. J Bone Joint Surg Br 1980;62: 340-345. 10. Losee RE, Johnson TR, Southwick WO. Anterior subluxation of the lateral tibial plateau: A diagnostic test and operative repair. J Bone Joint Surg Am 1978;60: 1015-1030. 11. Ellison AE. Distal iliotibial-band transfer for anterolateral rotator instability of the knee. J Bone Joint Surg Am 1979;61:330-337. 12. Dodds AL, Gupte CM, Neyret P, et al. Extra-articular techniques in anterior cruciate ligament reconstruction: A literature review. J Bone Joint Surg Br 2011;93:1440-1448. 13. Bach BR, Tradonski S, Bojchuk J, et al. Arthroscopically assisted anterior cruciate ligament reconstruction using patellar tendon autografts: Five- to nine-year follow-up evaluation. Am J Sports Med 1998;26:20-29. 14. Biau DJ, Tournoux C, Katsahian S, et al. ACL reconstruction: A meta-analysis of functional scores. Clin Orthop Relat Res 2007;458:180-187.
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15. Gillquist J, Messner K. Anterior cruciate ligament reconstruction and the long-term incidence of gonarthrosis. Sports Med 1999;27:143-156. 16. Chouliaras V, Ristanis S, Moraiti C, Stergiou N, Georgoulis AD. Effectiveness of reconstruction of the anterior cruciate ligament with quadrupled hamstrings and bone-patellar tendon-bone autografts: An in vivo study comparing tibial internal-external rotation. Am J Sports Med 2007;35:189-196. 17. Yasuda K, Kondo E, Ichiyama H, et al. Anatomic reconstruction of the anteromedial and posterolateral bundles of the anterior cruciate ligament using hamstring tendon grafts. Arthroscopy 2004;20:1015-1025. 18. Meredick RB, Vance KJ, Appleby D, Lubowitz JH. Outcome of single-bundle versus double-bundle reconstruction of the anterior cruciate ligament: A meta-analysis. Am J Sports Med 2008;36:1414-1421. 19. Dodds AL, Halewood C, Gupte CM, Williams A, Amis AA. The anterolateral ligament: Anatomy, length changes and association with the Segond fracture. Bone Joint J 2014;96: 325-331. 20. Segond P. Recherches cliniques et expérimentales sur les épanchements sanguins du genou par entorse. Progrés Med 1879;7:297-341 [in French]. 21. Norwood LA, Andrews JR, Meisterling RC, Glancy GL. Acute anterolateral rotatory instability of the knee. J Bone Joint Surg Am 1979;61:704-709. 22. Monaco E, Maestri B, Labianca L, et al. Navigated knee kinematics after tear of the ACL and its secondary restraints: Preliminary results. Orthopedics 2010;33:87-93 (suppl). 23. Tanaka M, Vyas D, Moloney G, et al. What does it take to have a high-grade pivot shift? Knee Surg Sports Traumatol Arthrosc 2012;20:737-742. 24. Claes S, Bartholomeeusen S, Bellemans J. High prevalence of anterolateral ligament abnormalities in magnetic resonance images of anterior cruciate ligament-injured knees. Acta Orthop Belg 2014;80:45-49. 25. Galway R, Beaupré A, MacIntosh DL. A clinical sign of symptomatic cruciate insufficiency. J Bone Joint Surg Br 1973;54:763-764. 26. Lane CG, Warren R, Pearle AD. The pivot shift. J Am Acad Orthop Surg 2008;16:679-688. 27. Kocher MS, Steadman JR, Briggs KK, et al. Relationships between objective assessment of ligament stability and subjective assessment of symptoms and function after anterior cruciate ligament reconstruction. Am J Sports Med 2004;32:629-634.
Abstract: New insights into the existence and function of the anterolateral ligament (ALL) of the knee have redirected and refocused attention on the secondary restraints of rotational stability of the knee. The importance of assessing the ALL is increasing, especially in anterior cruciate ligament reconstruction surgery, to decide on the need for an adjunctive extraarticular reconstruction of the ALL to control rotational instability of the knee. However, preoperative assessment of this ligament is difficult. Clinical assessment of rotatory instability has poor reproducibility. Moreover, it is difficult to assess by current imaging techniques. We describe an easy, simple, practical, safe, and reproducible arthroscopic technique to fully assess the ALL of the knee.
T
he anterolateral ligament (ALL) has recently been established as a distinct ligamentous structure found at the anterolateral (AL) aspect of the human knee. The ALL runs an oblique course with a consistent origin at the lateral femoral epicondyle and has a consistent strong connection at the periphery of the middle third of the body of the lateral meniscus (LM). The distal attachment of the ALL is divided into meniscofemoral and meniscotibial portions, above and under the meniscal rim, respectively. The meniscotibial attachment lies between the Gerdy tubercle and the head of the fibula.1-4 There is increased interest in the role of the ALL in controlling knee rotatory instability. This has aroused the subsequent need for extra-articular reconstructive procedures for injured ALLs, in conjunction with the standard intra-articular anterior cruciate ligament (ACL) reconstruction to control the pivot shift4-6 and prevent failure of the reconstructed ACL.7 Arthroscopic assessment of the ALL and lateral structures of the knee
From the Department of Orthopedic Surgery, Faculty of Medicine, Minia University, Minia, Egypt. The author reports that he has no conflicts of interest in the authorship and publication of this article. Received April 24, 2015; accepted August 4, 2015. Address correspondence to Assem “Mohamed Nour Eldin” Zein, M.D., Department of Orthopedic Surgery, Faculty of Medicine, Minia University, 39 Shalaby, Minia, Egypt. E-mail: [email protected] Ó 2016 by the Arthroscopy Association of North America 2212-6287/15378/$36.00 http://dx.doi.org/10.1016/j.eats.2015.08.002
could facilitate both diagnosis of rotational instability due to ALL injury and accurate, less invasive anatomic ALL reconstruction. The aim of our study was to describe, in a step-by-step manner, an easy, simple, practical, safe, and reproducible arthroscopic technique for identification and full examination of the ALL and lateral structures of the knee, using consistent anatomic descriptions of the lateral gutter structures (popliteus tendon [PT], lateral collateral ligament [LCL], and ALL) and arthroscopic landmarks that are described in this report.
Technique With the patient lying supine, a tourniquet is applied to the thigh. Standard knee arthroscopy is performed through a high AL portal with a 30 arthroscope (Hopkins II; Karl Storz, Tuttlingen, Germany). The lateral compartment is opened by a varus force applied by the surgeon’s thigh to the patient’s leg against the side of the table. The lateral compartment is examined with the limb in the “figure-of-4” position. The lateral border of the foot is placed on the opposite leg, and a varus force is applied to the distal thigh by an assistant. After inspecting the LM, the surgeon identifies the PT, which posteriorly passes in the popliteal hiatus, and the synovial bulge, which is present at the reattachment site of the capsule with the LM just anterior to the bare area of the LM. These 2 structures (with space between them) can be identified between the upper surface of the lateral border of the body of the
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Fig 1. Intraoperative photographs and arthroscopic images of a patient in the supine position with a tourniquet applied to the thigh of his left lower limb. (A) The surgeon applies a varus force (arrow) to the left lower leg to open the lateral compartment. The arthroscope is introduced in the lateral compartment through the high anterolateral portal (viewing portal). The arthroscopic view shows the opened lateral compartment of the left knee in the same patient. (B) The limb is positioned in the figure-of-4 position. The lateral border of the foot is placed on the opposite leg, and a varus force is applied to the distal thigh by an assistant. The arthroscope is introduced into the lateral gutter through the anterolateral portal (viewing portal). The arthroscopic view shows the anatomic landmarks between the lateral femoral condyle and the lateral border of the lateral meniscus. The synovial bulge is present anterior to the bare area of the LM and anterior to the popliteus tendon (PT), with space between them. (FC, lateral femoral condyle; LM, lateral meniscus; LTP, lateral tibial plateau.)
LM and the lower surface of the lateral femoral condyle (Fig 1). Then, the arthroscope is advanced toward the PT using guidance to reach the lateral gutter and passing over the synovial bulge. In the lateral gutter, the 3 lateral structures (PT, LCL, and ALL) lie in different planes and their fibers run in different directions; therefore they can be easily identified (Fig 2). The LCL lies in contact with the PT distally (i.e., near the LM) and is crossed by the PT from posterior to anterior. The LCL inserts into the lateral aspect of the lateral femoral condyle. The ALL lies in a more anterior and lateral plane. It inserts proximally into the lateral aspect of the lateral femoral condyle close to the PT, anterior to the LCL. The ALL inserts distally into the lateral aspect of the middle third of the LM at the synovial bulge (i.e., anterior to the bare area of the LM). The synovial bulge is a synovial sleeve around the meniscal attachment of the ALL. This attachment can be determined by the increased tension of its fibers by pulling on the bare
area of the LM (Fig 3, Video 1). The ALL tightens with tibial internal rotation, and this tightness can be seen and felt with a probe (Karl Storz) (Fig 4, Video 1). The 3 lateral structures can be probed through the standard anteromedial portal (Video 1). If needed, an accessory portal can be developed directly and under direct visualization on the ALL by using the transillumination method and a needle (Fig 5). The meniscotibial attachment of the ALL can be seen and probed under the LM after the LM is elevated with a probe (handmade probe) and the arthroscope is advanced under the LM. The meniscotibial attachment lies anterior to the PT and tightens with tibial internal rotation (Fig 6, Video 1).
Discussion Achieving successful knee rotational laxity control has been a matter of concern and is key to ensuring knee stability.8 This led to the development of isolated extra-articular reconstruction for ACL injuries,9-11 but
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Fig 2. Arrangement of the 3 lateral structuresdpopliteus tendon (PT), anterolateral ligament (ALL), and lateral collateral ligament (LCL)din the lateral gutter. (A-E) Arthroscopic views of the lateral gutter structures when viewed from inside. Panels A-D show the left knee, whereas panel E shows the right knee. The patient is supine; the arthroscope is introduced through a high anterolateral portal while the limb is in the figure-of-4 position. The 3 lateral structures lie in different planes, and their fibers run in different directions, so they can be identified from each other. (F) Diagram of an anterolateral view of the right knee showing the arrangement of the lateral knee structures. Panel F reprinted with permission.3 (FC, femoral condyle.)
the results have been unsatisfactory.12 Attention was then directed toward ACL reconstruction; the results thus far have been satisfactory and are improving,6
Fig 3. Arthroscopic view of the right knee from a high anterolateral portal. The patient is supine with the limb in the figure-of-4 position. Pulling with a probe on the bare area (arrow) of the lateral meniscus (LM) through the standard anteromedial portal can help to identify the anterolateral ligament (ALL). (FC, femoral condyle; PT, popliteus tendon.)
but more than 15% of cases still show a positive pivot shift.13-16 This led to the development of double-bundle ACL reconstruction,17 which has yielded inconsistent results.18 New insights into the existence and function of the ALL have redirected and refocused attention on the secondary restraints of rotational stability of the knee.1,2,19 Segond20 in 1879 was the first author to describe the ALL as a “pearly, resistant, fibrous band which invariably showed extreme amounts of tension during forced internal rotation of the knee.” Hughston et al.8 in 1976 described it as a mid-third capsular ligament playing a role in the so-called AL instability pattern of the knee. More recently, the ALL has been described as a distinct ligamentous structure at the AL aspect of the knee with a consistent origin and insertion sites.1,19 The ligamentous nature had been confirmed by histologic investigation.2 Several biomechanical studies have shown that the ALL is very important in controlling internal rotation of the tibia.4,21 In a recent kinematic study, Monaco et al.22 have shown a high correlation between the pivot-shift phenomenon and injury to the ALL. In addition, injuries to the lateral structures of the knee have been shown to produce a positive pivot-shift sign in knees with intact ACLs.4,21,23 George et al.7 noted that failure to recognize and treat concomitant injury to the ALL puts increased stress on the
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Fig 4. The intraoperative photograph shows a top view of a patient in the supine position with the right lower limb in the figure-of-4 position. The surgeon stands on the right side of the patient with the assistant applying a varus force to the distal thigh to open the lateral compartment. The arthroscope is introduced through a high anterolateral portal. Internal rotation of the tibia can be applied by another assistant or by the surgeon. The arthroscopic views show a lax anterolateral ligament (ALL) and a tightened ALL with internal rotation of the tibia in the same patient. (AM, anteromedial; FC, femoral condyle; LM, lateral meniscus; PT, popliteus tendon.)
reconstructed ACL and can be a cause of failure. Claes et al.,24 in a recent magnetic resonance imaging study of the ALL in knees with ACL injury, noted that most ALL injuries occur at the tibial attachment. Thus, increasing evidence is pointing toward the importance of full assessment of the ALL, especially in ACL reconstruction surgery to decide on the need for
adjunctive extra-articular reconstruction. Defining the ALL using conventional sonographic and magnetic resonance imaging is difficult, with few published data5; in addition, clinical assessment using the pivot-shift test, which is the most specific test to determine knee rotational instability,25 can be difficult because this test is based on the
Fig 5. (A) Intraoperative photograph of a patient in the supine position with a tourniquet applied to the thigh of his left lower limb. An assistant applies a varus force to the left lower thigh to open the lateral compartment. The arthroscope is introduced in the lateral gutter through a high anterolateral portal (viewing portal). A direct portal can be created under direct vision of the anterolateral ligament (ALL) by using an 18-gauge needle and transillumination. (B) Arthroscopic view of the same patient showing the needle used to properly locate the direct portal on the lateral gutter structures. (C) Arthroscopic view of the same patient showing assessment of the proximal part of the ALL through the direct portal. (FC, femoral condyle; LM, lateral meniscus; PT, popliteus tendon.)
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ANTEROLATERAL LIGAMENT OF KNEE
Fig 6. (A) Arthroscopic view of the left knee from the anterolateral portal. The patient is supine, and the limb is in the figure-of-4 position. A probe is used through the standard anteromedial portal to elevate the lateral meniscus (LM). (B) Arthroscopic view of the same patient showing the popliteus tendon (PT) in the popliteal hiatus under the lateral meniscus. The popliteus tendon serves as a landmark to identify the tibial attachment of the anterolateral ligament. (C) Arthroscopic view of the same patient with probing of the capsule and the reinforcing anterolateral ligament (star) anterior to the popliteus tendon, as well as inspection of the lateral recess. (D) Arthroscopic view of the same patient showing tightness of the capsule and reinforcing anterolateral ligament (ALL) with tibial internal rotation. (TP, tibial plateau.)
examiner’s subjective judgment of the tibial translation and rotation and is subject to interobserver variability.26,27 We describe a safe, simple, practical, and reproducible arthroscopic technique with a short learning curve to fully assess the ALL of the knee. To our knowledge, there is only 1 technique, described by Sonnery-Cottet et al.5 in 2014, by which to identify the ALL arthroscopically. However, this technique was performed in only 1 patient who underwent arthroscopic treatment for iliotibial band syndrome; the second part of their study was performed on a cadaver. Furthermore, in their study only the proximal part of the ALL could be identified after massive debridement of the synovial tissues in the lateral gutter by a shaver; this may cause injury to the ALL itself, besides the added risk of morbidity for the patient. Moreover, Sonnery-Cottet et al. were unable to assess the tibial part of the ALL. Our technique was proved to be reproducible because it was performed in a larger number of patients; therefore we were able to describe the arthroscopic landmarks that guided us to the ALL in a step-by-step manner. Furthermore, we could examine both the femoral and the distal (tibial and meniscal) attachments of the ALL without changing the limb position because the figure-of-4 position enabled us to fully assess the
ALL through the standard anteromedial portal. If necessary, we could have created a direct portal on the ALL through which the proximal part of the ALL could be assessed with little or no debridement of tissues to avoid increasing the risk of morbidity to the patient or injuring any surrounding structures. We used the high AL portal as a viewing portal in all cases because it is the most widely used portal in anatomic ACL reconstruction (Table 1). A limitation of this study is that there was no cadaveric study; this is because fresh cadavers were not available. However, the high number of cases yielded reproducible, consistent data, and our findings are consistent with those of previous cadaveric studies of the ALL, such as those by Claes et al.1 and Helito et al.,2 which described the triangle image formed by the meniscal insertion of the ALL, PT, and tibia when viewing the ALL from inside, as well as those by Vincent et al.3 and Dodds et al.19 (Fig 7). In conclusion, we present a safe, simple, practical, and reproducible arthroscopic technique with a short learning curve to fully assess the ALL of the knee.
Acknowledgment The author thanks Rania Ali Moharam for her support.
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Table 1. Surgical Steps, Pearls, and Pitfalls Surgical Steps Knee positioning in figure-of-4 position
Identification of PT
Debridement of soft tissues (e.g., synovium and fat) covering ALL Placement of standard AM portal
Placement of direct accessory portal
Identification of 3 lateral structures
Assessment of tibial attachment of capsule and ALL
Pearls
Pitfalls
The lateral compartment can be better visualized. The PT can be easily identified. The leg and foot are free from the table, so internal rotation of the tibia can be applied easily. The figure-of-4 position helps to advance the arthroscope under the LM easily, with better assessment of the undersurface of the LM, the PT, and the lateral capsule with its reinforcing ligaments. The PT is a fixed anatomic landmark and serves as a guide for the lateral structures in the lateral gutter, as well as a landmark for the tibial attachment of the ALL. Debridement is not needed in most cases. If needed, debridement is performed under direct vision of the ALL and is limited to the soft tissues impairing ALL visualization. Debridement is performed with a shaver or blunt instrument. An 18-gauge needle is used to properly place the AM portal.
The surgeon should use gentle rolling and gliding movements of the arthroscope while advancing into the lateral gutter or under the LM to avoid injuring the articular cartilage.
Use of transillumination and an 18-gauge needle help to properly place the direct portal. The direct portal is developed only if there is difficulty in assessing the ALL through the standard AM portal. Only the proximal part of the ALL can be assessed through the direct portal. The 3 lateral structures (PT, LCL, and ALL) lie in different planes and each runs in a different direction, so they can be identified from each other. Tibial internal rotation tightens the ALL and helps in its identification. Pulling on the bare area of the LM moves the ALL and helps in its identification. A probe is used to elevate the LM; then, advancing the arthroscope under the LM will maintain the LM in an elevated position. The surgeon should proceed gently toward the periphery of the undersurface of the LM by gentle gliding and rolling movements of the arthroscope. The capsular and ALL tibial attachments are located anterior to the PT and tighten with tibial internal rotation.
The PT may not be identified well in positions other than the figure-of-4 position. The ALL may be injured if debridement is performed blindly. Unnecessary extensive debridement of the soft tissues increases the risk of morbidity to the patient. Improper placement of the AM portal makes assessment of the lateral structures difficult, with the possibility of injuring the lateral femoral condyle by the instrumentation through this portal. Improper placement of the direct portal prevents proper assessment of the ALL and other lateral structures.
Injuring the cartilage of the tibial plateau will impair vision and increases the risk of morbidity to the patient.
ALL, anterolateral ligament; AM, anteromedial; LCL, lateral collateral ligament; LM, lateral meniscus; PT, popliteus tendon.
Fig 7. (A) Superior view of the tibial plateau of the left knee of a cadaveric specimen showing the course of the anterolateral ligament (asterisk) arising from the lateral femoral condyle (LFC) and inserting into the lateral meniscus (LM) and showing its relation with the popliteus tendon (Pop). The lateral tibial plateau (LTP) and medial tibial plateau (MTP) are also shown. Reprinted with permission.3 (B) Inside view of the lateral section of the right knee of a cadaveric specimen showing a triangular image with a distal base formed by the tibia, popliteus tendon (2), and meniscal portion of the anterolateral ligament (1). Reprinted with permission.2 (C) Arthroscopic view of the right knee viewed from a high anterolateral portal with the limb in the figure-of-4 position showing a triangular image with a distal base formed by the tibia, popliteus tendon (PT, 2), and meniscal portion of the anterolateral ligament (ALL, 1). (FC, lateral femoral condyle.)
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