Anterior Cruciate Ligament Reconstruction With Preservation of Femoral Anterior Cruciate Ligament Stump Hira Lal Nag, M.S.Orth., and Himanshu Gupta, M.S.Orth.
Abstract: Anterior cruciate ligament (ACL) reconstruction with preservation of either the remnant or the tibial stump is performed with the hope of improving the vascularization and proprioceptive function of the graft. Remnant preservation is technically difficult because it hinders the visualization of the intra-articular tunnel site. Taking a cue from the concept of tibial stump preservation, we have modified our ACL reconstruction technique to preserve a sleeve of the soft tissue and ACL stump attached to the femoral condyle, in addition to tibial stump preservation, while still allowing adequate visualization of the femoral ACL insertion site. We describe our modification in this article and hypothesize that this should further improve graft vascularization and ligamentization.
A
nterior cruciate ligament (ACL) reconstruction with preservation of the remnant is performed with the hope of improving the vascularization and proprioceptive function of the graft.1-4 Remnant preservation is technically difficult because it hinders the visualization of the intra-articular tunnel site and tip of the guide pin.1 When the remnant is not attached to the femoral ACL footprint, the tibial stump may be preserved.1 Taking a cue from the concept of tibial stump preservation, we have modified our ACL reconstruction technique and we also preserve the ACL stump and soft tissue attached to the femoral condyle, in addition to tibial stump preservation. However, it is difficult to accurately position the tunnel or socket on the femoral side by an inside-out technique unless the soft tissue and ACL stump overlying the medial surface of the lateral femoral condyle are removed using a shaver or radiofrequency probe to completely expose the ACL footprint site. To solve this difficulty, we use a method to preserve this ACL stump attached to the femoral
From the Department of Orthopaedics, All India Institute of Medical Sciences (H.L.N., H.G.), New Delhi, India; and the Department of Orthopaedics, Glasgow Royal Infirmary (H.G.), Glasgow, Scotland. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received March 17, 2014; accepted June 17, 2014. Address correspondence to H. L. Nag, M.S.Orth., Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, 110029, India. E-mail: [email protected] Ó 2014 by the Arthroscopy Association of North America 2212-6287/14222/$36.00 http://dx.doi.org/10.1016/j.eats.2014.06.012
condyle in such a way that it still allows adequate visualization of the femoral ACL insertion site. This step can be added to one’s preferred technique of ACL reconstruction using any fixation method and graft type.
Technique
The patient is placed supine with the hip flexed at about 50 and knee flexed at about 100 . The portals (far anteromedial and anterolateral) are prepared in the usual way. With the arthroscope inserted through the anterolateral portal, a diagnostic arthroscopy is performed. The tibial ACL stump is assessed, and extra tissue is removed with an arthroscopic shaver or punch to leave a short stump of ACL tissue at the ACL footprint on the tibia (Video 1). If the remnant of the ACL is attached to the posterior cruciate ligament (PCL) surface or if there is fibrosis in the region between the PCL and the lateral femoral condyle, it is removed with a shaver inserted through the far anteromedial portal until the PCL is exposed. However, the ACL stump and soft tissue attached to the medial wall of the lateral femoral condyle are not removed. Instead, this tissue is elevated gently as a flap. To achieve this, with the knee kept at 100 of flexion, an arthroscopic liberator knife (ConMed Linvatec, Largo, FL) is inserted through the far anteromedial portal, and beginning from the resident’s ridge, the tissues are lifted off the bone of the medial wall of the lateral condyle (in the same way in which one would elevate the periosteum off the surface of a bone). This needs to be performed very gently and patiently, with the surgeon making sure that the tissues do not become fragmented. Working backward, this
Arthroscopy Techniques, Vol 3, No 5 (October), 2014: pp e575-e577
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soft tissue “flap” is lifted all the way to the osteochondral junction at the back until the bone is completely exposed at the ACL attachment site on the femoral condyle (Fig 1). This sheet of soft tissue, which is elevated, is left attached at the back. Through the far anteromedial portal, a medial transportal femoral offset guide (Arthrex, Naples, FL) of appropriate size is inserted and placed on the femoral ACL footprint site, keeping the elevated flap behind the offset guide. A femoral guide pin is inserted through the offset guide and drilled into the femur. The femoral socket (or tunnel, depending on the method of fixation chosen by the surgeon) is prepared over the pin in an inside-out manner. The surgeon needs to make sure that the soft-tissue flap does not become entangled with the guide pin or the drill (Fig 2). The tibial tunnel is prepared next, and graft passage and fixation are performed using standard methods. Before insertion of the graft, the soft-tissue flap is gently held with a tissue grasper to check that the flap is intact and to straighten it out. This helps in the smooth passage of the graft into the femoral tunnel or socket under direct arthroscopic vision; otherwise, the soft tissue, which has been harvested so carefully and patiently, will be caught and dragged along with the graft into the tunnel or socket, defeating the whole purpose. After reconstruction of the ligament, the soft-tissue flap, which is still attached at the back of the osteochondral junction, falls back over the posterosuperior aspect of the proximal part of the graft, and it is hypothesized that it should help in vascularization of the graft.
Fig 1. The left knee is being operated on, and the patient is lying supine with the hip flexed at about 50 and knee flexed at about 100 . The viewing portal is the anterolateral portal. The ACL stump is being elevated from the femoral condyle as a soft-tissue sheet using a tissue liberator.
Fig 2. The femoral socket has been prepared (with the same positioning as used in Fig 1). The soft-tissue sleeve is held with a tissue grasper to show how it will fall back over the posterosuperior aspect of the reconstructed ACL.
Discussion We describe a modification of standard ACL reconstruction methods involving preservation of the femoral-side ACL stump. Many clinical studies have shown potential benefit of remnant preservation in ACL reconstruction. This has been summed up by 2 recently published reviews, although both of them concluded that the current level of evidence is not strong enough to conclusively prove the superiority or advantage of remnant-preserving reconstruction techniques as compared with conventional techniques.3,4 When a continuous ACL remnant is available, its preservation has been shown to improve vascularization of the ACL graft, blood flow, ligamentization, tendon-to-bone integration, and proprioceptive function.3-6 Such improvement has also been suggested with even tibial stump preservation in cases in which there is no continuous remnant between the femur and tibia.1,2,7,8 Morphologically normal mechanoreceptors have been shown to be present in both tibial and femoral ACL stumps biopsied during ACL reconstructions.9,10 Preservation of a 2-mm ACL stump on the tibial side in a rabbit model has been shown to increase the number of vessels, as well as blood flow, in the ACL graft.7,8 The same authors also showed increased ligamentization, remodeling, tendon-to-bone integration, and biomechanical strength of the graft in a rabbit model with tibial stump preservation compared with that with complete removal of the ACL stump by cauterization.7,8 On the basis of all these reports, we hypothesize that the preservation of the femoral ACL stump that we have described should further improve graft vascularization and ligamentization.
e577
PRESERVATION OF FEMORAL ACL STUMP
There is some confusion in the literature in terms of terminology between a remnant and a stump. The term “ACL remnant” has been used to signify both a continuous strand of tissue between the tibia and the notch (or the PCL) even with a complete ACL deficiency,1,11 as well as the stump of the ACL tissue left at the tibial (or femoral) attachment site.2,7,8,12 These 2 concepts need to be clearly differentiated in the literature to aid in summarizing the results of different studies. We suggest that the term “remnant” may be used for the former (a continuous strand) and the term “stump” may be used for the latter to avoid confusion. Attempts to preserve the femoral ACL stump may compromise exposure for accurate positioning of the femoral socket and make the operation more challenging.3,13 In our technique, we elevate the available thin layer of tissue including the remnant of the ACL with gentle dissection over the femoral condyle, leaving it attached at the back, and then the tunnel or socket is made directly on the bone and not through the soft tissues. On the other hand, on the tibial side, the tunnel is made through the ACL remnant itself. In this way, one can understand the technical difficulty in preserving the soft-tissue flap until the passage and final fixation of the graft. Our method of preserving the ACL stump on the femoral side does not compromise visualization. Another potential concern with preserving the femoral ACL stump is impingement between the graft and the notch.3 Gohil et al.13 reported a 59% incidence of cyclops formation after ACL reconstruction with minimal debridement of the notch tissue compared with 37.5% in patients with standard debridement (although the difference did not reach statistical significance). However, the flap of soft tissue that we have described lies posterosuperior to the proximal part of the graft; thus it cannot cause any impingement. We could confirm this in our patients at the completion of surgery by visualizing the notch through the anterolateral portal while the knee was moved through a complete range of motion. Most ACL reconstructions are carried out after a period of gap after the initial injury, at which time the quality of this soft tissue overlying the medial wall of the lateral femoral condyle is thin and tends to become fragmented or detached easily. The look of the femoral condyle is deceptive at times in the sense that one may think that there is no soft tissue left for lifting as a flap. However, from our experience with this method, as one starts lifting the stump patiently, it is encouraging to continue it further. Initially, one may find it difficult to create the flap of soft tissues, but we have found that it becomes easy with practice. Furthermore, even if one does not find it happening, there is no harm to the patient because these remnant soft tissues at the
site are removed either with a shaver or thermal cautery.
References 1. Ochi M, Abouheif MM, Kongcharoensombat W, Nakamae A, Adachi N, Deie M. Double bundle arthroscopic anterior cruciate ligament reconstruction with remnant preserving technique using a hamstring autograft. Sports Med Arthrosc Rehabil Ther Technol 2011;3:30. 2. Lee B-I, Kwon S-W, Kim J-B, Choi H-S, Min K-D. Comparison of clinical results according to amount of preserved remnant in arthroscopic anterior cruciate ligament reconstruction using quadrupled hamstring graft. Arthroscopy 2008;24:560-568. 3. Papalia R, Franceschi F, Vasta S, Di Martino A, Maffulli N, Denaro V. Sparing the anterior cruciate ligament remnant: Is it worth the hassle? Br Med Bull 2012;104: 91-111. 4. Song G-Y, Zhang H, Zhang J, et al. The anterior cruciate ligament remnant: To leave it or not? Arthroscopy 2013;29: 1253-1262. 5. Adachi N, Ochi M, Uchio Y, Sumen Y. Anterior cruciate ligament augmentation under arthroscopy. A minimum 2-year follow-up in 40 patients. Arch Orthop Trauma Surg 2000;120:128-133. 6. Löcherbach C, Zayni R, Chambat P, Sonnery-Cottet B. Biologically enhanced ACL reconstruction. Orthop Traumatol Surg Res 2010;96:810-815. 7. Wu B, Zhao Z, Li S, Sun L. Preservation of remnant attachment improves graft healing in a rabbit model of anterior cruciate ligament reconstruction. Arthroscopy 2013;29:1362-1371. 8. Sun L, Wu B, Tian M, Liu B, Luo Y. Comparison of graft healing in anterior cruciate ligament reconstruction with and without a preserved remnant in rabbits. Knee 2013;20:537-544. 9. Dhillon MS, Bali K, Vasistha RK. Immunohistological evaluation of proprioceptive potential of the residual stump of injured anterior cruciate ligaments (ACL). Int Orthop 2010;34:737-741. 10. Bali K, Dhillon MS, Vasistha RK, Kakkar N, Chana R, Prabhakar S. Efficacy of immunohistological methods in detecting functionally viable mechanoreceptors in the remnant stumps of injured anterior cruciate ligaments and its clinical importance. Knee Surg Sports Traumatol Arthrosc 2012;20:75-80. 11. Nakamae A, Ochi M, Deie M, et al. Biomechanical function of anterior cruciate ligament remnants: How long do they contribute to knee stability after injury in patients with complete tears? Arthroscopy 2010;26:1577-1585. 12. Lee B-I, Min K-D, Choi H-S, Kim J-B, Kim S-T. Arthroscopic anterior cruciate ligament reconstruction with the tibial-remnant preserving technique using a hamstring graft. Arthroscopy 2006;22:340.e1-340.e7. 13. Gohil S, Annear PO, Breidahl W. Anterior cruciate ligament reconstruction using autologous double hamstrings: A comparison of standard versus minimal debridement techniques using MRI to assess revascularisation. A randomised prospective study with a one-year follow-up. J Bone Joint Surg Br 2007;89:1165-1171.
Abstract: Anterior cruciate ligament (ACL) reconstruction with preservation of either the remnant or the tibial stump is performed with the hope of improving the vascularization and proprioceptive function of the graft. Remnant preservation is technically difficult because it hinders the visualization of the intra-articular tunnel site. Taking a cue from the concept of tibial stump preservation, we have modified our ACL reconstruction technique to preserve a sleeve of the soft tissue and ACL stump attached to the femoral condyle, in addition to tibial stump preservation, while still allowing adequate visualization of the femoral ACL insertion site. We describe our modification in this article and hypothesize that this should further improve graft vascularization and ligamentization.
A
nterior cruciate ligament (ACL) reconstruction with preservation of the remnant is performed with the hope of improving the vascularization and proprioceptive function of the graft.1-4 Remnant preservation is technically difficult because it hinders the visualization of the intra-articular tunnel site and tip of the guide pin.1 When the remnant is not attached to the femoral ACL footprint, the tibial stump may be preserved.1 Taking a cue from the concept of tibial stump preservation, we have modified our ACL reconstruction technique and we also preserve the ACL stump and soft tissue attached to the femoral condyle, in addition to tibial stump preservation. However, it is difficult to accurately position the tunnel or socket on the femoral side by an inside-out technique unless the soft tissue and ACL stump overlying the medial surface of the lateral femoral condyle are removed using a shaver or radiofrequency probe to completely expose the ACL footprint site. To solve this difficulty, we use a method to preserve this ACL stump attached to the femoral
From the Department of Orthopaedics, All India Institute of Medical Sciences (H.L.N., H.G.), New Delhi, India; and the Department of Orthopaedics, Glasgow Royal Infirmary (H.G.), Glasgow, Scotland. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received March 17, 2014; accepted June 17, 2014. Address correspondence to H. L. Nag, M.S.Orth., Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, 110029, India. E-mail: [email protected] Ó 2014 by the Arthroscopy Association of North America 2212-6287/14222/$36.00 http://dx.doi.org/10.1016/j.eats.2014.06.012
condyle in such a way that it still allows adequate visualization of the femoral ACL insertion site. This step can be added to one’s preferred technique of ACL reconstruction using any fixation method and graft type.
Technique
The patient is placed supine with the hip flexed at about 50 and knee flexed at about 100 . The portals (far anteromedial and anterolateral) are prepared in the usual way. With the arthroscope inserted through the anterolateral portal, a diagnostic arthroscopy is performed. The tibial ACL stump is assessed, and extra tissue is removed with an arthroscopic shaver or punch to leave a short stump of ACL tissue at the ACL footprint on the tibia (Video 1). If the remnant of the ACL is attached to the posterior cruciate ligament (PCL) surface or if there is fibrosis in the region between the PCL and the lateral femoral condyle, it is removed with a shaver inserted through the far anteromedial portal until the PCL is exposed. However, the ACL stump and soft tissue attached to the medial wall of the lateral femoral condyle are not removed. Instead, this tissue is elevated gently as a flap. To achieve this, with the knee kept at 100 of flexion, an arthroscopic liberator knife (ConMed Linvatec, Largo, FL) is inserted through the far anteromedial portal, and beginning from the resident’s ridge, the tissues are lifted off the bone of the medial wall of the lateral condyle (in the same way in which one would elevate the periosteum off the surface of a bone). This needs to be performed very gently and patiently, with the surgeon making sure that the tissues do not become fragmented. Working backward, this
Arthroscopy Techniques, Vol 3, No 5 (October), 2014: pp e575-e577
e575
e576
H. L. NAG AND H. GUPTA
soft tissue “flap” is lifted all the way to the osteochondral junction at the back until the bone is completely exposed at the ACL attachment site on the femoral condyle (Fig 1). This sheet of soft tissue, which is elevated, is left attached at the back. Through the far anteromedial portal, a medial transportal femoral offset guide (Arthrex, Naples, FL) of appropriate size is inserted and placed on the femoral ACL footprint site, keeping the elevated flap behind the offset guide. A femoral guide pin is inserted through the offset guide and drilled into the femur. The femoral socket (or tunnel, depending on the method of fixation chosen by the surgeon) is prepared over the pin in an inside-out manner. The surgeon needs to make sure that the soft-tissue flap does not become entangled with the guide pin or the drill (Fig 2). The tibial tunnel is prepared next, and graft passage and fixation are performed using standard methods. Before insertion of the graft, the soft-tissue flap is gently held with a tissue grasper to check that the flap is intact and to straighten it out. This helps in the smooth passage of the graft into the femoral tunnel or socket under direct arthroscopic vision; otherwise, the soft tissue, which has been harvested so carefully and patiently, will be caught and dragged along with the graft into the tunnel or socket, defeating the whole purpose. After reconstruction of the ligament, the soft-tissue flap, which is still attached at the back of the osteochondral junction, falls back over the posterosuperior aspect of the proximal part of the graft, and it is hypothesized that it should help in vascularization of the graft.
Fig 1. The left knee is being operated on, and the patient is lying supine with the hip flexed at about 50 and knee flexed at about 100 . The viewing portal is the anterolateral portal. The ACL stump is being elevated from the femoral condyle as a soft-tissue sheet using a tissue liberator.
Fig 2. The femoral socket has been prepared (with the same positioning as used in Fig 1). The soft-tissue sleeve is held with a tissue grasper to show how it will fall back over the posterosuperior aspect of the reconstructed ACL.
Discussion We describe a modification of standard ACL reconstruction methods involving preservation of the femoral-side ACL stump. Many clinical studies have shown potential benefit of remnant preservation in ACL reconstruction. This has been summed up by 2 recently published reviews, although both of them concluded that the current level of evidence is not strong enough to conclusively prove the superiority or advantage of remnant-preserving reconstruction techniques as compared with conventional techniques.3,4 When a continuous ACL remnant is available, its preservation has been shown to improve vascularization of the ACL graft, blood flow, ligamentization, tendon-to-bone integration, and proprioceptive function.3-6 Such improvement has also been suggested with even tibial stump preservation in cases in which there is no continuous remnant between the femur and tibia.1,2,7,8 Morphologically normal mechanoreceptors have been shown to be present in both tibial and femoral ACL stumps biopsied during ACL reconstructions.9,10 Preservation of a 2-mm ACL stump on the tibial side in a rabbit model has been shown to increase the number of vessels, as well as blood flow, in the ACL graft.7,8 The same authors also showed increased ligamentization, remodeling, tendon-to-bone integration, and biomechanical strength of the graft in a rabbit model with tibial stump preservation compared with that with complete removal of the ACL stump by cauterization.7,8 On the basis of all these reports, we hypothesize that the preservation of the femoral ACL stump that we have described should further improve graft vascularization and ligamentization.
e577
PRESERVATION OF FEMORAL ACL STUMP
There is some confusion in the literature in terms of terminology between a remnant and a stump. The term “ACL remnant” has been used to signify both a continuous strand of tissue between the tibia and the notch (or the PCL) even with a complete ACL deficiency,1,11 as well as the stump of the ACL tissue left at the tibial (or femoral) attachment site.2,7,8,12 These 2 concepts need to be clearly differentiated in the literature to aid in summarizing the results of different studies. We suggest that the term “remnant” may be used for the former (a continuous strand) and the term “stump” may be used for the latter to avoid confusion. Attempts to preserve the femoral ACL stump may compromise exposure for accurate positioning of the femoral socket and make the operation more challenging.3,13 In our technique, we elevate the available thin layer of tissue including the remnant of the ACL with gentle dissection over the femoral condyle, leaving it attached at the back, and then the tunnel or socket is made directly on the bone and not through the soft tissues. On the other hand, on the tibial side, the tunnel is made through the ACL remnant itself. In this way, one can understand the technical difficulty in preserving the soft-tissue flap until the passage and final fixation of the graft. Our method of preserving the ACL stump on the femoral side does not compromise visualization. Another potential concern with preserving the femoral ACL stump is impingement between the graft and the notch.3 Gohil et al.13 reported a 59% incidence of cyclops formation after ACL reconstruction with minimal debridement of the notch tissue compared with 37.5% in patients with standard debridement (although the difference did not reach statistical significance). However, the flap of soft tissue that we have described lies posterosuperior to the proximal part of the graft; thus it cannot cause any impingement. We could confirm this in our patients at the completion of surgery by visualizing the notch through the anterolateral portal while the knee was moved through a complete range of motion. Most ACL reconstructions are carried out after a period of gap after the initial injury, at which time the quality of this soft tissue overlying the medial wall of the lateral femoral condyle is thin and tends to become fragmented or detached easily. The look of the femoral condyle is deceptive at times in the sense that one may think that there is no soft tissue left for lifting as a flap. However, from our experience with this method, as one starts lifting the stump patiently, it is encouraging to continue it further. Initially, one may find it difficult to create the flap of soft tissues, but we have found that it becomes easy with practice. Furthermore, even if one does not find it happening, there is no harm to the patient because these remnant soft tissues at the
site are removed either with a shaver or thermal cautery.
References 1. Ochi M, Abouheif MM, Kongcharoensombat W, Nakamae A, Adachi N, Deie M. Double bundle arthroscopic anterior cruciate ligament reconstruction with remnant preserving technique using a hamstring autograft. Sports Med Arthrosc Rehabil Ther Technol 2011;3:30. 2. Lee B-I, Kwon S-W, Kim J-B, Choi H-S, Min K-D. Comparison of clinical results according to amount of preserved remnant in arthroscopic anterior cruciate ligament reconstruction using quadrupled hamstring graft. Arthroscopy 2008;24:560-568. 3. Papalia R, Franceschi F, Vasta S, Di Martino A, Maffulli N, Denaro V. Sparing the anterior cruciate ligament remnant: Is it worth the hassle? Br Med Bull 2012;104: 91-111. 4. Song G-Y, Zhang H, Zhang J, et al. The anterior cruciate ligament remnant: To leave it or not? Arthroscopy 2013;29: 1253-1262. 5. Adachi N, Ochi M, Uchio Y, Sumen Y. Anterior cruciate ligament augmentation under arthroscopy. A minimum 2-year follow-up in 40 patients. Arch Orthop Trauma Surg 2000;120:128-133. 6. Löcherbach C, Zayni R, Chambat P, Sonnery-Cottet B. Biologically enhanced ACL reconstruction. Orthop Traumatol Surg Res 2010;96:810-815. 7. Wu B, Zhao Z, Li S, Sun L. Preservation of remnant attachment improves graft healing in a rabbit model of anterior cruciate ligament reconstruction. Arthroscopy 2013;29:1362-1371. 8. Sun L, Wu B, Tian M, Liu B, Luo Y. Comparison of graft healing in anterior cruciate ligament reconstruction with and without a preserved remnant in rabbits. Knee 2013;20:537-544. 9. Dhillon MS, Bali K, Vasistha RK. Immunohistological evaluation of proprioceptive potential of the residual stump of injured anterior cruciate ligaments (ACL). Int Orthop 2010;34:737-741. 10. Bali K, Dhillon MS, Vasistha RK, Kakkar N, Chana R, Prabhakar S. Efficacy of immunohistological methods in detecting functionally viable mechanoreceptors in the remnant stumps of injured anterior cruciate ligaments and its clinical importance. Knee Surg Sports Traumatol Arthrosc 2012;20:75-80. 11. Nakamae A, Ochi M, Deie M, et al. Biomechanical function of anterior cruciate ligament remnants: How long do they contribute to knee stability after injury in patients with complete tears? Arthroscopy 2010;26:1577-1585. 12. Lee B-I, Min K-D, Choi H-S, Kim J-B, Kim S-T. Arthroscopic anterior cruciate ligament reconstruction with the tibial-remnant preserving technique using a hamstring graft. Arthroscopy 2006;22:340.e1-340.e7. 13. Gohil S, Annear PO, Breidahl W. Anterior cruciate ligament reconstruction using autologous double hamstrings: A comparison of standard versus minimal debridement techniques using MRI to assess revascularisation. A randomised prospective study with a one-year follow-up. J Bone Joint Surg Br 2007;89:1165-1171.
