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Location, Location, Location Brett D. Owens Am J Sports Med 2013 41: 2481 DOI: 10.1177/0363546513511052 The online version of this article can be found at: http://ajs.sagepub.com/content/41/11/2481
Published by: http://www.sagepublications.com
On behalf of: American Orthopaedic Society for Sports Medicine
Additional services and information for The American Journal of Sports Medicine can be found at: Email Alerts: http://ajs.sagepub.com/cgi/alerts Subscriptions: http://ajs.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> Version of Record - Nov 1, 2013 What is This?
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Editorial
Location, Location, Location malposition is the principal technical cause of failure of primary reconstruction. Morgan and colleagues14 reported that femoral tunnel malposition was noted as the only cause of technical failure in 39% of failed cases, and as one of the causes in an additional 33%. Among many studies published challenging the ‘‘high’’ position, Musahl and colleagues15 presented their cadaveric study comparing the ‘‘anatomic’’ position and the high position, and found that anatomic placement resulted in knee kinematics closer to that of the intact knee (but not equal) compared with the high position. Multiple cadaveric studies have shown that transtibial drilling can result in anatomic placement within the femoral footprint of the ACL, although not as reliably compared with other techniques. Tompkins and colleagues18 found that transtibial drilling resulted in a femoral tunnel aperture with only 61% within the anatomic footprint and the tunnel center a mean distance of 6 mm from the anatomic footprint center. Miller et al13 performed a similar cadaveric study and showed that transtibial femoral drilling resulted in larger tibial tunnel apertures. Bowers and colleagues3 showed that transtibial drilling may provide femoral tunnels close to the anatomic centroid, but this may come at the cost of a tibial tunnel that is drilled 5 mm posterior to the tibial centroid. If ideal tunnel placement may not always be possible with transtibial drilling of the femoral tunnel, what other options do surgeons have? Two alternatives of femoral independent drilling have been explored, one that preceded transtibial drilling and one a more recent development. The first has been termed the ‘‘outside-in’’ approach and has origins in the 2-incision technique. While the rear-entry guide can still be used through a femoral incision, newer reverse-cutting guides have allowed this to be performed in a percutaneous manner. The second option is drilling through an accessory anteromedial portal, the popularity of which has flourished during the recent decade. A recent survey showed a clear change in surgical technique with 63% of North American surgeons and 81% of surgeons worldwide preferring drilling through an anteromedial portal.6 These approaches have been evaluated with cadaveric models, with McConkey and colleagues11 finding femoral tunnels were ideal 86% of time using 2-incision technique, 66% of time using the anteromedial portal, and only 51% of the time with transtibial technique. Similar findings were shown by Gadikota and colleagues,9 with significantly more of the femoral tunnel within the ACL footprint for anteromedial portal (86%) and outside-in (89%) techniques compared with the transtibial technique (73%). In addition to having learning curves, both of these femoral-independent techniques have potential downsides. There are concerns about the inability to obtain aperture fixation because of the tunnel angle using the outside-in technique. The anteromedial
There are three things that matter in property: location, location, location. —Lord Harold Samuel In real estate, the importance of location is paramount. A run-down ‘‘fixer-upper’’ that is in the heart of the downtown or is waterfront can demand a selling price much higher than a similar property in a less desirable ‘‘location.’’ While location is not the only variable that influences the pricing of a property, it is one of the most important. Similarly, the location of graft tunnels in ACL surgery is the subject of intense study and debate. While other variables exist that can influence patient outcome, tunnel location is entirely controllable by the surgeon; thus, placing the graft in the optimal location is considered critical to a successful reconstruction. In the early 1980s, technological advances allowed for ACL reconstructions to be performed in an ‘‘arthroscopicassisted’’ fashion. The tibial side was drilled with a technique similar to the current technique, while the femoral side was drilled using a rear-entry guide placed through a lateral femoral incision—termed the ‘‘2-incision’’ approach.4 The early 1990s saw the rise of the ‘‘endoscopic’’ approach—in which the femoral tunnel was drilled through the tibial tunnel.12 The endoscopic approach increased in popularity due to the improved cosmesis and decreased morbidity, as well as the inherent appeal of performing an ‘‘all-arthroscopic’’ technique.12 The transition from a 2-incision ACL reconstruction to an endoscopic technique involved preparing the femoral socket using transtibial drilling. The over-the-top guide is placed through the drilled tibial tunnel and hooked over the roof of the intercondylar notch, ensuring an adequate posterior wall to the femoral socket.2 This guide was designed to prevent posterior femoral cortical blow-out, but also tended to encourage somewhat vertical placement of the graft. This approach allowed for the avoidance of the femoral incision and became the most popular approach for ACL reconstruction during the 1990s. The trend continued well into the next decade, with a 2006 survey reporting that the majority (85%) of surgeons in the United States employed transtibial drilling.7 Over the past decade, continued striving for improvements in our patient outcomes as well a renewed appreciation of the anatomy of the ACL footprint anatomy resulted in challenging of this ‘‘high’’ femoral tunnel position typically associated with the endoscopic technique as being nonanatomic. Early data from the Multicenter ACL Revision Study (MARS) cohort suggest that femoral tunnel
The American Journal of Sports Medicine, Vol. 41, No. 11 DOI: 10.1177/0363546513511052 Ó 2013 American Orthopaedic Society for Sports Medicine
2481 Downloaded from ajs.sagepub.com at Bibliothekssystem der Universitaet Giessen on May 5, 2015
2482 Editorial
The American Journal of Sports Medicine
portal technique results in shorter femoral tunnels,5 which may have implications for fixation, especially with suspension devices. In addition to cadaveric work, radiographic assessments of ACL reconstruction patients had similar findings. One such study analyzed 30 patients undergoing either transtibial or anteromedial portal drilling for ACL reconstruction with postoperative MRI and found no differences in femoral tunnel centroids but found that the anteromedial portal technique resulted in grafts with more sagittal obliquity (52.2° vs 53.5° for native ACL) compared with the transtibial technique (66.9°).3 Illingworth and colleagues10 studied 50 ACL patients with MRI and CT scans. They also found greater sagittal obliquity with femoral independent techniques—51.8° compared with 63.5° for the transtibial tunnels. They found greater obliquity in the coronal plane also—37.6° for femoral-independent drilling techniques vs 14.2° for transtibial. Shin and colleagues17 report similar findings in another radiographic clinical study in this issue. They analyzed postreconstruction CT scans on 142 patients and found that femoral-independent techniques (anteromedial portal and outside-in) resulted in significantly ‘‘lower’’ femoral tunnels in the coronal plane than did transtibial drilled tunnels. However, clinical data are still lacking. In this issue, Riboh and colleagues16 present a systematic review on this subject and determine that while biomechanical data suggest more anatomic graft placement is possible and provides increased stability in the laboratory, clinical data on superiority of patient outcomes remains absent. In a nonrandomized study in our August issue this year, Wang and colleagues19 reported on knee kinematics following ACL reconstruction with either transtibially drilled or anteromedial portal femoral tunnels. The group undergoing anteromedial portal drilling had better restoration of anterior-posterior translation as well external rotation during walking. The critical question remains: Is clinical outcome improved with independent femoral drilling techniques compared with transtibial? A nonrandomized retrospective study of 94 patients undergoing either transtibial or anteromedial portal drilling by a single surgeon showed significant improvement in stability by Lachman and pivot-shift grades, and nonsignificant trends in IKDC, Lysholm, and return-to-sport level, all favoring the anteromedial portal technique.8 A recent meta-analysis of prospective studies of bone–patellar tendon–bone ACL reconstruction in which the drilling technique was clearly identified as transtibial or anteromedial portal had mixed findings.1 The laxity, as measured by Lachman and KT-1000 values, was improved in the anteromedial portal patients compared with transtibial at 1 to 2 years, but this advantage was not apparent with the 3- to 5-year and 6- to 10-year intervals. The transtibial group demonstrated a higher reported activity level at the 3- to 5- and 6- to 10-year marks. However, no significant differences in IKDC or Lysholm scores were noted between these groups among the 21 studies and 859 patients involved in this analysis.1 So what does all this work mean for the ACL surgeon? The principles of ACL surgery have not changed. The
emphasis on accurate placement of tunnels at the anatomic footprints continues; the placement of the femoral tunnel in the ‘‘anatomic’’ footprint of the ACL can be achieved with many techniques. Optimal tunnel placement is one of many variables that the surgeon must control to optimize the chances for a successful reconstruction. Surgeons need to be aware of why the ‘‘current’’ preferred techniques exist and how these changes came to pass. We also need to be facile with the various options of femoral tunnel drilling, as certain cases (pediatric patients, revision reconstruction, etc) may be best treated by a method that is different from our usual technique. We must learn to be critical of our tunnel’s ‘‘location’’ and strive for optimal placement as, unlike the real estate market, this is a variable we can control.
Brett D. Owens, MD Associate Editor West Point, New York REFERENCES 1. Alentorn-Geli E, Lajara F, Samitier G, Cugat R. The transtibial versus the anteromedial portal technique in the arthroscopic bone-patellar tendon-bone anterior cruciate ligament reconstruction. Knee Surg Sport Traumatol Arthrosc. 2010;18:1013-1037. 2. Bach BR Jr, Levy ME, Bojchuk J, Tradonsky S, Bush-Joseph CA, Khan NH. Single-incision endoscopic anterior cruciate ligament reconstruction using patellar tendon autograft. Minimum two-year follow-up evaluation. Am J Sports Med. 1998;26(1):30-40. 3. Bowers AL, Bedi A, Lipman JD, et al. Comparison of anterior cruciate ligament tunnel position and graft obliquity with transtibial and anteromedial portal femoral tunnel reaming techniques using high-resolution magnetic resonance imaging. Arthroscopy. 2011;27(11):1511-1522. 4. Chambat P, Guier C, Sonnery-Cottet B, Fayard JM, Thaunat M. The evolution of ACL reconstruction over the last fifty years. Int Orthop. 2013;37(2):181-186. 5. Chang MJ, Chang CB, Won HH, Je MS, Kim TK. Anteromedial portal versus outside-in technique for creating femoral tunnels in anatomic anterior cruciate ligament reconstructions. Arthroscopy. 2013;29(9): 1533-1539. 6. Chechik O, Amar E, Khashan M, Lador R, Eyal G, Gold A. An international survey on anterior cruciate ligament reconstruction practices. Int Orthop. 2013;37(2):201-206. 7. Duquin TR, Wind WM, Fineberg MS, Smolinski RJ, Buyea CM. Current trends in anterior cruciate ligament reconstruction. J Knee Surg. 2009;22(1):7-12. 8. Franceschi F, Papalia R, Rizzello G, Del Buono A, Maffulli N, Denaro V. Anteromedial portal versus transtibial drilling techniques in anterior cruciate ligament reconstruction: any clinical relevance? Arthroscopy. 2013;29(8):1330-1337. 9. Gadikota HR, Sim JA, Hosseini A, Gill TJ, Li G. The relationship between femoral tunnels created by the transtibial, anteromedial portal, and outside-in techniques and the anterior cruciate ligament footprint. Am J Sports Med. 2012;40(4):882-888. 10. Illingworth KD, Hensler D, Working ZM, Macalena JA, Tashman S, Fu FH. A simple evaluation of anterior cruciate ligament femoral tunnel position: the inclination angle and femoral tunnel angle. Am J Sports Med. 2011;39(12):2611-2618. 11. McConkey MO, Amendola A, Ramme AJ, et al. Arthroscopic agreement among surgeons on anterior cruciate ligament tunnel placement. Am J Sports Med. 2012;40(12):2737-2746.
Downloaded from ajs.sagepub.com at Bibliothekssystem der Universitaet Giessen on May 5, 2015
Vol. 41, No. 11, 2013
Location, Location, Location
12. McCulloch PC, Lattermann C, Boland AL, Bach BR Jr. An illustrated history of anterior cruciate ligament surgery. J Knee Surg. 2007;20(2): 95-104. 13. Miller MD, Gerdeman AC, Miller CD, et al. The effects of extraarticular starting point and transtibial femoral drilling on the intraarticular aperture of the tibial tunnel in ACL reconstruction. Am J Sports Med. 2010;38(4):707-712. 14. Morgan JA, Dahm D, Levy B, Stuart MJ, MARS. Femoral tunnel malposition in ACL revision reconstruction. J Knee Surg. 2012;25(5):361-368. 15. Musahl V, Plakseychuk A, VanScyoc A, et al. Varying femoral tunnels between the anatomical footprint and isometric positions: effect on kinematics of the anterior cruciate ligament–reconstructed knee. Am J Sports Med. 2005;33(5):712-718. 16. Riboh JC, Hasselblad V, Godin JA, Mather RC 3rd. Transtibial versus independent drilling techniques for anterior cruciate reconstruction:
2483
a systematic review, meta-analysis, and meta-regression. Am J Sports Med. 2013;41(11):2693-2702. 17. Shin YS, Ro KH, Lee JH, Lee DH. Location of the femoral tunnel aperture in single-bundle anterior cruciate ligament reconstruction: comparison of the transtibial, anteromedial portal, and outside-in techniques. Am J Sports Med. 2013;41(11):2533-2539. 18. Tompkins M, Milewski MD, Brockmeier SF, Gaskin CM, Hart JM, Miller MD. Anatomic femoral tunnel drilling in anterior cruciate ligament reconstruction: use of an accessory medial portal versus traditional transtibial drilling. Am J Sports Med. 2012;40(6):13131321. 19. Wang H, Fleischli JE, Zheng NN. Transtibial versus anteromedial portal technique in single-bundle anterior cruciate ligament reconstruction: outcomes of knee joint kinematics during walking. Am J Sports Med. 2013;41(8):1847-1856.
For reprints and permission queries, please visit SAGE’s Web site at http://www.sagepub.com/journalsPermissions.nav
Downloaded from ajs.sagepub.com at Bibliothekssystem der Universitaet Giessen on May 5, 2015
Location, Location, Location Brett D. Owens Am J Sports Med 2013 41: 2481 DOI: 10.1177/0363546513511052 The online version of this article can be found at: http://ajs.sagepub.com/content/41/11/2481
Published by: http://www.sagepublications.com
On behalf of: American Orthopaedic Society for Sports Medicine
Additional services and information for The American Journal of Sports Medicine can be found at: Email Alerts: http://ajs.sagepub.com/cgi/alerts Subscriptions: http://ajs.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> Version of Record - Nov 1, 2013 What is This?
Downloaded from ajs.sagepub.com at Bibliothekssystem der Universitaet Giessen on May 5, 2015
Editorial
Location, Location, Location malposition is the principal technical cause of failure of primary reconstruction. Morgan and colleagues14 reported that femoral tunnel malposition was noted as the only cause of technical failure in 39% of failed cases, and as one of the causes in an additional 33%. Among many studies published challenging the ‘‘high’’ position, Musahl and colleagues15 presented their cadaveric study comparing the ‘‘anatomic’’ position and the high position, and found that anatomic placement resulted in knee kinematics closer to that of the intact knee (but not equal) compared with the high position. Multiple cadaveric studies have shown that transtibial drilling can result in anatomic placement within the femoral footprint of the ACL, although not as reliably compared with other techniques. Tompkins and colleagues18 found that transtibial drilling resulted in a femoral tunnel aperture with only 61% within the anatomic footprint and the tunnel center a mean distance of 6 mm from the anatomic footprint center. Miller et al13 performed a similar cadaveric study and showed that transtibial femoral drilling resulted in larger tibial tunnel apertures. Bowers and colleagues3 showed that transtibial drilling may provide femoral tunnels close to the anatomic centroid, but this may come at the cost of a tibial tunnel that is drilled 5 mm posterior to the tibial centroid. If ideal tunnel placement may not always be possible with transtibial drilling of the femoral tunnel, what other options do surgeons have? Two alternatives of femoral independent drilling have been explored, one that preceded transtibial drilling and one a more recent development. The first has been termed the ‘‘outside-in’’ approach and has origins in the 2-incision technique. While the rear-entry guide can still be used through a femoral incision, newer reverse-cutting guides have allowed this to be performed in a percutaneous manner. The second option is drilling through an accessory anteromedial portal, the popularity of which has flourished during the recent decade. A recent survey showed a clear change in surgical technique with 63% of North American surgeons and 81% of surgeons worldwide preferring drilling through an anteromedial portal.6 These approaches have been evaluated with cadaveric models, with McConkey and colleagues11 finding femoral tunnels were ideal 86% of time using 2-incision technique, 66% of time using the anteromedial portal, and only 51% of the time with transtibial technique. Similar findings were shown by Gadikota and colleagues,9 with significantly more of the femoral tunnel within the ACL footprint for anteromedial portal (86%) and outside-in (89%) techniques compared with the transtibial technique (73%). In addition to having learning curves, both of these femoral-independent techniques have potential downsides. There are concerns about the inability to obtain aperture fixation because of the tunnel angle using the outside-in technique. The anteromedial
There are three things that matter in property: location, location, location. —Lord Harold Samuel In real estate, the importance of location is paramount. A run-down ‘‘fixer-upper’’ that is in the heart of the downtown or is waterfront can demand a selling price much higher than a similar property in a less desirable ‘‘location.’’ While location is not the only variable that influences the pricing of a property, it is one of the most important. Similarly, the location of graft tunnels in ACL surgery is the subject of intense study and debate. While other variables exist that can influence patient outcome, tunnel location is entirely controllable by the surgeon; thus, placing the graft in the optimal location is considered critical to a successful reconstruction. In the early 1980s, technological advances allowed for ACL reconstructions to be performed in an ‘‘arthroscopicassisted’’ fashion. The tibial side was drilled with a technique similar to the current technique, while the femoral side was drilled using a rear-entry guide placed through a lateral femoral incision—termed the ‘‘2-incision’’ approach.4 The early 1990s saw the rise of the ‘‘endoscopic’’ approach—in which the femoral tunnel was drilled through the tibial tunnel.12 The endoscopic approach increased in popularity due to the improved cosmesis and decreased morbidity, as well as the inherent appeal of performing an ‘‘all-arthroscopic’’ technique.12 The transition from a 2-incision ACL reconstruction to an endoscopic technique involved preparing the femoral socket using transtibial drilling. The over-the-top guide is placed through the drilled tibial tunnel and hooked over the roof of the intercondylar notch, ensuring an adequate posterior wall to the femoral socket.2 This guide was designed to prevent posterior femoral cortical blow-out, but also tended to encourage somewhat vertical placement of the graft. This approach allowed for the avoidance of the femoral incision and became the most popular approach for ACL reconstruction during the 1990s. The trend continued well into the next decade, with a 2006 survey reporting that the majority (85%) of surgeons in the United States employed transtibial drilling.7 Over the past decade, continued striving for improvements in our patient outcomes as well a renewed appreciation of the anatomy of the ACL footprint anatomy resulted in challenging of this ‘‘high’’ femoral tunnel position typically associated with the endoscopic technique as being nonanatomic. Early data from the Multicenter ACL Revision Study (MARS) cohort suggest that femoral tunnel
The American Journal of Sports Medicine, Vol. 41, No. 11 DOI: 10.1177/0363546513511052 Ó 2013 American Orthopaedic Society for Sports Medicine
2481 Downloaded from ajs.sagepub.com at Bibliothekssystem der Universitaet Giessen on May 5, 2015
2482 Editorial
The American Journal of Sports Medicine
portal technique results in shorter femoral tunnels,5 which may have implications for fixation, especially with suspension devices. In addition to cadaveric work, radiographic assessments of ACL reconstruction patients had similar findings. One such study analyzed 30 patients undergoing either transtibial or anteromedial portal drilling for ACL reconstruction with postoperative MRI and found no differences in femoral tunnel centroids but found that the anteromedial portal technique resulted in grafts with more sagittal obliquity (52.2° vs 53.5° for native ACL) compared with the transtibial technique (66.9°).3 Illingworth and colleagues10 studied 50 ACL patients with MRI and CT scans. They also found greater sagittal obliquity with femoral independent techniques—51.8° compared with 63.5° for the transtibial tunnels. They found greater obliquity in the coronal plane also—37.6° for femoral-independent drilling techniques vs 14.2° for transtibial. Shin and colleagues17 report similar findings in another radiographic clinical study in this issue. They analyzed postreconstruction CT scans on 142 patients and found that femoral-independent techniques (anteromedial portal and outside-in) resulted in significantly ‘‘lower’’ femoral tunnels in the coronal plane than did transtibial drilled tunnels. However, clinical data are still lacking. In this issue, Riboh and colleagues16 present a systematic review on this subject and determine that while biomechanical data suggest more anatomic graft placement is possible and provides increased stability in the laboratory, clinical data on superiority of patient outcomes remains absent. In a nonrandomized study in our August issue this year, Wang and colleagues19 reported on knee kinematics following ACL reconstruction with either transtibially drilled or anteromedial portal femoral tunnels. The group undergoing anteromedial portal drilling had better restoration of anterior-posterior translation as well external rotation during walking. The critical question remains: Is clinical outcome improved with independent femoral drilling techniques compared with transtibial? A nonrandomized retrospective study of 94 patients undergoing either transtibial or anteromedial portal drilling by a single surgeon showed significant improvement in stability by Lachman and pivot-shift grades, and nonsignificant trends in IKDC, Lysholm, and return-to-sport level, all favoring the anteromedial portal technique.8 A recent meta-analysis of prospective studies of bone–patellar tendon–bone ACL reconstruction in which the drilling technique was clearly identified as transtibial or anteromedial portal had mixed findings.1 The laxity, as measured by Lachman and KT-1000 values, was improved in the anteromedial portal patients compared with transtibial at 1 to 2 years, but this advantage was not apparent with the 3- to 5-year and 6- to 10-year intervals. The transtibial group demonstrated a higher reported activity level at the 3- to 5- and 6- to 10-year marks. However, no significant differences in IKDC or Lysholm scores were noted between these groups among the 21 studies and 859 patients involved in this analysis.1 So what does all this work mean for the ACL surgeon? The principles of ACL surgery have not changed. The
emphasis on accurate placement of tunnels at the anatomic footprints continues; the placement of the femoral tunnel in the ‘‘anatomic’’ footprint of the ACL can be achieved with many techniques. Optimal tunnel placement is one of many variables that the surgeon must control to optimize the chances for a successful reconstruction. Surgeons need to be aware of why the ‘‘current’’ preferred techniques exist and how these changes came to pass. We also need to be facile with the various options of femoral tunnel drilling, as certain cases (pediatric patients, revision reconstruction, etc) may be best treated by a method that is different from our usual technique. We must learn to be critical of our tunnel’s ‘‘location’’ and strive for optimal placement as, unlike the real estate market, this is a variable we can control.
Brett D. Owens, MD Associate Editor West Point, New York REFERENCES 1. Alentorn-Geli E, Lajara F, Samitier G, Cugat R. The transtibial versus the anteromedial portal technique in the arthroscopic bone-patellar tendon-bone anterior cruciate ligament reconstruction. Knee Surg Sport Traumatol Arthrosc. 2010;18:1013-1037. 2. Bach BR Jr, Levy ME, Bojchuk J, Tradonsky S, Bush-Joseph CA, Khan NH. Single-incision endoscopic anterior cruciate ligament reconstruction using patellar tendon autograft. Minimum two-year follow-up evaluation. Am J Sports Med. 1998;26(1):30-40. 3. Bowers AL, Bedi A, Lipman JD, et al. Comparison of anterior cruciate ligament tunnel position and graft obliquity with transtibial and anteromedial portal femoral tunnel reaming techniques using high-resolution magnetic resonance imaging. Arthroscopy. 2011;27(11):1511-1522. 4. Chambat P, Guier C, Sonnery-Cottet B, Fayard JM, Thaunat M. The evolution of ACL reconstruction over the last fifty years. Int Orthop. 2013;37(2):181-186. 5. Chang MJ, Chang CB, Won HH, Je MS, Kim TK. Anteromedial portal versus outside-in technique for creating femoral tunnels in anatomic anterior cruciate ligament reconstructions. Arthroscopy. 2013;29(9): 1533-1539. 6. Chechik O, Amar E, Khashan M, Lador R, Eyal G, Gold A. An international survey on anterior cruciate ligament reconstruction practices. Int Orthop. 2013;37(2):201-206. 7. Duquin TR, Wind WM, Fineberg MS, Smolinski RJ, Buyea CM. Current trends in anterior cruciate ligament reconstruction. J Knee Surg. 2009;22(1):7-12. 8. Franceschi F, Papalia R, Rizzello G, Del Buono A, Maffulli N, Denaro V. Anteromedial portal versus transtibial drilling techniques in anterior cruciate ligament reconstruction: any clinical relevance? Arthroscopy. 2013;29(8):1330-1337. 9. Gadikota HR, Sim JA, Hosseini A, Gill TJ, Li G. The relationship between femoral tunnels created by the transtibial, anteromedial portal, and outside-in techniques and the anterior cruciate ligament footprint. Am J Sports Med. 2012;40(4):882-888. 10. Illingworth KD, Hensler D, Working ZM, Macalena JA, Tashman S, Fu FH. A simple evaluation of anterior cruciate ligament femoral tunnel position: the inclination angle and femoral tunnel angle. Am J Sports Med. 2011;39(12):2611-2618. 11. McConkey MO, Amendola A, Ramme AJ, et al. Arthroscopic agreement among surgeons on anterior cruciate ligament tunnel placement. Am J Sports Med. 2012;40(12):2737-2746.
Downloaded from ajs.sagepub.com at Bibliothekssystem der Universitaet Giessen on May 5, 2015
Vol. 41, No. 11, 2013
Location, Location, Location
12. McCulloch PC, Lattermann C, Boland AL, Bach BR Jr. An illustrated history of anterior cruciate ligament surgery. J Knee Surg. 2007;20(2): 95-104. 13. Miller MD, Gerdeman AC, Miller CD, et al. The effects of extraarticular starting point and transtibial femoral drilling on the intraarticular aperture of the tibial tunnel in ACL reconstruction. Am J Sports Med. 2010;38(4):707-712. 14. Morgan JA, Dahm D, Levy B, Stuart MJ, MARS. Femoral tunnel malposition in ACL revision reconstruction. J Knee Surg. 2012;25(5):361-368. 15. Musahl V, Plakseychuk A, VanScyoc A, et al. Varying femoral tunnels between the anatomical footprint and isometric positions: effect on kinematics of the anterior cruciate ligament–reconstructed knee. Am J Sports Med. 2005;33(5):712-718. 16. Riboh JC, Hasselblad V, Godin JA, Mather RC 3rd. Transtibial versus independent drilling techniques for anterior cruciate reconstruction:
2483
a systematic review, meta-analysis, and meta-regression. Am J Sports Med. 2013;41(11):2693-2702. 17. Shin YS, Ro KH, Lee JH, Lee DH. Location of the femoral tunnel aperture in single-bundle anterior cruciate ligament reconstruction: comparison of the transtibial, anteromedial portal, and outside-in techniques. Am J Sports Med. 2013;41(11):2533-2539. 18. Tompkins M, Milewski MD, Brockmeier SF, Gaskin CM, Hart JM, Miller MD. Anatomic femoral tunnel drilling in anterior cruciate ligament reconstruction: use of an accessory medial portal versus traditional transtibial drilling. Am J Sports Med. 2012;40(6):13131321. 19. Wang H, Fleischli JE, Zheng NN. Transtibial versus anteromedial portal technique in single-bundle anterior cruciate ligament reconstruction: outcomes of knee joint kinematics during walking. Am J Sports Med. 2013;41(8):1847-1856.
For reprints and permission queries, please visit SAGE’s Web site at http://www.sagepub.com/journalsPermissions.nav
Downloaded from ajs.sagepub.com at Bibliothekssystem der Universitaet Giessen on May 5, 2015
