Evolution of tunnel placement in ACL reconstruction
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The document discusses the evolution and significance of tunnel placement in anterior cruciate ligament (ACL) reconstruction, emphasizing the transition from isometric to anatomic techniques. It highlights studies showing that nonanatomic graft placements are common in failed reconstructions, while anatomic placements improve knee kinematics and stability. A comparison of different placement methods reveals variability in tunnel location and technique, with anatomical positions offering better outcomes regarding graft tension and knee stability.
Evolution of tunnel placement in ACL reconstruction
- 1. EVOLUTION OF TUNNEL PLACEMENT IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: FROM ISOMETRIC TO ANATOMIC Dr Dhananjaya Sabat Assistant Professor Maulana Azad Medical College & SushrutaTrauma Center, New Delhi
- 2. Tunnel placement is the most important factor for successful result: WHY? Marchant BG, Noyes FR, Westin SDB, Fleckenstein C. Prevalence of Nonanatomical Graft Placement in a Series of Failed Anterior Cruciate Ligament Reconstructions. Am J Sports Med October 2010 vol. 38 no. 10 1987-1996 • 88% nonanatomic graft placement • 61% of the grafts were entirely on the intercondylar femoral roof • 35% extended posterior to the ACL tibial attachment. • Transtibial technique had been used in 83%: significantly increased vertical orientation of graft In this series comprising 112 revision ACLR
- 3. Zantop T, Kubo S, Petersen W, Musahl V, Fu FH. Current Techniques in Anatomic Anterior Cruciate Ligament Reconstruction. Arthroscopy: The Journal of Arthroscopic and Related Surgery. 2007,23,9:938-947 • 20 panelist worldwide. • Femoral AM bundle tunnel placement : consistent among the panelists. • Femoral PL bundle placement: greater variance in tunnel placement. • 50% -Transtibial AM bundle tunnel • 55% use aimers • 55% do AM tunnel drilling first
- 4. ISOMETRIC CONCEPT Concept : full range of knee can be achieved w/o causing long-term ligament deformation. Authors tried to define the isometric point….. But: Isometry can not exist because, during ROM, there is no one point on femur that maintains a fixed distance from a single point on tibia Elongation always will occur
- 5. ISOMETRIC TIBIAL TUNNEL Tibial aimer fixed at 550 is seated on the debrided stump of the ACL. Center of tunnel is at 7 mm anterior to the PCL notch/ posterior fovea / retroeminentia ridge; in line with the posterior border of the anterior horn of lateral meniscus Outside entry: 4 cm from tibial joint line, 2cm medial to tibial tubercle Morgan CD, KalmanVR, Grawl DM. Definitive landmarks for reproducible tibial tunnel placement in anterior cruciate ligament reconstruction. Arthroscopy 1995;11:275-288 Jackson DW, Gasser SI.Tibial tunnel placement in ACL reconstruction. Arthroscopy 1994;10:124-131
- 6. ISOMETRIC FEMORAL TUNNEL Transtibial technique Center of tunnel at “over the top” position 6-8 mm anterior to the true back wall; i.e. extreme posterior cortex; at the junction of the roof and the lateral wall of the femoral intercondylar notch, resulting in a 1-2mm proximal cortical margin (back wall thickness). Morgan CD, KalmanVR, Grawl DM. Definitive landmarks for reproducible tibial tunnel placement in anterior cruciate ligament reconstruction. Arthroscopy 1995;11:275-288 McGuire DA, Hendricks SD, Grinstead GL. Use of an endoscopic aimer for femoral tunnel placement in anterior cruciate ligament reconstruction. Arthroscopy 1996;12:26-31. Hardin G, Bach B, Bush-Joseph C, Farr J. Endoscopic single incision ACL reconstruction using patellar tendon autograft: surgical technique. Am J Knee Surg1992;5:144-155.
- 7. Which bundle regions of ACL are most isometric Graft placed as closely as possible to centers of tibial & femoral attachments of AM bundle results in least amount of strain (least change in length of ACL during complete ROM of knee) Many surgeons feel that it is more important to replace the more non-isometric PL bundle Focus shifted…… Penner DA, Daniel DM, Wood P, Mishra D. An in vitro study of anterior cruciate ligament graft placement and isometry. Am J Sports Med June 1988 vol. 16 no. 3 238-243
- 8. Anatomic or Isometric??? A femoral tunnel position inside the anatomical footprint of the ACL results in knee kinematics closer to the intact knee than does a tunnel position located for best graft isometry MusahlV, Plakseychuk A,VanScyoc A, SasakiT, Debski RE, McMahon PJ, Fu FH. Varying FemoralTunnels Between the Anatomical Footprint and Isometric PositionsEffect on Kinematics of the Anterior Cruciate Ligament–Reconstructed Knee. AJSM(2005),33,5,712-8
- 9. Anatomic ACLR better restores anterior translational as well as rotational stability. ZavrasTD, Race A, Amis AA.The effect of femoral attachment location on anterior cruciate ligament reconstruction: graft tension patterns and restoration of normal anterior-posterior laxity patterns. KSSTA 2005;13:92-100.
- 10. 10 O’ Clock / 11 O’ Clock !!!! The 10 o’clock position more effectively resists rotatory loads when compared with the 11 o’clock position as evidenced by smaller ATT and higher in situ force Loh JC, FukudaY, Tsuda E, Richard J. Knee Stability and Graft Function Following Anterior Cruciate Ligament Reconstruction: Comparison Between 11 O’clock and 10 O’clock FemoralTunnel Placement. Arthroscopy:The Journal of Arthroscopic and Related Surgery,Vol 19, No 3 (March), 2003: pp 297-304 The clock concept is easy to use. However, it is inaccurate in describing the location of femoral tunnel placement and lead to non-anatomic tunnel position
- 11. Jonsson H, Riklund-Ahlstrom K, Lind J. Positive pivot shift after ACL reconstruction predicts later osteoarthritis: 63 patients followed 5-9 years after surgery. Acta Orthop Scand 2004; 75:594-599. ANATOMIC ACLR BETTER ROTATIONAL STABILITY ? DECREASED RISK OF OSTEOARTHRITIS
- 13. PALMER (1938) - first to describe two bundles, AM & PL Two distinct functional bundles with unique insertion sites demonstrated in fetal, cadaveric and arthroscopic studies. Each bundle is named after its tibial insertion site- AM & PL The AM and PL bundles differ in their length, width, and insertion area INTRA_ ARTICULAR LENGTH INSERTION AREA ON FEMUR INSERTIO N AREA ON TIBIA AM BUNDLE 28-38 mm 44 mm sq 67 mm sq PL BUNDLE 18-20 mm 40 mm sq 52 mm sq
- 14. Yasuda K et al P. Colombet et al. 2006 Zhao J TIBIAL ATTACHMENT More variable
- 15. Arthroscopically Useful Landmarks for Identifying ACL Tibial Footprint A> anterior margin of PCL ACL CENTER AM CENTER PL CENTER Iriuchishima et al.2010 23. 4 mm 12. 3 mm Purnell et al.2008 16.5 ± 2 mm (12.7-19.1 mm) Heming et al.2007 15.0 mm Colombet et al.2006 17.5 ± 1.7 mm Edwards et al.2007 15.2 mm (range, 11-18 mm) 17 .2 mm (13-19 mm) 10 .1 mm (8-13 mm) Hutchinson and Bae2001 10.4 ± 2.4 mm; posterior border - 6.7 ±1.2 mm anterior to PCL Cuomo et al.2006 Anterior border 22.3 mm (16- 27 mm) ; posterior border 6.2 mm (2-8 mm)
- 16. B> lateral Meniscus Zantop et al.2008 From center of anterior insertion of lateral meniscus;AM center is 2.7 ±0.5 mm posterior and 5.2 0.7 mm medial , PL center is 11.2 ±1.2 mm posterior and 4.1 0.6 mm medial Siebold et al.2008 Posterior horn of lateral meniscus is adjacent to posterior border of PL footprint; centrum of PL footprint is 5 mm anterior C> Tibial spine Luites et al.2007 Centrum of AM bundle is one-fourth interspinous distance from ML intercondylar eminence; PL bundle centrum is 4 mm more lateral, approximately halfway between spines; tibial footprint centrum as a whole is two-fifths ML (interspinous distance)
- 17. ANTERIOR HORN OF LATERAL MENISCUS: IS IT A GOOD LANDMARK? NO
- 18. The center of theACL tibial attachment was 9.12 ± 1.54 mm behind the posterior edge of the intermeniscal ligament. The center of the ACL tibial attachment was 5.3 ± 1.14 mm anterior from a projected line from the peak of the medial tibial spine Ferretti M, Doca D, Ingham SM, Cohen M, Fu FH. Bony and soft tissue landmarks of the ACL tibial insertion site: an anatomical study . KSSTA 2011
- 19. RADIOGRAPHIC METHOD The lateral knee radiograph method Amis and Jakob line (1998): line parallel to the medial tibial plateau. Stäubli and Rauschning (1994) : line is perpendicular to the tibial axis Both lines yield similar results AM center at 1/3rd of the AP distance along either line, PL center is at 40 - 50% of the AP distance along either line.
- 20. AP distance wrt AP depth of tibia: AM – 25% (21.1- 29.5), PL- 46.4% ( 40.1-51.5) ML distance wrt ML width of tibia: AM – 50.5% (44.1-54.7), PL – 52.4 (49.5- 56.1) Forsythe B, Kopf S, Wong AK, Martins CAQ, Anderst W, Tashman S, Fu FH. The location of femoral and tibial tunnels in anatomical double bundle anterior cruciate ligamnet reconstruction analyzed by three dimensional computed tomography models. JBJS Am.2010;92:1418-26
- 21. FEMORAL ATTACHMENT More consistent P. Colombet et al. 2006
- 22. The AM and PL bundles change from being parallel in extension to crossing in flexion
- 23. Arthroscopically Useful Landmarks for Identifying ACL Femoral Footprint Arthroscopic landmarks are less useful: parallax, which occurs when viewing with an 30 degree arthroscopic camera variability in the size of diverse femora Useful landmarks: femoral ACL stump (Footprint) Resident’s ridge Better visualization through AM portal 70 degree scope
- 24. Two osseous landmarks: the lateral intercondylar ridge and the lateral bifurcate ridge. When the knee is in 90· of flexion, the lateral intercondylar ridge runs through the entire ACL footprint with no ACL fibers attaching superior to this ridge. The lateral bifurcate ridge runs almost perpendicular to the lateral intercondylar ridge and separates the AM and PL bundle femoral insertion sites.
- 25. Ruler Method “Mid Bundle Reconstruction” In the absence of consistent intra-operative visualisation or landmarks The centre of the ACL insertion lies at a point 50% along a line drawn from the proximal articular cartilage border and the distal articular cartilage parallel to the tibial surface, with the knee at 90 degree Validation of a new technique to determine midbundle femoral tunnel position in anterior cruciate ligament reconstruction using 3-dimensional computed tomography analysis. Bird JH, Carmont MR, Dhillon M, Smith N, Brown C, Thompson P, SpaldingT. Arthroscopy. 2011 Sep;27(9):1259-67.
- 26. RADIOGRAPHIC METHOD Bernard and Hertel method: the centrum as % distance along the Blumensaat line (from proximal and posterior to distal and anterior) by % distance along a line perpendicular to the Blumensaat line (from proximal and anterior to distal and posterior). Mochizuki method Edward method Takahashi method The mean ratio between the AP femur measurement and the center of the ACL femoral attachment -74 to 80%. Jenny JY , Ciobanu E, Philippe Clavert P, Jaeger JH, Kahn JL, Kempf JF. Anatomic attachment of the ACL. Comparison between radiological and CT analysis . Knee Surg Sports Traumatol Arthrosc (2011) 19:806–810
- 27. By quadrant method: AM Bundle PL bundle Parallel to Blumensaat Perpendicular to Blumensaat Parallel to Blumensaat Perpendicular to Blumensaat Forsythe et al 21.7 % 33.2% 35.1% 55.3% Zantop et al 18.5% 22.3% 29.3% 53.6%
- 28. In summary… ACL center: 43% of the proximal-to-distal length of the lateral, femoral intercondylar notch wall and femoral socket radius + 2.5 mm anterior to the posterior articular margin. AM center: 29.5% of the proximal-to-distal length of the lateral, femoral intercondylar notch wall. PL center : 50% of the proximal-to-distal length of the lateral, femoral intercondylar notch wall. From posterior to anterior, the AM bundle appears slightly anterior to the PL bundle, and both bundles appear socket radius + 2.5 mm anterior to the posterior cartilage margin. Kaseta MK, DeFrate LE, Charnock BL, Sullivan RT, Garrett WE. Reconstruction technique affects femoral tunnel placement in ACL reconstruction. Clin Orthop Relat Res 2008;466: 1467-1474.
Editor's Notes
- #3: Why tunnel placement is important? In this series published in AmJSM comprising 112 revision ACLR – 88% graft placement was nonanatomic.
- #4: In this interesting study published in 2007, 20 panelists worldwide were asked to mark the area where they would like to place the tunnels in ACLR on the femur.
- #5: Isometric positioning of the ACL graft or prosthesis is an important consideration in successful reconstruction of the ACL-deficient knee. But: In cadaveric studies, a true isometric point could not be located as during ROM, there is no one point on femur that maintains a fixed distance from a single point on tibia.
- #8: So now researchers have tried to determine which bundle regions of ACL are most isometric? It was noted in cadaveric studies that the centers of tibial & femoral attachments of AM bundle is close to isometric point. But many surgeons feel that it is more important to replace the more non-isometric PL bundle as it has more role in roatational stability.