An anatomical and biomechanical comparison of anteromedial and anterolateral approaches for tibial tunnel of posterior cruciate ligament reconstruction

Evaluation of the widening effect of the anterolateral approach

Jin Hwan Ahn, Ji Hoon Bae, Yong Seuk Lee, Kuiwon Choi, Tae Soo Bae, Joon Ho Wang

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Background: An anterolateral approach to the tibial tunnel of posterior cruciate ligament reconstruction is used to reduce the sharpness of the graft-tunnel angle, the so-called killer turn effect. However, with the anterolateral approach, the tunnel might be widened into an ovoid shape because of the small angle between the tunnel and the anterolateral cortex. Hypothesis: The fixation strength of the posterior cruciate ligament graft in the tibial tunnel will be weaker in the anterolateral approach compared with the anteromedial approach. Study Design: Controlled laboratory study. Methods: Twenty paired cadaveric tibias were used. Tibial tunnels were made using following approaches: an anteromedial approach for 10 tibias and an anterolateral approach for 10 tibias. The anterior cortex-tunnel angle and the diameter of the tunnel entrance were measured by 2-dimensional computed tomographic scans. After fixation of the Achilles tendon allograft with a biodegradable screw, the maximal strength of the graft at failure was measured using a materials testing machine. Results: The mean cortex-tunnel angle was 47.5° ± 9.3° in the anteromedial approach group and 28.3° ± 7.4° in the anterolateral approach group. The mean long diameter of the tunnels in the anteromedial approach group was 10.6 ± 1.0 mm and in the anterolateral approach group it was 14.0 ± 1.5 mm. These two parameters showed statistically significant differences between the 2 groups (P <.01). The mean maximum load at failure for the anteromedial approach group was 385.4 ± 139.7 N, and for the anterolateral approach group it was 225.1 ± 144.1 N. This difference was statistically significant (P =.021). Conclusion: The anterolateral approach resulted in a tunnel with a wider entrance, a more acute cortex-tunnel angle, and a lower maximal load at failure compared with tunnels created using the anteromedial approach. Clinical Relevance: The use of additional fixation methods, such as post ties or ligament washers and screws, should be considered when using an anterolateral approach for tibial tunnel of posterior cruciate ligament reconstruction.

Original languageEnglish
Pages (from-to)1777-1783
Number of pages7
JournalAmerican Journal of Sports Medicine
Volume37
Issue number9
DOIs
Publication statusPublished - 2009 Dec 2

Fingerprint

Tibia
Transplants
Posterior Cruciate Ligament
Materials Testing
Achilles Tendon
Ligaments
Allografts
Posterior Cruciate Ligament Reconstruction

Keywords

  • Anterolateral approach
  • Killer turn
  • Posterior cruciate ligament reconstruction
  • Transtibial tunnel technique

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

@article{068ca2f24d5940979e717cad999ea3bd,
title = "An anatomical and biomechanical comparison of anteromedial and anterolateral approaches for tibial tunnel of posterior cruciate ligament reconstruction: Evaluation of the widening effect of the anterolateral approach",
abstract = "Background: An anterolateral approach to the tibial tunnel of posterior cruciate ligament reconstruction is used to reduce the sharpness of the graft-tunnel angle, the so-called killer turn effect. However, with the anterolateral approach, the tunnel might be widened into an ovoid shape because of the small angle between the tunnel and the anterolateral cortex. Hypothesis: The fixation strength of the posterior cruciate ligament graft in the tibial tunnel will be weaker in the anterolateral approach compared with the anteromedial approach. Study Design: Controlled laboratory study. Methods: Twenty paired cadaveric tibias were used. Tibial tunnels were made using following approaches: an anteromedial approach for 10 tibias and an anterolateral approach for 10 tibias. The anterior cortex-tunnel angle and the diameter of the tunnel entrance were measured by 2-dimensional computed tomographic scans. After fixation of the Achilles tendon allograft with a biodegradable screw, the maximal strength of the graft at failure was measured using a materials testing machine. Results: The mean cortex-tunnel angle was 47.5° ± 9.3° in the anteromedial approach group and 28.3° ± 7.4° in the anterolateral approach group. The mean long diameter of the tunnels in the anteromedial approach group was 10.6 ± 1.0 mm and in the anterolateral approach group it was 14.0 ± 1.5 mm. These two parameters showed statistically significant differences between the 2 groups (P <.01). The mean maximum load at failure for the anteromedial approach group was 385.4 ± 139.7 N, and for the anterolateral approach group it was 225.1 ± 144.1 N. This difference was statistically significant (P =.021). Conclusion: The anterolateral approach resulted in a tunnel with a wider entrance, a more acute cortex-tunnel angle, and a lower maximal load at failure compared with tunnels created using the anteromedial approach. Clinical Relevance: The use of additional fixation methods, such as post ties or ligament washers and screws, should be considered when using an anterolateral approach for tibial tunnel of posterior cruciate ligament reconstruction.",
keywords = "Anterolateral approach, Killer turn, Posterior cruciate ligament reconstruction, Transtibial tunnel technique",
author = "Ahn, {Jin Hwan} and Bae, {Ji Hoon} and Lee, {Yong Seuk} and Kuiwon Choi and Bae, {Tae Soo} and Wang, {Joon Ho}",
year = "2009",
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T1 - An anatomical and biomechanical comparison of anteromedial and anterolateral approaches for tibial tunnel of posterior cruciate ligament reconstruction

T2 - Evaluation of the widening effect of the anterolateral approach

AU - Ahn, Jin Hwan

AU - Bae, Ji Hoon

AU - Lee, Yong Seuk

AU - Choi, Kuiwon

AU - Bae, Tae Soo

AU - Wang, Joon Ho

PY - 2009/12/2

Y1 - 2009/12/2

N2 - Background: An anterolateral approach to the tibial tunnel of posterior cruciate ligament reconstruction is used to reduce the sharpness of the graft-tunnel angle, the so-called killer turn effect. However, with the anterolateral approach, the tunnel might be widened into an ovoid shape because of the small angle between the tunnel and the anterolateral cortex. Hypothesis: The fixation strength of the posterior cruciate ligament graft in the tibial tunnel will be weaker in the anterolateral approach compared with the anteromedial approach. Study Design: Controlled laboratory study. Methods: Twenty paired cadaveric tibias were used. Tibial tunnels were made using following approaches: an anteromedial approach for 10 tibias and an anterolateral approach for 10 tibias. The anterior cortex-tunnel angle and the diameter of the tunnel entrance were measured by 2-dimensional computed tomographic scans. After fixation of the Achilles tendon allograft with a biodegradable screw, the maximal strength of the graft at failure was measured using a materials testing machine. Results: The mean cortex-tunnel angle was 47.5° ± 9.3° in the anteromedial approach group and 28.3° ± 7.4° in the anterolateral approach group. The mean long diameter of the tunnels in the anteromedial approach group was 10.6 ± 1.0 mm and in the anterolateral approach group it was 14.0 ± 1.5 mm. These two parameters showed statistically significant differences between the 2 groups (P <.01). The mean maximum load at failure for the anteromedial approach group was 385.4 ± 139.7 N, and for the anterolateral approach group it was 225.1 ± 144.1 N. This difference was statistically significant (P =.021). Conclusion: The anterolateral approach resulted in a tunnel with a wider entrance, a more acute cortex-tunnel angle, and a lower maximal load at failure compared with tunnels created using the anteromedial approach. Clinical Relevance: The use of additional fixation methods, such as post ties or ligament washers and screws, should be considered when using an anterolateral approach for tibial tunnel of posterior cruciate ligament reconstruction.

AB - Background: An anterolateral approach to the tibial tunnel of posterior cruciate ligament reconstruction is used to reduce the sharpness of the graft-tunnel angle, the so-called killer turn effect. However, with the anterolateral approach, the tunnel might be widened into an ovoid shape because of the small angle between the tunnel and the anterolateral cortex. Hypothesis: The fixation strength of the posterior cruciate ligament graft in the tibial tunnel will be weaker in the anterolateral approach compared with the anteromedial approach. Study Design: Controlled laboratory study. Methods: Twenty paired cadaveric tibias were used. Tibial tunnels were made using following approaches: an anteromedial approach for 10 tibias and an anterolateral approach for 10 tibias. The anterior cortex-tunnel angle and the diameter of the tunnel entrance were measured by 2-dimensional computed tomographic scans. After fixation of the Achilles tendon allograft with a biodegradable screw, the maximal strength of the graft at failure was measured using a materials testing machine. Results: The mean cortex-tunnel angle was 47.5° ± 9.3° in the anteromedial approach group and 28.3° ± 7.4° in the anterolateral approach group. The mean long diameter of the tunnels in the anteromedial approach group was 10.6 ± 1.0 mm and in the anterolateral approach group it was 14.0 ± 1.5 mm. These two parameters showed statistically significant differences between the 2 groups (P <.01). The mean maximum load at failure for the anteromedial approach group was 385.4 ± 139.7 N, and for the anterolateral approach group it was 225.1 ± 144.1 N. This difference was statistically significant (P =.021). Conclusion: The anterolateral approach resulted in a tunnel with a wider entrance, a more acute cortex-tunnel angle, and a lower maximal load at failure compared with tunnels created using the anteromedial approach. Clinical Relevance: The use of additional fixation methods, such as post ties or ligament washers and screws, should be considered when using an anterolateral approach for tibial tunnel of posterior cruciate ligament reconstruction.

KW - Anterolateral approach

KW - Killer turn

KW - Posterior cruciate ligament reconstruction

KW - Transtibial tunnel technique

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