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.
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.


OBJECTIVE
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.


METHODS
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 degrees +/- 9.3 degrees in the anteromedial approach group and 28.3 degrees +/- 7.4 degrees 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).


CONCLUSIONS
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.


CONCLUSIONS
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.
Ahn
Jin Hwan
JH
Department of Orthopaedic Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, South Korea.
Bae
Ji Hoon
JH
Lee
Yong Seuk
YS
Choi
Kuiwon
K
Bae
Tae Soo
TS
Wang
Joon Ho
JH
D000125:Achilles Tendon / Q000637:transplantation; D000368:Aged; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D016119:Posterior Cruciate Ligament / Q000293:injuries / Q000601:surgery*; D011183:Postoperative Complications / Q000517:prevention & control; D013977:Tibia / Q000033:anatomy & histology* / Q000601:surgery; D016707:Tissue Fixation / Q000295:instrumentation / Q000379:methods* / Q000592:standards