Title:
The lateral tibial tunnel in revision anterior cruciate ligament surgery: a biomechanical study of a new technique.

Abstract:
To evaluate the cortical entry point and the length of a revision lateral tibial tunnel (LTT) in a human cadaveric study and to investigate knee stability after a revision anterior cruciate ligament (ACL) reconstruction with an LTT.
Ten human cadaveric knee specimens were used to perform a preliminary investigation. Twenty-two human proximal tibias were used to compare the length of a revision LTT with a classical medial tibial tunnel (MTT). Another 5 human cadaveric knees were used to investigate knee stability after a revision LTT and to compare it with a primary ACL repair with an MTT performed in the same knees. Stability was evaluated with computer navigation.
An LTT is statistically significantly longer (45.0 mm) than an MTT (35.2 mm) (P < .001). There was no evidence of a length difference between the intact bone tube length of a revision LTT (36.5 mm) and an MTT. For nearly all measurements, the difference between the ACL repair with an MTT and the revision surgery with an LTT was not only nonsignificant but also small in magnitude. Only for internal rotation at 30° of knee flexion and for internal rotation in extension was a significant difference detected (P = .029 and P = .044, respectively).
An LTT can easily be drilled and provides a bony tunnel that is statistically significantly longer than an MTT. A revision LTT has an intact bone tube as long as that of a primary MTT. Similar stability is obtained after revision ACL surgery with an LTT compared with a primary ACL repair with a standard MTT.
LTT placement is a new technique for ACL revision surgery that can help to overcome problems related to tunnel enlargement in the distal part of the tibial tunnel.