Abstract
Placing the tunnels in the anatomic positions is important for successful restoration of knee function after anterior cruciate ligament reconstruction (ACLR). It has been shown that it is difficult to place the tunnels in the anatomic position using the transtibial technique. The purpose of this study was to evaluate the effect of each step of our modified transtibial technique (mTT) on the positioning of the femoral tunnel so as to assess whether the mTT could achieve anatomic placements of the tunnels without tibial tunnel expansion. Ten fresh-frozen cadaveric knees were used. First, the tibial tunnel was created in the center of ACL footprint. Then, a pin was inserted through the tibial tunnel using a femoral guide by four stepwise techniques: transtibial technique, additional anterior drawer force applied to the proximal tibia, another additional varus force applied to the tibia and finally, additional external rotation of the tibia and the femoral guide (mTT). Then, tibial tunnel was re-reamed using mTT with 10mm-diameter reamer. The pin positions in each technique on the femur were evaluated by the quadrant method and shapes of the tibial tunnel apertures were evaluated. Femoral pin positions in the four techniques were 23.6±4.5%, 28.4±3.4%, 30.1±3.8%, 33.2±4.5% in the superior-inferior position, and 23.9±4.3%, 26.2±3.7%, 32.0±4.3%, 36.9±4.8% in the anterior-posterior position, respectively. Pin position shifted to more inferior and posterior position with each step of mTT (all p values comparing superior-inferior and anterior-posterior positions of each step with positions of previous step were 0.008 or less). Using mTT, tibial tunnel aperture was 10.5±0.3mm wide and 12.9±1.1mm long. In conclusion, anatomic placements of femoral tunnels in ACLR without excessive tibial tunnel expansion could be achieved using the mTT.
Highlights
There has been increased focus on the anatomic positioning of the tunnels in anterior cruciate ligament (ACL) reconstruction [1,2,3,4,5,6]
We evaluated tibial tunnel position, which should be in anatomic position for modified transtibial technique (mTT) to be meaningful, and the surgically created tibial tunnel aperture shape to verify the tibial tunnel expansion
The third step of external rotation of the femoral guide and the tibia resulted in the movement of the pin to a more inferior and posterior position (Fig 4, Table 1)
Summary
There has been increased focus on the anatomic positioning of the tunnels in anterior cruciate ligament (ACL) reconstruction [1,2,3,4,5,6]. There were concerns that posterior wall blowout might occur with the transtibial technique when the femoral tunnel was targeted anatomically [9]. It seems quite clear that the modification to the transtibial technique should result in movement of the femoral tunnel to a more posterior and inferior position. To verify the exact positions on the femur and tibia where the tunnel should made, there have been several cadaver studies that reported the anatomic positions of the native ACL footprint [12,13,14,15,16,17,18,19,20,21]. The data reported in these studies should be considered as references when evaluating the tunnel positions by a certain technique to be anatomic or not
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
