Outcome of posterior wall blowout in anterior cruciate ligament (ACL) reconstruction via anteromedial portal approach: A retrospective research in 20 patients with 6 years follow-up / 中华创伤杂志(英文版)

PURPOSE@#To evaluate the clinical outcome in patients who received anterior cruciate ligament (ACL) reconstruction via anteromedial portal with or without posterior wall blowout.@*METHODS@#Twenty patients with ruptured ACL, who have received ACL reconstruction via anteromedial portal between Apr 2012 and Oct 2013 were enrolled. According to the conditions of posterior wall, the patients were divided into 2 groups: posterior wall blowout group (10 patients) and posterior wall intact group (10 patients). The median follow up time were 63 (range 19-75) months and 60.5 (range 25-64) months in the 2 groups respectively. The clinical outcome was evaluated by knee joint physical examination, magnetic resonance imaging (MRI), the International Knee Documentation Committee (IKDC) 2000 subjective score, Lysholm score, Tenger score, difference of thigh circumference, KT-2000 and Biodex isokinetic dynamometer system.@*RESULTS@#No significant differences were found in terms of the IKDC score, Lysholm score, Tegner score, Lachman test positive rate or Pivot Shift test positive rate between the two groups. In KT-2000 and Biodex isokinetic dynamometer tests, the difference of muscle strength between affected knees and unaffected knees in posterior wall blowout group was not significant less than that of posterior wall intact group (p > 0.05). In addition, there is no statistical difference between the two groups in signal/noise quotient (SNQ) of the graft (p > 0.05) in post operative MRI.@*CONCLUSION@#Blowout of posterior wall in ACL reconstruction via anteromedial portal does not affect the clinical outcome as long as reliable fixation is taken intraoperatively.

Three-Dimensional Reconstruction Computed Tomography Evaluation of the Tunnel Location and Angle in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction: A Comparison of the Anteromedial Portal and Outside-in Techniques

PURPOSE: The purpose of this study was to compare the geometry and position of the femoral tunnel between the anteromedial portal (AMP) and outside-in (OI) techniques after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction. MATERIALS AND METHODS: We evaluated 82 patients undergoing single-bundle ACL reconstruction with hamstring autografts using either the AMP (n=40) or OI (n=42) technique. The locations of the tunnel apertures were assessed by postoperative 3-dimensional computed tomography imaging. The femoral graft bending angle, femoral tunnel aperture shape, femoral tunnel length, and posterior wall breakage were also measured. RESULTS: The mean femoral tunnel position parallel to the Blumensaat line was more caudally positioned in the AMP group than in the OI group (p=0.025) The mean femoral graft angle in the OI group (99.6°±7.1°) was significantly more acute than that of the AMP group (108.9°±10.2°, p<0.001). The mean height/width ratio of the AMP group (1.21±0.20) was significantly more ellipsoidal than that of the OI group (1.07±0.09, p<0.001). CONCLUSIONS: The mean femoral tunnel position was significantly shallower in the AMP technique than in the OI technique. The OI technique might be more disadvantageous than the AMP technique in terms of the more acute bending angle.

Anatomic Single Bundle Anterior Cruciate Ligament Reconstruction by Low Accessory Anteromedial Portal Technique: An In Vivo 3D CT Study

PURPOSE: Proper femoral tunnel position is important for anatomical reconstruction of the anterior cruciate ligament (ACL). The purpose of this study was to evaluate the positions of femoral and tibial tunnels created using an accessory anteromedial portal technique in single bundle ACL reconstruction. MATERIALS AND METHODS: The femoral tunnel was targeted at the mid-portion of the ACL bundles. We evaluated postoperative computed tomography scans of 32 patients treated by ACL reconstruction using a free-hand low accessory anteromedial portal technique. On the tibial side, the tunnel position was evaluated using Tsukada's method. On the femoral side, the position was evaluated using 1) the quadrant method, 2) Mochizuki's method, 3) Mochizuki's method, and 4) Takahashi's method. Tunnel obliquity was also evaluated. RESULTS: The mean tibial tunnel position was located at 44.6%+/-2.5% anterior from the anterior margin and 48.0%+/-3.0% in medial from the medial margin. The mean femoral tunnel position was located at the center between the anteromedial and posterolateral bundles: Quadrant method, 26.7%+/-2.7%/30.0%+/-2.9%; Watanabe's method, 37.7%+/-2.5%/26.6%+/-2.2%; Mochizuki's method, 38.7%+/-2.7%; Takahashi's method, 21.8%+/-2.2%. The mean femoral tunnel obliquity was 57.7degrees+/-6.2degrees in the sagittal plane and 49.9degrees+/-5.6degrees in the coronal plane. CONCLUSIONS: In anatomic single bundle ACL reconstruction, the low anteromedial portal technique can restore accurate position of the native footprint. Accurate femoral tunnel position facilitates recovery of stability and decreases graft failure rate.

Effect of Anteromedial Portal Entrance Drilling Angle during Anterior Cruciate Ligament Reconstruction: A Three-Dimensional Computer Simulation

PURPOSE: The object of this study was to evaluate entrance angle effects on femoral tunnel length and cartilage damage during anteromedial portal drilling using three-dimensional computer simulation. MATERIALS AND METHODS: Data was obtained from an anatomic study performed using 16 cadaveric knees. The anterior cruciate ligament femoral insertion was dissected and the knees were scanned by computer tomography. Tunnels with different of three-dimensional entrance angles were identified using a computer simulation. The effects of different entrance angles on the femoral tunnel length and medial femoral cartilage damage were evaluated. Specifically, tunnel length and distance from the medial femoral condyle to a virtual cylinder of the femoral tunnel were measured. RESULTS: In tunnels drilled at a coronal angle of 45degrees, an axial angle of 45degrees, and a sagittal angle of 45degrees, the mean femoral tunnel length was 39.5+/-3.7 mm and the distance between the virtual cylinder of the femoral tunnel and the medial femoral condyle was 9.4+/-2.6 mm. The tunnel length at a coronal angle of 30degrees, an axial angle of 60degrees, and a sagittal angle of 45degrees, was 34.0+/-2.9 mm and the distance between the virtual cylinder of the tunnel and the medial femoral condyle was 0.7+/-1.3 mm, which was significantly shorter than the standard angle (p<0.001). CONCLUSION: Extremely low and high entrance angles in both of axial plane and coronal plane produced inappropriate tunnel angles, lengths and higher incidence of cartilage damage. We recommend that angles in proximity to standard angles be chosen during femoral tunnel drilling through the anteromedial portal.

The risk of chondral injury during the Rigidfix femoral fixation via the anteromedial portal to reconstruct the anterior cruciate ligament / 中华创伤骨科杂志

Objective To evaluate the risk of chondral injury during anterior cruciate ligament (ACL) reconstruction using a double cross-pin femoral fixation device via the anteromedial portal in Chinese cadavers. Methods Nine specimens of the knee (6 left ones and 3 right ones) were taken from 5 male and 4 female conservative cadavers of Chinese adult. The average age of the cadavers were 34.8 (26 to 45)years old. Femoral tunnel drilling and cross-pin guide insertion were performed using the Rigidfix Cross Pin device through the anteromedial portal. The ACL reconstructions were simulated at 3 entrance points of the cross-pin (0°, 45° and 90° relative to the horizontal plane) . The risks of chondral injury were statistically analyzed when the cross-pin entrance point was at the 3 different positions relative to the femoral chondral surface. Results The incidence of chondral injury was 100% when the Rigidfix cross-pin guide was at 90° relative to the horizontal plane. When the Rigidfix cross-pin guide was at 45° and 0° the incidences of chondral injury were 66. 7% and 22. 2% respectively. Conclusion Since there is always a risk of chondral injury when the Rigidfix cross-pin device is used to reconstruct ACL via the anteromedial portal, the anteromedial portal is not recommended for the ACL reconstruction using Rigidfix femoral fixation.

Single Bundle Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction is generally accepted as the most reliable method of re-establishing knee kinematics so as to prevent various symptoms related to the instability and subsequent injuries to the knee. Double bundle ACL reconstruction has emerged as a potential solution for single bundle reconstruction, as the latter can restore anteroposterior stability, but it had limitations for improving the rotational stability. However, double bundle reconstruction is a more complex surgical procedure and it remain unclear whether double bundle reconstruction has better results than single bundle reconstruction on long term follow-up. Recent studies have demonstrated that a femoral tunnel could be created independently of the tibial tunnel and in a more anatomic position by using the anteromedial portal technique, so that that there is better restoration of the rotational stability as well as anterior stability than that with performing the transtibial technique.