Transtibial versus independent femoral tunnel drilling techniques for anterior cruciate ligament reconstruction: evaluation of femoral aperture positioning

Surgical Robots Improve Tunnel Angle and Graft Bending Angle in Anatomic ACL Reconstruction: A Multicenter Study

The anatomic characteristics of the graft and tunnel, i.e., the tunnel position, angle, length, and the graft bending angle, influence knee joint stability and postoperative functional recovery. The purpose of this study was to evaluate the tunnel position, length and angle, as well as graft bending angle after ACL reconstruction assisted by a surgical robot. A total of 70 patients were randomized into two groups: the surgical robot group (robot group, n = 35) and the traditional handheld locator group (control group, n = 35). Postoperative computed tomography (CT) was employed to assess the positions and lengths of the tunnels, as well as the tunnel angle and the graft bending angle. Additionally, the posterior wall distance was measured by determining the minimum vertical distance from the long axis of the tunnel to the posterior wall region. There were no significant differences between the two groups in the mean position or length of the femoral and tibial tunnel (p > 0.05). However, the femoral tunnel angle was significantly larger in the robot group compared to the handheld locator group (p = 0.012). The graft bending angle was significantly less acute in the robot group than in the control group (p = 0.008). Additionally, the posterior wall distance was significantly greater in the robot group compared to the control group (p < 0.001). The results suggest that surgical robot-assisted ACL reconstruction enhances safety in the inclination of the tunnel and graft, helping to avoid potential biomechanical issues such as the wiper effect and the bungee effect, which may lead to tunnel widening and surgical failure.

Limited accuracy of transtibial aiming for anatomical femoral tunnel positioning in ACL reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) rupture is a common knee injury, and with advancements in knee arthroscopy, ACL reconstruction has become common. Techniques like single-double bundle and femoral tunnel drilling via transtibial or anteromedial portal approaches are available. This study evaluates the accuracy of femoral tunnel placement via these approaches in single-bundle ACL reconstruction.

MATERIALS AND METHODS

Forty-three ACL reconstructions using hamstring grafts were analyzed. Initially, femoral tunnels were drilled via the anteromedial portal from 09:30 to 10:00 (14:00 to 14:30 for left knees). Tibial tunnels (mean anteroposterior angle: 63.5°, sagittal: 64.2°) were then created with the same diameter, accompanied by radiological documentation. A femoral aiming device was used to place a K-wire at the center of the femoral tunnel, recorded photographically. Tunnel diameters included 7 mm (20 cases), 7.5 mm (11 cases), 8 mm (7 cases), 8.5 mm (3 cases), and 9 mm (1 case). Two observers evaluated all radiological and photographic data, focusing on the deviation of the transtibial K-wire from the femoral tunnel center.

RESULTS

Of 38 evaluated cases, the transtibial K-wire was within the femoral tunnel in 11 cases (28.9%) - 7 cases with 7 mm, 2 cases each with 7.5 mm and 8 mm diameters. In 23 cases (60.5%), the K-wire was at the perimeter or outside the femoral tunnel - 11 cases with 7 mm, 8 with 7.5 mm, 4 with 8 mm, 3 with 8.5 mm, and 1 with 9 mm diameters.

CONCLUSION

Transtibial aiming for anatomical femoral tunnel positioning is challenging. No significant correlation was found between the transtibial deviation and the tibial tunnel diameter.

Comparison of femoral tunnel position and knee function in anterior cruciate ligament reconstruction: a retrospective cohort study using measuring-fluoroscopy method versus bony marker method

BACKGROUND

Previous studies have shown that surgical technique errors especially the wrong bone tunnel position are the primary reason for the failure of anterior cruciate ligament (ACL) reconstruction. In this study, we aimed to compare the femoral tunnel position and impact on knee function during the ACL reconstruction using measuring combined with fluoroscopy method and bony marker method for femoral tunnel localization.

METHODS

A retrospective cohort study of patients undergoing ACL reconstruction using the bony marker method or measuring combined with fluoroscopy for femoral tunnel localization was conducted between January 2015 and January 2020. A second arthroscopic exploration was performed more than 1 year after surgery. Data regarding patient demographics, the femoral tunnel position, results of the Lysholm score, the International Knee Documentation Committee (IKDC) score, KT-1000 side-to-side difference, pivot shift grade, and Lachman grade of the knee were collected.

RESULTS

A total of 119 patients were included in the final cohort. Of these, 42 cases were in the traditional method group, and 77 cases were in the measuring method group. The good tunnel position rate was 26.2% in the traditional method group and 81.8% in the measuring method group (p < 0.001). At the final follow-up, the Lysholm and IKDC scores were significantly greater in the measuring method group than the traditional method group (IKDC: 84.9 ± 8.4 vs. 79.6 ± 6.4, p = 0.0005; Lysholm: 88.8 ± 6.4 vs. 81.6 ± 6.4, p < 0.001). Lachman and pivot shift grades were significantly greater in the measuring method group (p = 0.01, p = 0008). The results of KT-1000 side-to-side differences were significantly better in the measuring method group compared with those in the traditional method group (p < 0.001).

CONCLUSIONS

The combination of the measuring method and intraoperative fluoroscopy resulted in a concentrated tunnel position on the femoral side, a high rate of functional success, improved knee stability, and a low risk of tunnel deviation. This approach is particularly suitable for surgeons new to ACL reconstructive surgery.

Lateral femoral tunnel preparation and graft fixation for anterior cruciate ligament reconstruction-A discussion

This article provides a discussion and commentary around the recent advances in arthroscopic anterior cruciate ligament reconstruction (ACLR), with a focus on the aspects of lateral femoral tunnel preparation and graft fixation techniques. The paper explores and comments on a recently published review by Dai et al, titled "Research progress on preparation of lateral femoral tunnel and graft fixation in ACLR", while providing insight into its relevance within the field of ACLR, and recommendations for future research.

Robot-assisted anterior cruciate ligament reconstruction based on three-dimensional images

Background Tunnel placement is a key step in anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to evaluate the accuracy of bone tunnel drilling in arthroscopic ACL reconstruction assisted by a three-dimensional (3D) image-based robot system. Methods Robot-assisted ACL reconstruction was performed on twelve freshly frozen knee specimens. During the operation, three-dimensional images were used for ACL bone tunnel planning, and the robotic arm was used for navigation and drilling. Twelve patients who underwent traditional arthroscopic ACL reconstruction were included. 3D computed tomography was used to measure the actual position of the ACL bone tunnel and to evaluate the accuracy of the robotic and traditional ACL bone tunnel. Results On the femoral side, the positions of robotic and traditional surgery tunnels were 29.3 ± 1.4% and 32.1 ± 3.9% in the deep-to-shallow direction of the lateral femoral condyle (p = 0.032), and 34.6 ± 1.2% and 21.2 ± 9.4% in the high-to-low direction (p < 0.001), respectively. On the tibial side, the positions of the robotic and traditional surgical tunnels were located at 48.4 ± 0.9% and 45.8 ± 2.8% of the medial-to-lateral diameter of the tibial plateau (p = 0.008), 38.1 ± 0.8% and 34.6 ± 6.0% of the anterior-to-posterior diameter (p = 0.071), respectively. Conclusions In this study, ACL reconstruction was completed with the assistance of a robot arm and 3D images, and the robot was able to drill the bone tunnel more accurately than the traditional arthroscopic ACL reconstruction.

Modification of Outside-In Technique In Preparing Femoral Tunnel During Anterior Cruciate Ligament Reconstruction-"PL-Portal Outside-In Technique"

We propose modifying the outside-in technique by adopting a posterolateral (PL) portal as the working portal to introduce the anterior cruciate ligament reconstruction (ACLR) aiming guide while keeping the anteromedial portal as the viewing portal, the "PL-portal outside-in technique." This modification facilitates the preparation of an anatomical femoral tunnel, even when preserving a "big" ACL remnant or in small joint scenarios, such as pediatric ACLR. There is a minimal learning curve in adopting this technique because a standard 30° arthroscope is used, and the viewing portal is anterior.

The proximal posterior cartilage of the lateral femoral condyle can be used as a reference for positioning the femoral tunnel in ACL reconstruction

PURPOSE

To describe the femoral insertion of the ACL using the posterior proximal cartilage of the lateral femoral condyle as the anatomical reference.

METHODS

Twenty knees were dissected. The X-axis (deep-shallow) and Y-axis (high-low) were determined using the femoral diaphysis and the proximal cartilage of the lateral femoral condyle (point C) as a reference, which were easily identified by direct visualization through the anteromedial portal. The distances to the center of the anteromedial and posterolateral bands and to the center of the ACL were measured.

RESULTS

The mean distances were 7.2 mm (SD: 0.7) between the center of the anteromedial bundle and the Y-axis (AM-Y), 9 mm (SD: 1.1) between the center of the ACL and the Y-axis (M-Y), and 12.7 mm (SD: 0.9) between the center of the posterolateral bundle and the Y-axis (PL-Y). Regarding the distance (from point C to the distal cartilage along the X-axis), the center of the anteromedial bundle (AM) was 35% (SD: 4.9%), the center of the posterolateral bundle was 62% (SD: 3.7%), and the center of the ACL (M) was 44% (SD: 7%) of the CD distance on average.

CONCLUSION

Given the similarity among the specimens in terms of the height of the ACL on the Y-axis in relation to the proximal posterior cartilage of the femoral lateral condyle (point C), this point can be used as an arthroscopic intraoperative parameter to define the position of the femoral tunnel in ACL reconstruction for single- or double-bundle techniques.