Safety of the application of Rigidfix cross-pin system via different tibial tunnels for tibial fixation during anterior cruciate ligament reconstruction

Research progress on preparation of lateral femoral tunnel and graft fixation in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) injury is one of the most common types of sports injuries. People's need to participate in sports and desire for a high quality of life promotes the continuous development of ACL reconstruction technology. Arthroscopic ACL reconstruction has been recognized as an effective method for the treatment of ACL injuries. This review analyses and summarizes the advantages and limitations of each surgical procedure for arthroscopic ACL reconstruction reported in the relevant literature so as to promote the future development of more relevant techniques.

[Research progress of tibial-graft fixation methods on anterior cruciate ligament reconstruction]

Objective

To review the studies about the tibial-graft fixation methods on anterior cruciate ligament (ACL) reconstruction, in order to provide clinical reference.

Methods

The literature about the tibial-graft fixation methods on ACL reconstruction at home and abroad was extensively reviewed, and the factors that affect the selection of fixation methods were summarized.

Results

The knee flexion angle, graft tension, and graft fixation device are mainly considered when the tibial-graft was fixed on ACL reconstruction. At present, the graft is mainly fixed at 0°/30° of knee flexion. The study shows that the knee joint is more stable after fixed at 30°, while the incidence of knee extension limitation decrease after fixed at 0°. In terms of graft tension, a good effectiveness can be obtained when the tension level is close to 90 N or the knee flexion is 30° to recover the affected knee over-restrained 2 mm relative to the healthy knee. In terms of the graft device, the interference screw is still the most commonly used method of tibial-graft fixation, with the development of all-inside ACL reconstruction in recent years, the cortical button fixation may become the mainstream.

Conclusion

Arthroscopic reconstruction is the main treatment of ACL rupture at present. However, there is no optimal fixation method for the tibial-graft, the advantages and disadvantages of each fixation methods need to be further studied.

Safe femoral tunnel drilling angles avoid injury to the medial and posteromedial femoral anatomic structures during single-bundle posterior cruciate ligament reconstruction with the inside-out technique

PURPOSE

To investigate the relationship between the medial and posteromedial femoral anatomic structures and the femoral tunnel exit produced by different tunnel orientations when creating the femoral tunnel for posterior cruciate ligament reconstruction (PCLR) using the inside-out (IO) technique and to estimate safe tunnel orientations to minimize the risk of iatrogenic injury to these structures.

METHODS

Eleven cadaveric knees were used. The medial and posteromedial aspects of each knee joint were dissected to reveal the "safe zone," which is a bony area that avoids the distribution or attachment of at-risk structures (MCL, PMC structures, and articular cartilage), while remaining 10 mm away from the articular cartilage. The hypothesis of this study was that by creating the femoral tunnel at specific angles using the IO technique, the tunnel outlet would be as close to the safe zone as possible, protecting the at-risk structures from damage. Femoral tunnels were drilled at 20 different angle combinations on each specimen: 0°, 15°, 30°, 45°, and 60° relative to a line parallel to the transepicondylar axis in the axial plane, as well as 15°, 30°, 45°, and 60° relative to a line parallel to the femoral axis in the coronal plane. The positional relationship between each tunnel exit and the safe zone was recorded, and the shortest distance between the exit center and the safe zone boundary was measured.

RESULTS

The risk of iatrogenic injury differed depending on the drilling orientation (χ² = 168.880, P < 0.001). Femoral drilling angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/coronal) were considered relatively safer than other orientations (P < 0.05). The shortest distance between the tunnel exit and the safe zone boundary was negatively correlated with the angle in the axial plane (P < 0.001, r = - 0.810).

CONCLUSIONS

When creating the IO femoral tunnel for single-bundle PCL reconstruction, angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/oblique coronal) could be utilized to prevent at-risk structures from being damaged. The drilling angles and the safe zone can be employed to optimize the femoral tunnel in PCLR.

BIOMECHANICAL EVALUATION OF AN INVERTED FIXATION FOR ACL RECONSTRUCTION WITH NONMETALLIC HARDWARE AND TIBIAL SUBCORTICAL SUPPORT TO INCREASE STRENGTH AT THE TIBIAL SITE

In this paper, we evaluate the initial biomechanical properties of an anterior cruciate ligament (ACL) reconstruction technique that inverts the anatomical location of the commonly used hardware and relies the tibial fixation on the subcortical bone to increase tibial site strength. Four 7-specimen groups were tested in a porcine model: for the control ACL reconstruction technique, the femur with a cross-pin fixation supported in the trabecular bone and the tibia with a biodegradable interference screw (BIS); for the new proposed technique, the femur with a BIS and the tibia with a cross-pin fixation leaned on the tibial subcortical bone. The specimens were subjected to cyclic and load-to-failure tests to compute their biomechanical performance. At the tibia, the cross-pin fixation revealed higher resistance than the BIS ([Formula: see text] for ultimate load and [Formula: see text] = 0.006 for yield load), additionally cyclic and total displacement at representative loads showed extremely high values with BIS fixation (in two specimens greater than 9[Formula: see text]mm for 250 N and greater than 10[Formula: see text]mm for 450[Formula: see text]N). At the femur, no differences between fixations were observed. The inverted ACL reconstruction improves resistance at the tibial site with respect to the control technique, with similar resistance at the femoral site and no differences in total displacement at representative loads. It offers a useful and robust solution when greater tibial resistance is required.

Outcomes of retro-drilled all-inside tibial tunnel vs complete tibial tunnel techniques in anterior cruciate ligament reconstruction-a comparative study

PURPOSE

The all-inside tibial tunnel preparation technique of arthroscopic anterior cruciate ligament (ACL) reconstruction differs from traditional complete tibial tunnel technique in using closed tibial sockets, dual-cortical suspensory graft-fixation, quadrupled semitendinosus tendon graft and lesser bone removal. The study aims to find out if all-inside technique differs from complete tibial tunnel technique of single bundle ACL reconstruction in terms of graft dimensions, functional and clinical outcomes.

METHODS

A prospective comparative study was conducted including 80 patients with isolated ACL tears, divided into 2 groups of 40 patients each without any randomization. The two techniques differed in tibial tunnel preparation. Group 1 underwent ACL reconstruction with a complete tibial tunnel drilled from the anteromedial tibial cortex and group 2 underwent all-inside tibial socket preparation. Duration of the surgery, perioperative and midterm complications were noted. All patients had 24 month follow-up. Functional outcome scores (Tegner-Lysholm knee scoring scale and IKDC score) were assessed preoperatively and postoperatively at 6 months and 24 months. Hamstring and quadriceps muscle strength was assessed preoperatively and postoperatively at 6 months, 9 months and 24 months. Visual analogue score (VAS) for knee pain was assessed preoperatively and postoperatively at day 2, 2 weeks, 6 weeks, 6 months and 24 months.

RESULTS

Quadrupled semitendinosus tendon graft was significantly thicker than doubled semitendinosus and gracilis tendons graft (8.17 ± 0.58 vs 8.71 ± 0.4, p < 0.0001). The VAS score for knee pain at 2 and 6 weeks were lower in group 2 (5.75 ± 0.6 and 1.78 ± 1.0) as compared to group 1 (6.50 ± 0.5 and 2.5 ± 0.8) and the difference was statistically significant (P = 0.0007 and p = 0.002 respectively). There were no statistically significant differences in functional outcome scores and quadriceps muscle strength between the two groups. However, there were significant difference in hamstring power in two groups.

CONCLUSION

The all-inside technique has the advantages of using a single tendon graft, lesser early postoperative pain with similar clinical and functional outcomes compared to the complete tibial tunnel technique. Level of Evidence IIProspective comparative study.