2025 ISAKOS Biennial Congress ePoster
A Flat Posterior Cruciate Ligament Reconstruction With A Rectangular Femoral Tunnel Restores Native Knee Kinematics - A Biomechanical Robotic Study
Adrian Deichsel, MD, Münster, NRW GERMANY
Florian Gellhaus, MD, Kiel, Schleswig-Holstein GERMANY
Christian Peez, MD, Münster, NRW GERMANY
Michael J. Raschke, MD, Prof., Münster GERMANY
Moritz Martinovic, M.Sc., Münster, NRW GERMANY
Elmar Herbst, MD, PhD, Muenster GERMANY
Mirco Herbort, MD, Prof., Munich GERMANY
Christian Fink, MD, Prof., Innsbruck AUSTRIA
Christoph Kittl, MD, MD(res), Muenster GERMANY
Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, NRW, GERMANY
FDA Status Not Applicable
Summary
A flat PCL reconstruction with rectangular femoral tunnel as well as a double-bundle PCL reconstruction, were able to restore the native knee kinematics in all tested flexion angles.
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Abstract
Background
Rectangular / Flat femoral bone tunnels were previously proposed, as an alternative surgical technique, to provide favorable characteristics for reconstructions of the anterior cruciate ligament. In a previous biomechanical study, a rectangular area inside the femoral footprint of the posterior cruciate ligament (PCL), close to the medial intercondylar ridge was found to be the major restraint to posterior tibial translation.
Purpose
To biomechanically validate a flat PCL reconstruction utilizing rectangular femoral bone tunnels, and to compare it against gold standard single-bundle, and double-bundle techniques.
Methods
A sequential cutting and reconstruction study was performed on eight fresh-frozen human knee specimens, utilizing a six degrees of freedom robotic test setup. Under 200 N of axial compression, the specimens were subjected to 89 N posterior tibial translation (PTT), from 0 to 90° of flexion. After determining the native knee kinematics, the PCL was excised from the knee. Subsequently, a single-bundle PCL reconstruction with a rectangular bone tunnel was performed, utilizing a quadriceps tendon autograft with patellar bone block. In the following, a single-bundle PCL reconstruction without and with femoral interference screw fixation, reconstructing the anterolateral bundle, as well as a double-bundle reconstruction was performed. For all reconstructions, a single tibial bone tunnel was created centrally in the anatomic tibial footprint. Statistical analysis was performed using a mixed linear models, woth posthoc Dunnet-correction. Pairwise comparisons were performed against the native state.
Results
Cutting of the PCL led to a significant increase in PTT from 2.6 mm (in 0°) to 10.7 mm (in 60°), in comparison to the native state. After flat reconstruction of the PCL, no significant difference was found between the native and reconstructed state (P = n.s.). The single-bundle PCL reconstruction without interference screw showed significantly increased PTT in comparison to the native state in 30° (MD 3.3 mm; 95 % CI 1.3 – 5.2 mm; P < 0.002), 60° (MD 4.4 mm; 95 % CI 2.5 – 6.4 mm; P < 0.0001), and 90° of flexion (MD 4.0 mm; 95 % CI 2.1 – 6.0 mm; P < 0.0001). The single-bundle PCL reconstruction with additional interference screw showed significantly increased PTT in comparison to the native state in 30° (MD 1.9 mm; 95 % CI 0.05 - 3.8 mm; P = 0.01). No significant difference was found between the native state and the double-bundle reconstruction (P = n.s.).
Conclusion
A flat PCL reconstruction with rectangular femoral tunnel as well as a double-bundle PCL reconstruction, were able to restore the native knee kinematics in all tested flexion angles, in the PCL-deficient knee. A single-bundle reconstruction with interference screw was not able to restore the native knee kinematics in 30° of flexion with small residual instability. Even though the proposed flat PCL reconstruction is of experimental nature, it provided similar restraint to PTT as the double bundle reconstruction and may be a future option for PCL reconstructions using only a single graft.