2025 ISAKOS Biennial Congress Paper
Anterior Closed Wedge High Tibial Osteotomy for Tibial Slope Correction: Biomechanical Analysis of Common Techniques
Andrzej Jasina, Dr. med., Rostock GERMANY
Pia Metje, Cand. med. , Rostock GERMANY
Jan-Oliver Sass, M.Sc., Rostock GERMANY
Jessica Hembus, M.Sc., Rostock GERMANY
Parisa Pourostad, M.Sc., Rostock GERMANY
Christoph Lutter, MD, Rostock, - GERMANY
Felix Ferner, Dr., Lichtenfels GERMANY
University Medical Center of Rostock, Rostock, GERMANY
FDA Status Cleared
Summary
Current techniques of Anterior Closed Wedge - High Tibial Osteotomies (ACW-HTO) show similar resistance to tensile load and could thus be considered stable, but trans-tuberosity ACW-HTO with subsequent tibial tubercle “bioplating” showed increased micromovement in our biomechanical setup, which should be considered when choosing the osteosynthesis technique for ACW-HTO.
Abstract
Background
To reduce ACL reconstruction failures, recent research has focused on identifying potential risk factors such as the posterior tibial slope (PTS). Increased PTS results in greater anterior tibial translation and thus increases the likelihood of ACL reconstruction failure. The causal therapy for pathologically elevated PTS is the "Anterior Closed Wedge - High Tibial Osteotomy" (ACW-HTO). Current techniques differ, e.g., in terms of the osteosynthesis techniques used. There are currently no studies comparing these osteosynthesis techniques in terms of biomechanical stabilization of the osteotomy under relevant loading situations.
Methods
18 fresh-frozen human cadaver knees were used in this study, divided into two intervention groups and one control group. ACW-HTO for PTS correction was performed in both intervention groups using two common techniques: a trans-tuberositary technique using the tibial tubercle as a “bioplate” to stabilize the osteotomy and an infra-tuberosity osteotomy stabilized with an angle-stable plate (“NewClip” Active motion Deflexion Osteotomie Plate). An electrodynamic uniaxial testing machine (LTM 5, Zwick Roell GmbH & Co KG, Ulm Germany) was used to perform the biomechanical tests. Tensile load was applied to the quadriceps tendon at an flexion angle of 45°. After preloading, 1,000 load cycles between 50 N and 200 N were performed at 1 Hz. The specimens were then loaded at 10 mm/s until failure. The relative change in distance of the osteotomy gaps (micromovement) after 200 and 800 cycles were analyzed using a 3D optical measurement system.
Results
After 200 cycles, no significant difference in micromovement at the osteotomy was found between the two intervention groups. However, micromovement was significantly increased in the “bioplate” group after 800 cycles (0.055±0.017 mm vs. 0.069±0.035 mm, p=0.0253). The mean force measured at the time of osteosynthesis failure was 77.12 N higher in the ‘angle-stable plate’ group (643.89±190.84 N) than in the “bioplate” group (566.77±110.99 N), but this difference did not reach statistical significance. In all knees of the intervention groups, failure of the osteosynthesis led to termination of the test. In the control group (1386.80±215.41 N) suture disruption was the cause in all cases.
Conclusions
Both intervention groups showed similar resistance to tensile load and both osteotomy techniques could thus be considered stable. However, trans-tuberosity ACW-HTO with tibial tubercle detachment and subsequent “Bioplating” showed increased micromovement of the osteosynthesis gap compared to osteosynthesis with an angle-stable plate in our biomechanical setup. This should be considered when choosing the osteosynthesis technique for ACW-HTO. Further, postoperative treatment strategies must be carefully chosen as considerable tensile forces on the quadriceps and patellar tendons are described in literature that vary during gait depending on the knee flexion angles. Further biomechanical analyses on stability during gait are therefore required.