A comprehensive study published in Scientific Reports compared two surgical techniques to address medial meniscus posterior root tears (MMPRT), aiming to optimize treatment for this common knee injury. By utilizing finite element analysis (FEA), the researchers examined the biomechanical effects of isolated high tibial osteotomy (HTO) versus the combination of medial meniscus posterior root (MMPR) repair with either medial open wedge high tibial osteotomy (MOWHTO) or lateral closed wedge high tibial osteotomy (LCWHTO).
Results from this analysis revealed significant differences in stress distribution and overall mechanical performance in the knee joint. Specifically, it was found that the combination of MMPR repair with LCWHTO yielded superior outcomes, including a reduction in maximum contact stress by 5.4–11.4% and an increase in contact area by 29.5–41.0% in the medial compartment, when compared to the isolated HTO approaches.
The study clarifies that MMPRTs comprise a notable percentage of all meniscal injuries, estimated between 10.1% and 27.8%. Given this high frequency, developing effective surgical strategies is critical. Within the scope of the research, it was also noted that MOWHTO typically leads to an increased posterior tibial slope (PTS), while LCWHTO tends to decrease it, which plays a crucial role in the distribution of mechanical stress across the knee joint.
By manipulating the PTS through these osteotomy techniques, researchers were able to alter the mechanical environment of the knee. The findings indicated that following LCWHTO, the PTS decreased by 3.1° and 1.0° at differing angles compared to the native knee model, leading to less stress on the medial meniscus. In contrast, the PTS increased significantly by the same angles under the MOWHTO model, underscoring the challenges associated with this technique.
Investigation into stress profiles during loading conditions demonstrated that the maximum von Mises stress (VMS) and shear stress levels in the MMPR were notably lower with LCWHTO compared to isolated HTO. For example, in variant models under LCWHTO, the maximum VMS and shear stress reduced by 3.8-33.1% and 3.4-26.5%, respectively. Conversely, under MOWHTO conditions, these stress metrics inflated significantly, with increases ranging from 10.9-46.5% for VMS, suggesting a less favorable biomechanical outcome.
These critical findings highlight the enhanced biomechanical advantages of combining MMPR repairs with osteotomies, particularly LCWHTO, as it appears to facilitate a more conducive healing environment for the meniscus as well as preserving cartilage integrity in the medial knee compartment.
Although the study's results are compelling, they hinge upon data obtained from a single healthy volunteer. As such, further validation across diverse demographic groups is essential for generalizability. Moreover, while finite element methods provide valuable insights into joint dynamics, they may not encompass the full complexity of real-world biomechanics, especially given individual anatomical variations.
Overall, the study underlines the need for careful consideration of surgical methods when treating meniscal injuries. As the authors noted, "These findings support the hypothesis of the current study, highlighting the importance of adjustment of the PTS for obtaining better clinical outcomes following surgery of the MMPRT." The implications for clinical practice could mean a shift towards employing LCWHTO in combination with MMPR repairs to enhance patient recovery and minimize the risk of osteoarthritis progression, marking a significant step forward in orthopedic surgery.
