Biomechanical Evaluation of an All-Inside Posterior Medial Meniscal Root Repair Technique via Suture Fixation to the Posterior Cruciate Ligament

Purpose: The purpose of this study was to evaluate the tibiofemoral contact mechanics of an all-inside posterior medial meniscal root repair technique via suture fixation to the posterior cruciate ligament (PCL), and to compare with that of the intact knee and the knee with a root tear.

Methods: Tibiofemoral contact mechanics were recorded in 8 human cadaveric knee specimens using pressure sensors. Each knee underwent 3 testing conditions related to the posterior medial meniscal root: (1) intact knee; (2) root tear; and (3) all-inside repair via suture fixation to the PCL. Knees were loaded with a 1000-N axial compressive force at 4 knee flexion angles (0°, 30°, 60°, 90°). Calculations were performed for contact area, mean contact pressure, and peak contact pressure. A generalized linear model with a Tukey Adjusted Least Square Means (LSM) test was used to determine differences between testing conditions.

Results: Across all knee flexion angles, there was an overall mean 26.3% reduction in contact area with root tear (211.34 mm2 vs. intact 286.64 mm2, p=0.0002), and a 31.6% increase from root tear to repair (277.61 mm2, p=0.0297). Across all knee flexion angles, there was an overall mean 24.3% increase in contact pressure with root tear (1849.12 N/mm2 vs. intact 1487.52 N/mm2, p<0.0001), and a 31.1% decrease from root tear to repair (1410.7 N/mm2, p=0.0037). Across all knee flexion angles, there was an overall mean 10.6% increase in peak contact pressure with root tear (4083.55 N/mm2 vs. intact 3693.68 N/mm2, p<0.0001), and a 12.4% decrease from root tear to repair (3632.13 N/mm2, p=0.531).

Conclusion: In most testing conditions and with overall averaging across knee flexion angles, the all-inside posterior medial meniscal root repair with suture fixation to the adjacent PCL fibers restored contact area, contact pressures, and peak contact pressures to that of the intact knee. This may be a future potential technique to limit complications associated with the traditional transtibial pull-out method of repair.