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

Purpose: 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 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 mm vs intact 286.64 mm, P = .0002), and a 31.6% increase from root tear to repair (277.61 mm, P = .0297). Across all knee flexion angles, there was an overall mean 24.3% increase in contact pressure with root tear (1849.12 N/mm vs. intact 1487.52 N/mm, P < .0001), and a 31.1% decrease from root tear to repair (1410.7 N/mm, P = .0037). Across all knee flexion angles, there was an overall mean 10.6% increase in peak contact pressure with root tear (4083.55 N/mm vs. intact 3693.68 N/mm, P < .0001), and a 12.4% decrease from root tear to repair (3632.13 N/mm, P = .531).

Conclusions: 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 (from 26.3% reduction with root tear to 31.6% increase with repair), contact pressures (from 24.3% increase with root tear to 31.1% decrease with repair), and peak contact pressures (from 10.6% increase with root tear to 12.4% decrease with repair) 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.

Clinical Relevance: This technique may provide a posterior medial meniscal root repair construct that restores most tibiofemoral contact mechanics and offers theoretical benefits of technical ease and potential for an acceptable, less "anatomic" repair location.