Different effects of the lateral meniscus complete radial tear on the load distribution and transmission functions depending on the tear site

Abstract Purpose To compare the effect of the lateral meniscus (LM) complete radial tear at different tear sites on the load distribution and transmission functions. Methods A compressive load of 300 N was applied to the intact porcine knees ( n = 30) at 15°, 30°, 60°, 90°, and 120° of flexion. The LM complete radial tears were created at the middle portion (group M), the posterior portion (group P), or the posterior root (group R) ( n = 10, each group), and the same loading procedure was followed. Finally, the recorded three‐dimensional paths were reproduced on the LM‐removed knees. The peak contact pressure (contact area) in the lateral compartment and the calculated in situ force of the LM under the principle of superposition were compared among the four groups (intact, group M, group P, and group R). Results At all the flexion angles, the peak contact pressure (contact area) was significantly higher (lower) after creating the LM complete radial tear as compared to that in the intact state ( p < 0.01). At 120° of flexion, group R represented the highest peak contact pressure (lowest contact area), followed by group P and group M ( p < 0.05). The results of the in situ force carried by the LM were similar to those of the tibiofemoral contact mechanics. Conclusion The detrimental effect of the LM complete radial tear on the load distribution and transmission functions was greatest in the posterior root tear, followed by the posterior portion tear and the middle portion tear in the deep‐flexed position. Complete radial tars of the meniscus, especially at the posterior root, should be repaired to restore the biomechanical function.