Biomechanical evaluation of meniscal root repair: a porcine study

Meniscal root repair is commonly practised using transtibial pull-out sutures. The purpose of the study was to investigate whether these are effective in restoring contact of the root to its footprint and a normal loading pattern of the cartilage under restricted loading conditions as used post-operatively.

First, a transtibial pull-out suture was simulated using porcine menisci (n = 10). It was repetitively loaded (100×; 1-10 N) and the elongation of the suture determined. In the second part of the study, porcine knees (n = 8) were subjected to repetitive low-level femoro-tibial loads (50 cycles; 100 N). A displacement sensor measured the deformation of the cartilage in the area of femoro-tibial contact. The residual deformation of the cartilage, which results from its viscoelastic behaviour, was determined as a measure of the local stress. Three scenarios were investigated: meniscal root intact, detached, and repaired.

Repetitive loading caused a median suture elongation of 3.8 mm. Residual deformation of the cartilage was increased (p = 0.047) with the root detached. Root repair could not restore it to normal (n.s.).

In this model, meniscus root repair was not effective in restoring the normal loading pattern of the cartilage because cyclic loading caused an elongation of the repair.

In practice, this effect might impair the healing of repaired meniscal roots to the tibial bone.