Biomechanical evaluation of meniscal root repair: a porcine study

Abstract

Purpose: 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.

Methods: 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.

Results: 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.).

Conclusions: 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.

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