Transtibial Centralization Better Restores Meniscal Extrusion and Contact Mechanics Compared With Knotless Anchor Centralization for Medial Meniscal Posterior Root Tears: An In Vitro Biomechanical Study Using a Porcine Model.

Abstract

To investigate the tibiofemoral contact mechanics and extent of medial meniscal extrusion (MME) between an isolated anatomic transtibial pull-through root repair (ATPR) and an ATPR combined with either transtibial or knotless anchor centralization in a porcine medial meniscal posterior root tear (MMPRT) model. Porcine knee joints (N = 12) were used to test 5 meniscal conditions: (1) intact, (2) MMPRT, (3) ATPR, (4) ATPR with transtibial centralization (TTC), and (5) ATPR with 2 knotless anchor-based centralization (2AC). Contact area and peak contact pressure on the medial meniscus, as well as extrusion, were evaluated at 30°, 45°, 60°, and 90° of knee flexion under a 200-N compressive force. MME was significantly less after ATPR-TTC than after ATPR or ATPR-2AC at 60° (2.68 mm vs 4.39 mm vs 4.09 mm, P < .001) and 90° (2.99 mm vs 4.75 mm vs 4.36 mm, P < .001). Contact area was significantly greater with ATPR-TTC than with ATPR-2AC at 60° (693.31 mm² vs 603.13 mm², P = .011) and ATPR at 60° (693.31 mm² vs 601.01 mm², P = .008) and 90° (619.68 mm² vs 563.97 mm², P = .037). ATPR-TTC significantly reduced peak contact pressure compared with ATPR at 45° (4.97 MPa vs 5.60 MPa, P = .015) and 60° (5.20 MPa vs 5.99 MPa, P = .026), with similar values to those of ATPR-2AC across all angles. In a cadaveric porcine model evaluating time-zero biomechanics, an anatomic transtibial pull-through repair with TTC using 2 suture tapes reduced extrusion and improved contact mechanics when compared with an isolated repair or a repair combined with centralization using 2 knotless anchors. When there are concerns of MME after a MMPRT repair, the addition of a TTC suture may provide better biomechanical properties than an isolated repair or a repair combined with centralization using 2 knotless anchors.