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

Purpose 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. Methods 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. Results 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 mm 2 vs 603.13 mm 2 , P = .011) and ATPR at 60° (693.31 mm 2 vs 601.01 mm 2 , P = .008) and 90° (619.68 mm 2 vs 563.97 mm 2 , 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. Conclusions 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. Clinical Relevance 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.