Surgical treatment of meniscal extrusion associated with medial meniscus posterior root tears: An in-vitro biomechanical study comparing centralization techniques

Boksh, Khalis (2025). Surgical treatment of meniscal extrusion associated with medial meniscus posterior root tears: An in-vitro biomechanical study comparing centralization techniques. University of Birmingham. M.Sc.

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Abstract

Background

Medial meniscus posterior root tears (MMPRTs) are associated with meniscal extrusion and can alter tibiofemoral contact mechanics. This accelerates chondral injury, leading to early degeneration of the knee joint. Despite the success of root repairs, post-operative extrusion can persist, with suboptimal healing and progressive osteoarthritis. Centralization techniques as an adjunct to root repair have recently emerged to counter extrusion. This includes the transtibial and suture anchor techniques. However, biomechanical comparison between the two are required to determine the most suitable technique.

Purpose
To quantitatively compare the tibiofemoral contact mechanics and extent of meniscal extrusion between an isolated root repair, and a repair in conjunction with a transtibial or suture anchor centralization technique to determine which method closely restores the normal loading profile of the knee.

Methods
Twelve porcine knee joints were used and underwent testing under the following conditions: (1) intact state; (2) MMPRT; (3) anatomical transtibial pull-through repair (ATPR); (4) ATPR and transtibial centralization (TTC); and (5) ATPR and two-anchor centralization (2AC). The testing protocol loaded knees with a 200 N axial compressive force at 4 flexion angles (30°, 45°, 60° and 90°). Two-dimensional motion analysis using digital photography and imaging software was used to measure extrusion. Peak contact pressure and contact area were analysed in a customized MATLAB program.

Results

Medial meniscus extrusion was significantly reduced after ATPR + TTC than after ATPR or ATPR + 2AC at 60° (2.68 mm vs. 4.39 mm vs. 4.09 mm, p < 0.001), and 90° (2.99 mm vs. 4.75 mm vs. 4.36 mm, p < 0.001). The contact area was significantly greater with ATPR + TTC compared to ATPR + 2AC at 60° (693.31 mm2 vs. 603.13 mm2, p = 0.011), and with ATPR at 60° (693.31 mm2 vs. 601.01 mm2, p = 0.008) and 90° (619.68 mm2 vs 563.97 mm2, p = 0.037). ATPR + TTC significantly reduced peak contact pressure compared to ATPR at 45° (4.97 MPa vs. 5.60 MPa, p = 0.02), and 60° (5.20 MPa vs. 5.99 MPa, p = 0.03), whilst ATPR + 2AC only reduced such pressure at 60° (5.23 MPa vs 5.99 MPa, p = 0.03). Both centralization techniques showed similar peak contact pressure at all angles.

Discussion

The ATPR + TTC best restored extrusion and contact mechanics of the knee when compared to other fixation methods. Except for contact pressure at 60°, there were no differences between ATPR and ATPR + 2AC. Future comparative trials are required to determine the true clinical efficacy between the techniques.

Type of Work:

Thesis (Masters by Research > M.Sc.)

Award Type:

Masters by Research > M.Sc.

Supervisor(s):