Double-loop suture repair of radial meniscal tears provides favourable biomechanical performance compared to conventional repair techniques: A biomechanical study

Abstract

Purpose: Radial meniscal tears significantly impact knee biomechanics and can lead to joint degeneration if untreated. While various suture techniques exist, no consensus has been reached on the optimal method. The hypothesis was that the double-loop suture can significantly reduce displacement between tear segments and achieve a higher ultimate failure load than conventional techniques. This study aims to biomechanically compare conventional repair techniques to a novel double-loop suture to enhance tensile strength, reduce displacement and improve meniscal repair outcomes.

Methods: Forty fresh-frozen porcine menisci with full-thickness radial tears were repaired using four techniques: double vertical, double horizontal, cross-tie and double-loop sutures. Biomechanical testing included cyclic loading (200 cycles, 5-19 N) and ultimate failure load evaluation. Key outcomes measured were displacement after cyclic loading, failure load, and failure modes. A one-way analysis of variance (ANOVA) was conducted to identify significant differences among groups.

Results: Among the evaluated techniques, the double-loop suture demonstrated the highest ultimate failure load (111.1 ± 17.3 N, p < 0.01). Displacement after cyclic loading was minimal across techniques, except for the double vertical suture, which showed significantly higher displacement. Knot breakage was the primary failure mode in conventional sutures, whereas the double-loop suture also exhibited tissue cutting.

Conclusions: The double-loop suture provides superior biomechanical performance, offering greater tensile strength and stability than conventional methods. Its simplicity and arthroscopic applicability highlight its potential for advanced meniscal repair. The double-loop suture could be applied in the arthroscopic setting, improving the outcomes for treating radial tears. Further clinical studies are needed to confirm long-term efficacy.

Level of evidence: Level IV, cadaveric study.

Keywords: displacement; knee; load; meniscus; radial tear.

Figure 1

Schematic representation of the four suture techniques evaluated: (a) Double horizontal suture, (b) cross‐tie suture, (c) double vertical suture and (d) double‐loop suture.

Figure 2

Stepwise execution of the double‐loop suture technique on fresh‐frozen porcine menisci. (a) Passage of the first needle through the meniscus, creating the initial loop on the inner surface of the tear. (b) Passage of the second needle, forming a second loop on the opposite side of the tear. (c) The second loop is threaded through the first loop, securing the construct in place. (d) Tension is applied to the suture by pulling the thread of the second loop, ensuring tight approximation of the tear edges. (e) Finalisation of the repair with the external knot tying after the free suture end is pulled through, securing the meniscal tear.

Figure 3

Schematic representation of the double‐loop suture technique for radial meniscal tear repair. (a) A first suture limb is passed through the inner edge of the radial tear, creating the initial loop on the inner meniscal surface. (b) A second pass is made on the opposite side of the tear, forming a second loop on the outer side of the radial defect. (c) The second loop is threaded through the first loop, interlocking the two suture limbs. (d) The first suture limb is pulled to draw the second loop through the meniscal tissue, creating circumferential compression (red arrows indicate direction of traction). (e) Both suture limbs are now tensioned externally to approximate the tear edges and ensure stability of the repair. (f) Final knot tying is performed on the capsular side, securing the repair construct.

Figure 4

Representative load‐displacement curve from biomechanical testing of meniscal suture repairs. A. Preloading phase: A controlled force of up to 5 N is applied to eliminate slack and precondition the meniscal tissue. B. Cyclic loading phase: The specimen undergoes 200 cycles of repetitive loading between 5 N and 19 N, simulating physiological stresses encountered in vivo. The shaded red area represents the accumulated energy dissipation during cyclic loading. C. Progressive loading phase: The load increases steadily under displacement control, evaluating the mechanical stability and resistance of the repair technique. D. Failure point: The ultimate failure load is reached, characterised by a sudden drop in force, indicating structural failure of the repair (e.g., suture breakage, tear extension, or suture pullout). mm, millimetre; N, Newton.

Figure 5

Comparison of ultimate failure load across the four suture techniques. N, Newton.

Figure 6

Comparison of displacement after 200 loading cycles for the four suture techniques. mm, millimetre.