Summary

This study evaluated biomechanical properties of four all-inside, meniscus-based repairs to radial tears of cadaveric human lateral menisci and found that reinforcing vertical suture meniscus repairs with horizontal suture significantly increases load to failure.

Abstract

Introduction

Meniscal injuries are among the most common orthopedic injuries in the United States. Radial meniscus tears were historically treated with partial meniscectomy, often leading to poor outcomes. Repairing radial tears preserves meniscal tissue, may delay knee degeneration, and leads to better long-term outcomes. Repair techniques for radial tears vary and should be evaluated for differences in biomechanical properties and failure mechanisms.1-3 All-inside, meniscus-based suture repairs have shorter operating times, minimize risk of nerve injury, and are increasingly possible with novel devices.3

Objective

Our objective was to evaluate four all-inside techniques to repair radial tears in human cadaveric lateral menisci. We chose two techniques – the Double Vertical (DV) and Double Vertical Cross (DVX) – that bridged the tear directly. We chose two other techniques – the All-inside Rebar (AR) and our novel Oblique Box (OB) – that added reinforcing stitches to engage the bridging stitches. We hypothesized that AR and OB would have higher load to failure than DV and DVX.

Methods

36 fresh-frozen lateral human menisci were randomized into four groups of nine. A complete radial tear was created at the midbody of the meniscus. Suture repairs were performed using 2-0 braided suture. We repaired the menisci using the DV, DVX, AR, and OB techniques with meniscus-based suturing to simulate the all-inside, meniscus-based approach with all knots tied on the superior surface of the menisci. The DV repair used two sutures in loops perpendicular to the tear. DVX used two sutures in loops that crossed over the tear. AR used two sutures in loops parallel to the tear acting as reinforcing rebar and two bridging sutures perpendicular to tear and outside rebar sutures. OB used two sutures to create a trapezoidal reinforcing box on either side of the tear and two bridging sutures in loops perpendicular to tear and inside the box. The repaired menisci underwent load to failure testing and were analyzed statistically.

Results

Failure occurred due to suture cutout. Repair constructs that lacked a reinforcing-type suture (DV and DVX) cut through or “cheese-wired” at lower loads than repairs with reinforcing sutures (AR and OB). The AR repair sustained the highest load to failure, nearly 3x stronger than the two non-reinforcing type repair constructs. Mean load-to-failure values for each repair group were 60 N ± 24.5 for DV, 58 N ± 17.4 for DVX, 168 N ± 33.9 for AR, and 105 N ± 9.0 for OB. These results show that reinforcing vertical suture meniscus repairs with some type of horizontal suture (e.g. AR or OB) significantly increases load to failure for all-inside, meniscus-based techniques.

Conclusions

In a cadaveric lateral meniscus model, all-inside radial repairs using rebar suture techniques had higher ultimate load to failure and reduced risk of “cheese wiring”. These data may provide useful information for surgeons to consider when deciding how to repair radial meniscus tears to maximize patient outcomes. Future biomechanical study should compare all-inside vs. inside-out repairs. Clinical outcomes of these various all-inside radial repair techniques are also critical.