Material Properties of Suture Augmentation of Knee Medial Collateral Ligament Repair Did Not Influence Length Changes or Failure Loads in a Caged Porcine Model

Abstract

To investigate whether the biomechanical properties of the healed superficial medial collateral ligament (sMCL) repaired by augmentation vary depending on the material properties of the suture augmentation. In 8 of 10 porcines (16 hindlimbs), the sMCL was detached from the femoral attachment using a scalpel under intubated general anesthesia. sMCL repair was performed using an ultra-high-molecular-weight polyethylene (UHMWPE) tape for the right hindlimbs and polyester tape (PE) for the left hindlimbs. They were sacrificed at 4 weeks postoperatively. The remaining 2 animals were assigned to the native control group (left and right hindlimb; n= 4). All connective tissues and suture augmentation, except for the repaired sMCL, were removed, and their biomechanical properties were evaluated. No significant differences were observed in the upper yield load (PE group, 247.4 ± 116.0 N; UHMWPE group, 279.9 ± 95.7 N; and sham group, 231.6 ± 50.6 N; P= .70), maximum yield load (PE group, 310.1 ± 166.1 N; UHMWPE group, 334.6 ± 95.2 N; and sham group, 290.9 ± 42.3 N; P= .84), linear stiffness (PE group, 43.3 ± 16.5 N/mm; UHMWPE group, 52.0 ± 28.2 N/mm; and sham group, 44.7 ± 7.2 N/mm; P= .66), and elongation at failure (PE group, 9.4 ± 4.3 mm; UHMWPE group, 9.1 ± 2.7 mm; and sham group, 10.1 ± 2.1 mm; P= .89). Statistical analysis of failure modes showed no significant difference between the groups (P= .21). The material properties of suture augmentation used for sMCL repair did not significantly influence length changes during cyclic loading, postoperative structural properties, or failure modes. The results of this study provide valuable information regarding the efficacy of suture augmentation repair regardless of the materials used.