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

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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. CLINICAL RELEVANCE: The results of this study provide valuable information regarding the efficacy of suture augmentation repair regardless of the materials used.