Influence of Sutures on Cartilage Integrity: Do Meniscus Sutures Harm Cartilage? An Experimental Animal Study

Purpose: To evaluate whether different suture materials in meniscal repair may harm cartilage. Methods: A preloaded linear friction testing setup including porcine knees with porcine cartilage, porcine meniscus, and different suture materials (braided nonabsorbable, absorbable monofilament) was used. Five groups with different tribological pairs were tested: cartilage on meniscus (control), cartilage on cartilage (control No. 2), and cartilage on different meniscus sutures (3 groups). Cartilage integrity was analyzed macroscopically by the India ink method and histologically using Giemsa-eosin–stained undecalcified methyl methacrylate sections. Cartilage lesions were classified by using a quantitative scoring system. Results: The control groups did not show cartilage damage, either macroscopically or histologically. Loading cartilage with sutured menisci led to significant damage of the superficial radial and transitional zones with braided nonabsorbable (P =.03) and absorbable monofilament (P =.02) sutures at final examination. Menisci sutured with braided nonabsorbable material resulted in deeper damage to the cartilage. However, there were no significant differences between the suture materials. Sutures oriented perpendicular to surface motion led to a larger defect than parallel-oriented sutures. Conclusions: Braided nonabsorbable and absorbable monofilament suture materials cause significant damage to cartilage during long-term cyclic loading in vitro. The extent of damage depends on suture orientation. Clinical Relevance: This study provides data on the extent to which different suture materials in meniscus repair may harm cartilage.