Objective To explore the biosafety of a novel elastic internal tension-relieving augmentation tape (hereinafter referred to as “novel tension-relieving tape”) for posterior cruciate ligament (PCL) reconstruction and its regulatory effects on graft healing and tendon-bone integration via a Diannan miniature pig PCL reconstruction model. Methods Eighteen female Diannan miniature pigs aged 6-8 months were randomly assigned to tension-relieving group and non-tension-relieving group, with 9 pigs per group. One hind limb of each pig was randomly selected as the experimental limb for PCL reconstruction (n=9): autologous tendon combined with the novel tension-relieving tape was applied in tension-relieving group, while only autologous tendon was used in non-tension-relieving group; the contralateral hind limb was served as self-normal control. Postoperative general conditions of animals were observed, and complete blood count (CBC) tests were performed. Knee joint specimens were harvested at 3, 6, and 12 months postoperatively for gross observation and Marburger Arthroscopy Score (MAS) evaluation. Toluidine blue staining, safranin O-fast green staining, hematoxylin-eosin (HE) staining, collagen type Ⅰ/Ⅲ immunohistochemistry staining, and Sirius red staining were conducted to assess tendon-bone interface healing. HE staining of liver, lung, spleen, and the tissues around tendon-bone implantation area were performed to evaluate the biosafety of the material. Results All animals survived to the experimental endpoint. The indicators of CBC tests of both groups before operation and at different time points after operation, including white blood cell counting, hemoglobin, platelet counting, and neutrophil percentage, remained within normal physiological ranges, with no significant intergroup differences (P>0.05). No difference was found in histological scores of liver, lung, and spleen between groups (P>0.05). No giant cell aggregation, chronic inflammatory granuloma, or tissue erosion and degradation was observed in soft tissues around the implantation area, which indicated that the novel tension-relieving tape exhibited favorable biocompatibility without systemic or local toxic reactions. At 3 and 6 months postoperatively, the tension-relieving group obtained superior MAS score, tendon-bone healing score, nuclear morphological score, collagen type Ⅰ immunohistochemical score, and collagen volume fraction (P<0.05) as well as more regularly arranged elastic fibers compared with non-tension-relieving group, whereas no intergroup difference was detected in collagen type Ⅲ immunohistochemical score (P>0.05). At 12 months postoperatively, the degree of graft ligamentization and tendon-bone interface integration were comparable between the two groups, and no significant intergroup difference was observed in all above indicators (P>0.05). Conclusion The novel tension-relieving tape possesses reliable biosafety. It can effectively accelerate early graft collagen remodeling and tendon-bone interface healing after PCL reconstruction, and improve early knee joint stability.
