In vitro and in vivo comparison of five biomaterials used for orthopedic soft tissue augmentation

Objective - To compare biomaterials used in orthopedics with respect to in vitro cell viability and cell retention and to in vivo tissue healing and regeneration. Animals - 65 adult female Sprague-Dawley rats and synovium, tendon, meniscus, and bone marrow specimens obtained from 4 adult canine cadavers. Procedures - Synovium, tendon, meniscus, and bone marrow specimens were used to obtain synovial fibroblasts, tendon fibroblasts, meniscal fibrochondrocytes, and bone marrow-derived connective tissue progenitor cells for culture on 5 biomaterials as follows: cross-linked porcine small intestine (CLPSI), non-cross-linked human dermis, cross-linked porcine dermis, non-cross-linked porcine small intestine (NCLPSI), and non-cross-linked fetal bovine dermis. After 1 week of culture, samples were evaluated for cell viability, cell density, and extracellular matrix production. Biomaterials were evaluated in a 1-cm abdominal wall defect in rats. Each biomaterial was subjectively evaluated for handling, suturing, defect fit, and ease of creating the implant at the time of surgery, then grossly and histologically 6 and 12 weeks after surgery. Results - All biomaterials allowed for retention of viable cells in culture; however, CLPSI and NCLPSI were consistently superior in terms of cell viability and cell retention. Cell infiltration for NCLPSI was superior to other biomaterials. The NCLPSI appeared to be replaced with regenerative tissue most rapidly in vivo and scored highest in all subjective evaluations of ease of use. Conclusions and Clinical Relevance - These data suggested that NCLPSI and CLPSI have favorable properties for further investigation of clinical application in orthopedic tissue engineering.