A biomechanical analysis of an engineered cell-scaffold implant for cartilage repair

This study evaluated the biomechanical and physical properties of newly for med cartilage engineered from isolated chondrocytes in combination with mat rix components. Four groups of constructs were studied. Group A consisted o f lyophilized articular cartilage chips mixed with a cell-fibrinogen soluti on and thrombin to obtain constructs made of fibrin glue, chondrocytes, and cartilage chips. Group B constructs were prepared using fibrin glue and ca rtilage chips without cells. Group C contained chondrocytes in fibrin glue without chips, and group D comprised constructs of fibrin glue alone. Speci mens were implanted in the subcutaneous tissue of nude mice for 9 weeks. At necropsy the specimens were examined grossly, physically, biomechanically, and histologically, The original, preimplantation mass of the constructs w as retained only in experimental group A. Histological analysis of specimen s in experimental groups A and C demonstrated the presence of newly formed cartilaginous matrix, whereas only fibrotic tissue was observed in control groups B and D. Biomechanical analysis demonstrated higher mean values of e quilibrium modulus in the experimental samples of group A with respect to a ll control groups. This study demonstrated that adding lyophilized cartilag e chips to a fibrin glue-engineered cartilage construct maintains the biome chanical properties and the original mass after medium-/long-term in vivo t ransplantation.