ARTICULAR-CARTILAGE REPAIR USING ALLOGENEIC PERICHONDROCYTE-SEEDED BIODEGRADABLE POROUS POLYLACTIC ACID (PLA) - A TISSUE-ENGINEERING STUDY

Efforts to expand treatment options for articular cartilage repair hav e increasingly focused on the implantation of cell-polymer constructs. The purpose of this study is to determine the suitability of porous D ,D-L,L-polylactic acid as a carrier for delivering repair cells obtain ed from rib perichondrium into full-thickness articular cartilage defe cts. In vitro characterization of perichondrocyte-polylactic acid comp osite grafts was combined with in vivo assessment of the early articul ar cartilage repair in a clinically relevant model. Using a fluorescen t double-stain protocol to visualize live and dead cells in situ, prim ary cells cultured from perichondrium were found to be capable of atta ching to and surviving within a porous D,D-L,L-polylactic acid matrix. These perichondrocyte-polylactic acid composite grafts were then impl anted within osteochondral defects drilled into the left medial femora l condyles of 16 adult New Zealand white rabbits. Experimental animals were sacrificed 6 weeks after implantation and the repair tissue was evaluated grossly, histologically, and biochemically. Grossly, 96% (15 /16) of the experimental animals demonstrated repairs consisting of a smooth, firm neocartilage which appeared similar in color and texture to the surrounding articular surface. Matrix staining for cartilaginou s protein was seen surrounding chondrocyte-like cells in the cartilage regions of the repair. Cellular alignment was found to be related to scaffold architecture. These results suggest that scaffolds composed o f porous D,D-L,L-polylactic acid support the growth of cartilaginous r epair tissue and are compatible with both in vitro and in vivo surviva l of chondrogenic cells. (C) 1995 John Wiley and Sons, Inc.