Tissue engineering of a small hand phalanx with a porously casted polylactic acid-polyglycolic acid copolymer

In this study, we evaluate a porous polylactic acid-polyglycolic acid (PLGA) polymer in tissue engineering a small hand phalanx. The PLGA polymer was processed with a unique solvent cast/salt-leaching method in the shape of a little finger distal phalanx. An 85% polylactic acid (PLA)/15% polyglycolic acid (PGA) copolymer was determined to be the most favorable mixture for creating a small digital phalanx in precise shape and size. The pore sizes averaged 250-425 microm. Bovine periosteum was wrapped around each phalangeal polymer. Chondrocytes were injected into the articular end. Six constructs were surgically placed into a dorsal subcutaneous pocket of an ethylic mouse. After 8 (n=2) or 16 (n = 4) weeks, all implants demonstrated growth of bone and cartilage in the shape and size of a small hand phalanx, which was maintained throughout the study period. Histologic evaluation showed a homogeneous presence of bone and cartilage, with progressive tissue differentiation and matrix production from 8 to 16 weeks. The tissue-engineered bone formed through an endochondral ossification process. Articular cartilage was maintained where the chondrocytes were placed. These findings suggest that the porous PLGA polymer is an effective synthetic biodegradable device to support and guide tissue growth of bone and articular cartilage in the shape of a human phalanx.