Cartilage repair with chondrocytes in fibrin hydrogel and MPEG polylactide scaffold: an in vivo study in goats

Polylactic acid polymers have been used extensively as biomaterials and have shown promising properties for cartilage tissue engineering. Numerous scaffold materials exist and the optimal scaffold needs to be identified. We have tried to assess the possibilities for cartilage repair by the use of two different scaffold techniques; autologous chondrocytes in a fibrin hydrogel and a novel MPEG-PLGA scaffold, where autologous chondrocytes are immobilized within the MPEG-PLGA scaffold by a fibrin hydrogel. Twenty adult goats were used for the study. A 6 mm circular full-thickness cartilage defect was created in both medial femoral condyles. The defects were randomized to the following four treatment groups. (1) Empty defect (control). (2) Subchondral drilling (control). (3) Fibrin hydrogel with autologous chondrocytes. (4) Fibrin hydrogel/chondrocyte solution in a MPEG-PLGA porous scaffold. Animals were followed for 4 month. Eight defects in each treatment group completed the study. ICRS macroscopic scoring (0-12). Indentation test was performed to assess stiffness of repair tissue. Histological analyses was performed using O'Driscoll and Pineda cartilage scores as well as percentage tissue filling of the defects. The MPEG-PLGA/chondrocytes scaffold was the superior treatment modality based on the macroscopic surface score, histological scores and defect filling. The mechanical test demonstrated no difference between treatment groups. The MPEG-PLGA/chondrocyte composite demonstrated significantly better cartilage repair response than empty defects, osteochondral drilling and fibrin hydrogel with chondrocytes. The novel MPEG-PLGA scaffold in combination with chondrocytes need further studies with respect to longer follow-up times.