During the last decade, scaffold-based tissue engineering has emerged as a potential alternative for organ transplantation and tissue grafts, particularly bone and cartilage tissues. The engineered scaffold should be biocompatible and biodegradable to allow cells to produce their extracellular matrix. Most of the previous studies demonstrated the need for solvent treatment of foamed scaffolds to add biocompatible and biodegradable materials such as chitosan (Ch) inside the scaffolds’ pores to promote cell proliferation, leading to unwanted residual solvents deeply trapped inside the scaffolds’ matrix. In this work, we used an original technique to avoid this post-foaming solvent treatment of open-cell poly(lactic acid) (PLA) scaffolds. First, graft copolymerization of chitosan with PLA was done to obtain a Ch-g-PLA copolymer. This modification aims to ensure good interaction between Ch and the pore surface of PLA scaffold and effectively promotes Ch/PLA adhesion. Second, we prepared by internal mixing method a chemical foaming composite (CFCO) composed of Ch-g-PLA adequately mixed with a chemical foaming agent (azodicarbonamide, ADC) under a mixing temperature below ADC decomposition temperature. Finally, this CFCO was used to develop by compression molding PLA open-cell porous scaffolds. Because the CFCO contains Ch-g-PLA, the latter is directly projected on the surface of the developed pores during the decomposition of the foaming agent, leading to strong adhesion between Ch-g-PLA and the PLA matrix. This was confirmed FTIR analyses. Also, improved osteoblast adhesion and proliferation with the so developed scaffold were respectively confirmed by Hoechst staining and MTT cell proliferation assay.