Methods and devices for the regulation of type II collagen gene expression in cartilage cells via the application of specific and selective fields generated by specific and selective electric and electromagnetic signals in the treatment of diseased or injured articular cartilage. By gene expression is meant the up regulation or down regulation of the process whereby specific portions (genes) of the human genome (DNA) are transcribed into mRNA and subsequently translated into protein. Methods and devices are provided for the targeted treatment of injured or diseased cartilage tissue that include generating specific and selective electric and electromagnetic signals that generate specific and selective fields optimized for type II collagen gene expression and exposing cartilage tissue to the specific and selective fields generated by specific and selective signals so as to regulate type II collagen gene expression in such cartilage tissue. The resulting methods and devices are useful for the targeted treatment of osteoarthritis, rheumatoid arthritis, cartilage injury, and cartilage defects.