Moreover, biophysical stimulation is able to inhibit the catabolic effects of the inflammatory cytokines on the joint cartilage32 and to stimulate the synthesis of proteoglycans and the local production of BMPs, TGF-α, and IGF-I;33 PEMFs exert a chondroprotective effect in vivo on osteoarthritis,34 which may play a fundamental role in the treatment of early stages of osteonecrosis of the femoral head by limiting the damage induced by inflammation and preserving cartilage and subchondral bone exerting a short term effects. This evidence concerns the gene IGF1 and osteonecrosis.