Magnetic devices for altering loading across joints

Methods of reducing loading across a cartilaginous joint, or of reducing pain in a cartilaginous joint caused by cartilage damage in the joint. The methods involve implanting one or more magnetic devices in the bones, or affixing one or more magnetic devices onto the surface of the bones, that form the joint. For example, to reduce loading or reduce pain in a knee joint, one or more magnetic devices maybe implanted in the femur and in the tibia. The magnetic devices are oriented to generate a repulsive magnetic force between the one or more magnetic devices of each of the bones forming the joint.