Magnetic devices for altering loading across joints

Magnetic devices for altering loading across joints or fracture sites. Magnetic devices may be bone screws having a shaft, in which the shaft comprises a bore that is configured to fit a magnet. A bone plate \comprising apertures can fit the bone screws. The bone plate may be fastened to bone using the bone screws, and the bone screws may be oriented to generate attractive or repulsive forces. Further, 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. 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.