Prosthetic artificial joints are described, including hip, knee and shoulder joints. In some embodiments, a artificial joint prosthesis includes: a bone-facing surface of a artificial joint prosthesis, the bone-facing surface configured to face a bone-prosthesis interface in vivo; a non-contact surface of the artificial joint prosthesis, the non-contact surface adjacent to the bone-facing surface of the artificial joint prosthesis; at least one fluid deflection structure positioned adjacent to the non-contact surface, the fluid deflection structure positioned to deflect synovial fluid away from the bone-prosthesis interface in vivo; and a mechanism attached to the fluid deflection structure, the mechanism operable to move the fluid deflection structure to direct synovial fluid away from the bone-prosthesis interface in vivo.