A system that includes: a force sensor assembly adapted to monitor a load as applied on a subject's knee joint when the force sensor assembly remains in direct contact with the subject's lower extremity and the load is monitored from inside a main magnet of an MRI scanner; a mobile unit comprising tracks configured to adjust a position of the force sensor assembly; a stationary base on which the mobile unit and the force sensor assembly are located, the mobile unit translatable solely axially on the stationary base; and a processor coupled to the force sensor assembly and programmed to read information encoding the load being monitored by the force sensor assembly, wherein an MRI scan of the knee joint is initiated only when a pre-determined load has been applied to the subject's knee joint for a pre-determined period of time.