Systems for determining force balance on a knee joint during a surgical procedure are disclosed. A system can include a tibial prosthesis (340). The tibial prosthesis can include a bearing component (342), a base component (344), and a shim component (346). The bearing component can have a superior articulating surface (460) and an inferior surface (348). The bearing component can include a top portion (816), a bottom portion (823), a frame (818) disposed between the top portion and the bottom portion, and a plurality of sensors (822) disposed between the frame and the bottom portion. The frame can have a plurality of apertures (828) corresponding in size or shape to the plurality of sensors. The base component can have a superior surface (352) and an inferior surface (476). The shim component can be configured to be slidable between the inferior surface of the bearing component and the superior surface of the base component in an anterior to posterior direction.
