Abstract: The present disclosure describes systems, devices, and methods for determining stability of a joint of a living subject. In one aspect, a force-measuring device for determining stability of a joint of a living subject is provided. In some examples, the force-measuring device includes a mitt frame configured to receive a hand of a user therein, one or more first force sensors, and one or more second force sensors. The mitt frame may include a palm portion configured to receive a palm of the user therein, and a finger portion configured to receive fingers of the user therein. The one or more first force sensors may be coupled to the palm portion and disposed on an exterior surface of the palm portion. The one or more second force sensors may be coupled to the finger portion and disposed on an exterior surface of the finger portion.

Abstract: A method for improved rotational alignment of the bones in joint surgery is described. The method involves the tracking of the relative motion of a third bone in with respect to the movement of the first and second bone. In one aspect of the invention, the motion of the patella is used to derive the axis of rotation of the femoral and tibial components in total knee arthroplasty, either alone or in combination with other techniques.