Abstract: Disclosed herein is a device for measuring knee adduction moment or knee abduction moment, which has: (a) a thigh portion, comprising a tissue interface, having two or more force sensors, operatively coupled to a data processing unit, configured to be positioned generally on the lateral and medial sides of the leg, when in use; (b) a shank portion, comprising a tissue interface, having two or more force sensors, operatively coupled to a data processing unit, configured to be positioned generally on the lateral and medial sides of the leg, when in use; (c) a knee assembly, configured to rotate with the knee, rotatably coupling the thigh portion to the shank portion; and (d) at least two attachment loci, wherein the knee assembly is attached to the thigh portion at a first attachment locus, and wherein the knee assembly is attached to the shank portion at a second attachment locus.