A ligament balancer 10 for a knee is disclosed comprising a first guide portion 14 having a first guide hole 26 extending there through, and a second guide portion 16 having a second guide hole 28 extending there through, the first and second guide portions 14, 16 being moveable with respect to each other along a movement axis, the balancer 10 being adapted such that, in use, the movement axis is substantially parallel to the anterior/posterior axis of a distal femoral surface.Also disclosed is a kit of parts comprising the ligament balancer and a drill guide 40 for a knee, the drill guide 40 comprising first and second connected arms 42, 44, each arm comprising at least two guide openings 50, 52, 54, 56 extending there through, the guide openings being spaced longitudinally along each arm 42, 44, longitudinal axes 46, 48 of the first and second arms 42, 44 intersecting at a predetermined angle.
