Abstract: A knee brace comprising upper and lower leg-engaging/embracing parts (thigh and calf pieces) connectable around upper and lower parts of the leg above and below the knee joint with the upper and lower leg embracing parts having upper and lower brace members respectively interconnected by at least one joint, wherein the at least one joint means each comprises at least one link member pivotally connected at pivot points to rotate about a pivotal axis on each of the brace members with the at least one link member being provided for holding brace members together, and wherein the end region of a first said brace member has a slot defined between two end arm portions and within the slot space or forming a defining portion thereof, a first gear is provided and such is engaged by a second gear on the end of the second brace member which second gear is displaceable in the slot to engage the first gear and wherein the first and second gears each lie on arcs each concentric with the pivot point of the brace member on w