an upper plate including an upper articular surface and a side wall extending around a perimeter of the upper articular surface, the upper articular surface having condylar portions each defining a concave surface configured to articulate with a corresponding condylar portion of a femoral component, the side wall defining a recess;

an upper arm separately formed from the upper plate and including a first plate with a front end, the front end being shaped to correspond to the recess of the side wall such that the upper plate is configured to be slidably coupled to the first plate of the upper arm such that at least a portion of the side wall extends below the first plate to couple the upper plate to the upper arm;

a lower arm including a second plate, the second plate having substantially the same size and shape as the first plate; and

an adjustment mechanism connected to the upper and lower arms and being configured to move the upper and lower arms relative to each other.