An apparatus for the treatment of arthrofibrosis, has a base having first and second opposing ends and a hole or recess adjacent the first end for enabling connection of the base to a chair to restrict movement of the base relative to the chair. A block is removably attached to the base and is movable between the first and second ends for abutting the toes of a foot of a user of the apparatus placed between the block and the hole or recess. The block is slidable along a guide on the base for enabling adjustment of the block between the first and second ends of the base. A clamp clamps the block in position on the base.