In functional hallux limitus, there is a lack of motion of the big toe joint that occurs only with weight bearing. There are no bone spurs or other bone problems that limit the motion of the big toe joint without weight bearing.
With weight bearing the first metatarsal moves upward and the medial collateral ligament of the first MTPJ becomes displaced at an angle to the floor. In this position the ligament is acting as a tension band and restricting the motion of the big toe joint.
By elevating the big toe, normal alignment (parallel to floor) is achieved of the medial collateral ligament and normal unrestricted motion is allowed of the first MTPJ.
Once this mechanism is understood, the Cluffy Wedge is the natural, logical, solution to this problem.