an assembly for an orthosis includes a flexure unit for joining two parts of the orthosis , such as a foot shell and an ankle or leg shell . one end portion of the flexure unit is supported on a housing that permits angular adjustment of the end portion of the flexure unit relative to the section of the orthosis on which the end portion is mounted . the angular adjustment is accomplished by utilizing a positive drive between a base portion and a housing that traps the end portion of the flexure in position on the base . this permits varying the assisting force , for example , toe lift , of the flexure unit between orthosis shell parts when the orthosis is worn .