An orthopedic device comprising: a footplate arranged to be positioned beneath the foot of a wearer, the footplate defining an anterior end, a first side, and a second side opposite the first side, the second side including a first guide; an upright support having a semi-rigid configuration and arranged to extend along a side of an ankle of the wearer, the upright support including a distal portion connected to the first side of the footplate and a proximal portion arranged to move toward and away from the anterior end of the footplate; a motion control system including an upper anchor element located above the second side of the footplate and having a second guide, and at least one tensioning element anchored to the second side of the footplate at the first guide and passing through the second guide of the upper anchor element, characterised in that the at least one tensioning element is arranged to allow movement of the second side of the footplate in a direction away from the upper anchor element until the at least one tensioning element becomes taut and to slide through the first and second guides (43, 45) when the proximal portion of the upright support moves toward and away from the anterior end of the footplate; the at least one tensioning element is arranged to pass and slide through a third guide longitudinally spaced from the first guide on the second side of the footplate; the second guide directs the at least one tensioning element toward the first and third guides (43, 47) and the motion control system is arranged to simultaneously change a length of the at least one tensioning element between the first and second guides (43, 45) and between the first and third guides (43, 47) in that the motion control system defines a linking system arranged to dynamically link sagittal plane motion to coronal plane motion. a footplate arranged to be positioned beneath the foot of a wearer, the footplate defining an anterior end, a first side, and a second side opposite the first side, the second side including a first guide; an upright support having a semi-rigid configuration and arranged to extend along a side of an ankle of the wearer, the upright support including a distal portion connected to the first side of the footplate and a proximal portion arranged to move toward and away from the anterior end of the footplate; a motion control system including an upper anchor element located above the second side of the footplate and having a second guide, and at least one tensioning element anchored to the second side of the footplate at the first guide and passing through the second guide of the upper anchor element, characterised in that the at least one tensioning element is arranged to allow movement of the second side of the footplate in a direction away from the upper anchor element until the at least one tensioning element becomes taut and to slide through the first and second guides (43, 45) when the proximal portion of the upright support moves toward and away from the anterior end of the footplate; the at least one tensioning element is arranged to pass and slide through a third guide longitudinally spaced from the first guide on the second side of the footplate; the second guide directs the at least one tensioning element toward the first and third guides (43, 47) and the motion control system is arranged to simultaneously change a length of the at least one tensioning element between the first and second guides (43, 45) and between the first and third guides (43, 47) in that the motion control system defines a linking system arranged to dynamically link sagittal plane motion to coronal plane motion.