An ankle-foot orthosis (1 60) for resisting plantarflexion of a patients foot, the orthosis comprising: an orthotic structure (10 60) formed of a first tubular portion (12 62) and a second tubular portion (14 64) set at an angle to said first portion, wherein: the orthotic structure (10) is formed from a resiliently flexible material having a resilience chosen to be sufficient to provide a resistance to flexure that is appropriate for correction of the particular degree of plantarflexion experienced by the patient said first portion (12 62) comprises first and second regions (42, 44 74, 76) that have been overlapped and permanently secured one to the other to form a tube that fits closely about the patients foot said second tubular portion (14 64) is capable of being opened for insertion of the patients foot into the tube formed by said first portion (12 62), and for insertion of at least a portion of the patients lower leg into said second portion (14 64), and said orthosis further comprises a closure (32 66, 68 82 84, 86) for securing said second portion (1464) in a closed position in which the second tubular section closely fits about the lower leg of the patient in use. Also disclosed are a resiliently flexible structure (50) that is formable into an ankle-foot orthosis, a method of manufacturing a resiliently flexible structure for fitting to the foot and lower leg of a patient, and a method of fitting a resiliently flexible structure to the foot and lower leg of a patient to provide an ankle-foot orthosis.Linvention porte sur une orthèse cheville-pied (1 60) pour résister à la flexion plantaire du pied dun patient, lorthèse comportant : une structure orthétique (10 60) constituée dune première partie tubulaire (12 62) et dune seconde partie tubulaire (14 64) réglée à un angle par rapport à ladite première partie, la structure orthétique (10) étant formée à partir dun matériau flexible de façon élastique ayant une résilience choisie pour être suffisante afi
