Orthodontic positioning devices, and related methods and systems, are disclosed for use with one or more orthodontic elastic members. The disclosed devices are configured to couple with an orthodontic elastic member so as to react a force from the elastic member into the appliance to, for example, generate traction forces on the patient's teeth to produce a desired occlusion. A positioning device includes a patient removable tooth positioning appliance having teeth receiving cavities shaped to receive and apply a resilient positioning force to a patient's teeth. The appliance includes a hook configured to interface with an orthodontic elastic member. The hook can be configured to be offset from a surface of a tooth when the appliance is coupled with the patient's teeth and no elastic member is coupled with the tooth. The hook can be curved so that the hook is more retentive on the aligner. The hook can be reinforced so that the reinforcement resists deformation when the elastic is in place.