Medical device delivery systems and methods for making and using medical device delivery systems are disclosed. An example medical device delivery system may include an outer sheath (12). An inner catheter (14) may be disposed within the outer sheath. An implant (16) may be releasably coupled to the inner catheter. The implant may be configured to shift between a first elongated configuration and a second expanded configuration. A push-pull rod (84) for shifting the implant between the first configuration and the second configuration may be coupled to the inner catheter. A locking assembly may be disposed about the push-pull rod. At least a portion of an outer surface of the push-pull rod may have a non-circular cross-sectional shape. The locking assembly may have an interior passageway with a non-circular cross-sectional shape corresponding to the non-circular cross-sectional shape of the push-pull rod.
