An elbow-forearm anti-rotation support system and process that do not require a hardenable material. The system includes an orthopedic support such as a wrist-hand orthosis, wrist-hand-thumb orthosis, or cast, joined to a bottle-shaped forearm wrap with opposed flaps formed into a clamshell. Proximal elbow flaps include a center elbow region that extends from the proximal end of the forearm wrap. A U-shaped reinforcement stay is disposed on the center elbow region and attaches to the forearm flaps. Cross straps extending from the proximal elbow flaps attach to the forearm flaps, and a closure strap secures the two flaps together. Hook and loop fasteners extending from the distal edge of the forearm wrap attach the forearm wrap to the orthopedic support.