Abstract: A leg brace and method for forming thereof is provided. The brace includes a frame formed of at least a thermoplastic material. A harness is fixed to the frame, the harness being retained adjacent a user's leg during use. The leg brace may be further formed with a tibial restricting portion running along and substantially parallel to the medial shaft of a user's tibia during use, thereby preventing any unwanted movement or rotation of the user's tibia. The brace is formed by forming a brace core of a mixture of a thermoplastic material and a blowing agent and then placing a composite material in contact with the core. Next, the core and composite material are heated in a mold to a temperature sufficient to allow the thermoplastic material to become molten, causing the blowing agent to expand and force the composite material against an interior wall of the mold cavity and to form a thermoplastic cellular core.