A limb positioning system includes a clamp assembly, a pylon and bar assembly, a sled assembly, and a limb positioning assembly. The clamp assembly is configured to attach to a bed rail of a surgical table and to accept a pylon connected to a bar. The pylon may have a plurality of pylon bars that are secured by the clamp assembly. A base bar may extend from the pylon, and may be attachable to an extension bar to provide a longer track along which the sled assembly may slide. The sled assembly may be biased to be locked with respect to the base bar. The limb holding assembly may include a boot coupled to the sled via a connector near the heel. The connector may be tapered and insertable into a correspondingly tapered section of a ball that sits within the sled assembly, the ball being capable of polyaxial motion.