Bone screw assemblies that can include a screw, housing, snap ring, saddle, set screw, and rod are described herein. The bone screw assemblies can allow for polyaxial or uniplanr movement of the screw relative to the housing. A threaded portion of the screw can be coated with a hydroxyapatite (HA) coating. The screw can have a triple lead thread configuration. The bone screw assembly may be modular.
