Medical implants disclosed herein may include an interior space and at least one bone on-growth structure within the interior space. The bone on-growth structure may include a root coupled to an interior surface of the implant, or to a mesh insert disposed within the interior space of the implant. The root may extend into the interior space toward another opposing interior surface of the implant. The bone on-growth structure may include a plurality of branches coupled to the root via a plurality of junctions. The plurality of branches may project at a plurality of different angles with respect to the root. The plurality of branches may each terminate within the interior space, or alternatively, one or more branches may contact opposing interior surfaces of the implant. The medical implants may also include one or more channels to enhance bone growth within the interior space.