The invention relates to medical implants, including spinal implants and bone grafts, for fixation and integration with hard tissue. The bone medical implants include at least one rotational fixation mechanism that further includes or is attached to one or more sharp protrusions configured to penetrate and become lodged into hard tissue to provide support and positional stability. Such support is useful to ensure that the spinal bone graft may be used without additional stabilizing or anchoring structures, such as supporting plates or screws.