The canonical Arnowitt-Deser-Misner (ADM) Hamiltonian with next-to-leading order (NLO) spin-spin coupling [J. Steinhoff, S. Hergt, and G. Schäfer] is converted into the effective-one-body (EOB) formalism of T. Damour, P. Jaranowski, and G. Schäfer for the special case of spinning black hole binaries whose spins are aligned with the angular momentum. In particular, we propose to include the new terms by adding a dynamical term of NLO to the Kerr parameter squared entering the effective metric. The modified EOB Hamiltonian consistently reduces to the Kerr Hamiltonian as the mass-ratio tends to zero; moreover, it predicts the existence of an innermost stable circular orbit. We also derive, for the general case of arbitrarily oriented spins but in the vanishing massratio limit, a coordinate transformation that maps the NLO spin-spin contribution of the ADM Hamiltonian to the EOB Hamiltonian.