  We consider three dimensional superconductors in class DIII with a four-fold
rotation axis and inversion symmetry. It is shown that such systems can exhibit
higher order topology with helical Majorana hinge modes. In the case of
even-parity superconductors we show that higher order topological
superconductors can be obtained by adding a small pairing with the appropriate
$C_4$ symmetry implementation to a topological insulator. We also show that a
hybrid case is possible, where Majorana surface cones resulting from
non-trivial strong topology coexist with helical hinge modes. We propose a bulk
invariant detecting this hybrid scenario, and numerically analyse a tight
binding model exhibiting both Majorana cones and hinge modes.
