  We study the planar orthogonal drawing style within the framework of partial
representation extension. Let $(G,H,{\Gamma}_H )$ be a partial orthogonal
drawing, i.e., G is a graph, $H\subseteq G$ is a subgraph and ${\Gamma}_H$ is a
planar orthogonal drawing of H. We show that the existence of an orthogonal
drawing ${\Gamma}_G$ of $G$ that extends ${\Gamma}_H$ can be tested in linear
time. If such a drawing exists, then there also is one that uses $O(|V(H)|)$
bends per edge. On the other hand, we show that it is NP-complete to find an
extension that minimizes the number of bends or has a fixed number of bends per
edge.
