  We prove an exact triangle relating knot instanton Floer homology to the
instanton homology of surgeries along the knot. To the author's knowledge, this
is the first such result in instanton homology with integer coefficients and
has no analogue in Heegaard Floer homology. To illustrate the latter claim, we
derive as a consequence of this triangle, building on previous computations in
the literature, that the Poincar\'e Homology Sphere is not an instanton
$L$-space with $\mathbb{Z}/2$-coefficients.
