In this talk I will discuss our recent theoretical and experimental results for spin-wave dispersions in n-doped semiconductor quantum wells subject to in-plane magnetic fields. Our particular focus is on the interplay between spin-orbit coupling and electronic many-body effects. Rashba and Dresselhaus spin-orbit coupling induces a wavevector-dependent spin splitting in the conduction bands. The spin waves hence travel through a spin-orbit twisted medium, which leads to interesting new ways of controlling the direction and group velocity of the spin waves. Due to the absence of spin-rotation invariance, Larmor's theorem is broken. For the special case of equal-strength Rashba and Dresselhaus spin-orbit coupling, a new exact many-body result is found, which we call the spin helix Larmor mode.