As MKV is not an encoding but a container I can't guess where you are in the learning cycle of video formats, containers and encodings.
Again, since MKV is a container of any of the dozens of encoding methods, you would never find an editor that could claim it would edit the video in the MKV unless they were being short on words and sidestepping the real discussion.
Until we know the encoding inside the MKV "box" my answer is no.
I'm looking for a fast, easy-to-use editor (Win 7) that can read/write MP4 and MKV recordings. Video Redo was recommended to me, but I'm not sure which version to get, or if there are alternatives I should check out.