Hope you hit the hatch/emergence. Found skwalas a few times last April, then I lucked out and caught the tail end of the skwalas and start of the salmonflies on the same day last May; the fish were very interested in skwala flies until the big orange (actually rusty) bugs showed. One thing I found - although there werern't a lot of bugs out (never did see a skwala in the water and only a few flying), if there was any sign of them, even just shucks on the rocks and bushes, the fish were usually willing to take a dry.
Best of luck with the knee.

Regards,
Scott