Another Silky fan here, and I'm two-yrs retired from commercial work. I believe it's a Silky Zubat that I use. I had a machinist sharpen it for me once (he did all my other sharpening, chipper knives, etc.) but the results were unimpressive. So I got used to replacing the blade when necessary. Buying Silky seems expensive at first, but there's just no comparison when it comes to performance.
I have two manual pole saws that I use a lot. One is a Stihl that's about 21' long--I use it only when I need that long reach, because the Stihl blade cuts like a dog when compared to my 15' adjustable saw with Silky blade. This was originally a Corona saw, but it's blade was unimpressive and dulled quickly so I fixed the saw to mount a silky blade that I've used ever since. Probably replaced the blade 2--3 times since, the first time when my helper got the saw pinched and pushed it until the blade broke. (He was such a good employee in every other way, I couldn't hold it against him.) But I enjoy using that outfit.
BTW, I'm 4 months out from total knee replacement. Wow, it's a long process. But I'm doing well. Went out Tuesday and loaded an entire elm tree (cut up, but still some large, heavy chunks) on my pickup and trailer. Then came home, unloaded and did some more cutting. First real work since Nov., and it was really nice to be back at it. Hope you're doing well with your knee.