So I have been these boards for quite some time and was going to save you money and suggest you pull out your old TTW, did not realize you had elbow problems with this rkt.
I also play around with a lot of different rkts and was looking into my old collection and pulled out the bumble bee version of the C 10 and had a competetive match last night with it, served well, returned well, volleyed well, this one a bit heavy comes in at 12.6 ounces so whipping up low balls that required alot of wrist action suffered, probably my fault not the best technique or footwork here. So the new C10 with SW in 226 should be great. For what its worth Chris gave an excellent review of such and I believe he gives an honest critique. With your knee surgery I presume the recomendation for dubs over singles was because of decreased mobility, so if so, you want a rkt with good sweet spot and decent power as your footwork will not always be excellent and a SW in 220 to 225 range. I use TWU to assess sweet spot, SW and the section on shot distance, this spot debunks lots of here say on these boards and can give you a scientific starting point to demo some rkts