Ouch, my sympathy on the "-itis" you're fighting. I've moved away from the 6.1 classic this year, but I went in the direction of heavier and more flexible frames. The Wilson has never hurt my arm, but the Prostaff has so much gas over spin for me that I can't sustain a singles rally as effectively with it. The Diablo and NXG options I think are worth a look - the mids may swing heavier than you want - but the nBlade is definately worth a look given the reception it's gotten lately. The Prince O3 Hybrid Hornet is quite user friendly for a middleweight and has also made a lot of friends in case you see one on a wall of demos. My $.02... (GOOD list of options from T.B.G.)
Oh, one lesson I've learned on strings: although the Prostaffs seem to demand being strung right up to 65# or so, other racquets may actually require rather loose tension to work right. Higher tension doesn't guarantee better feel or control.
Healthy and speedy recovery to you.