Thanks to both of you for your responses, which are re-assuring. My concern stems from having had tendon-repair surgery on my ankle last year, which led to a bout of Complex Regional Pain Syndrome in immediate aftermath. Fortunately a course of Lyrica cleared up the shiny, red, sweaty and painful left foot. CPRS and SFN, as you know, are closely associated; it occurred to me later that perhaps my SFN, which I've suffered since 2006, and has worsened in recent years, may have contributed to the CPRS in my foot, given the vulnerability of my distal nerves. I've also discovered since then that the agents used in nerve blocks are neurotoxic. My TKR will be first in line, though it hasn't yet been scheduled. Thanks so very much again.