Is Surgery Only Way Out For Subchondral Cyst With Pain And Swelling?

47 y/o female, severe sprain 10 yrs ago, chondral damage no fx; arthro cleaned out loose bits, subsequent infection and 2d arthro w/irrigation, etc. now has chronic pain, swelling, MRI shows degen, subchondral cyst with absence of cartilage, loss of tib-talus space and supposedly a spur; surg has been recommended what do you think?