I am 38 years old and have had 2 arthiscopic surgeries and in April had a uni-spacer put into my knee. The unispacer isn't working (I am still in pain & my right leg will not go straight). The second arthiscopic surgery was 5 months after the uni-spacer was installed to remove scar tissue, in hopes that w/o the scar tissue my leg would go straight....it didn't. I am now also experiencing pain in my left knee as well as my lower back. My doctor has now scheduled me for a uni-compartmental medial meniscus (partial) knee replacement. I currently drive a tractor trailer, has anyone had one at this young age and been able to go back to work at a manual labor job like mine? Thanks for any advise you can give.