Cool log Sharla CC. I know how it feels to have injuries, I'm currently off training while a Physio is trying to sort out my harmstring.

One comment I'll make about your knee, perhaps you already know this, when you're doing squats ensure your knee is directly above your ankle/foot (i.e arse further back) with your weight on the heel rather than leaning forward with the weight on the ball of your foot, this should put less pressure on the joint. I only mentioned it since this is harder to do when you do one legged squats.

Anyways, good luck with the back as well.