Back Pain and leg weakness

I have Chondromalcia of the right knee joint. As a teenager I had two surgerys on my knee, one was to remove part of the patella that had broken off. As a result I have a very weak knee with arthritis. This in turn has thrown my back out. About two years ago I saw a chiropractor. He had pointed out that I was carrying 40 more lbs. of weight on my left leg than on my right. At that time I was in a lot of pain. The chiropractor helped but due to cost, I was unable to finish my treatment. Since then I have had a baby which I gained about 30 pounds with the pregnancy and now cannot loose any of the weight. during and after my pregany I have experienced agonizing hip pain and lower back pain. I have been in pain and to the point where I can barely walk. I also have had increasing weakness in my left leg. Recently the weakness has been stronger and comes and goes, but at some points it feels as though my leg will give out. The chiropractor said I have Swayback and some arthrits? Not sure what this means, but the x-rays showed my spine very much in trouble. I have been to the ortho about my knee....they suggested exercise to help make my knee stronger, but I can barely do so because of my back. Could I have a herniated disk? Arthritis of the spine? What do you suggest I do?  

[Titantic]

ditto, ditto . Have no knee problems, but trust e, go see an orthopedic and have an MRI done. You have the very same system I did with the exception
of the knee.My left leg was sooooo weak!   I carried all of my weight on my right leg.
and had shooting pains, or (stingers) from the buttock down through my left thigh.Bingo! Had MRI and L5 was herniated. I have had 2 surgerys so far on it, due do re-injurying.As a matter of fact, just had the surgery the 5th f this month.The first surgery was immediate relief.But this second was not as pain reliefing as the 1st. Doc said to give myself at least 8 more weeks and to do my excercises.I am no doc, but I would suggest an MRI.