what is the nature of your hip knee and ankle problems? and did they start before your back problems?.
One of the problems for doctors when they encounter patients with widespread musculoskeletal problems is figuring out which one is causing which symptoms.
Also its possible that your back caused your hip knee and ankle problems or it could be the other way around.
Any injury to your back or leg that would cause your gait to become abnormal would cause abnormal forces across the joints in your back, hips, and legs, and possibly your neck this can accelerate the degenerative changes that occur with age.
Its also possible that there are separate reasons for your numerous injuries.
You have disc problems at three levels with the possibility of nerve compression at two of these levels you also have arthritis in the small facet joints at the rear of your vertebra at the L4-L5 level.
The bone structure of your bottom vertebra is abnormal this would have occoured somtime during its developement when you were younger it could be the cause of your problems.
Good luck Mexia