DEAR DR. ROACH: My wife is suffering from a failed back surgery that was caused by a neurosurgeon. The operation was four years ago, and she also had a spine stimulator that was implanted three years ago. Her pain management doctor said that she’ll get progressively worse as current medical care hasn’t improved for this condition. She’s currently consuming the maximum dose of pain medication. To your knowledge, is there any “light at the end of the tunnel” for patients with chronic arachnoiditis?

• B.B.

ANSWER: Persistent spinal pain after surgery (PSPS), which was formerly called “failed back surgery syndrome,” is a difficult diagnosis for patients as the treatments aren’t optimal. The major symptoms are pain, abnormal sensations and sometimes weakness — most commonly in the lower back and legs. An MRI scan usually confirms the diagnosis.

Sometimes surgery is attempted, but it can make symptoms worse. So, it’s only suggested for some individuals. Pain medications are routinely used — often at very high doses, as seems to be the case for your wife. Spinal cord stimulators and epidural injections can also be beneficial for some people. Physical therapy can be of great benefit.

I wouldn’t say that it’s definite that people with PSPS and arachnoiditis are destined to get progressively worse. Long-term studies (up to 21 years) have shown that most people have a stable course, although symptoms can fluctuate with some days being better and others being worse.

I’m very sorry for both you and your wife, but I don’t know of any dramatic improvements that are on the horizon for this difficult-to-treat condition.

DEAR DR. ROACH: I’m 77, and I was diagnosed with osteoarthritis in my right knee, which is almost bone-on-bone on one side. (I guess this is from a lot of sports over the years.) Anyway, I’ve seen a specialist who gave me a steroid injection with a local anesthetic. He said that people usually do this a few times (at least three months apart), then get a knee replacement.

Is there a procedure out there that would just replace the worn-out pads instead of the entire knee joint? If not, how come? I should’ve asked the doctor but didn’t think of it until later.

• M.O.

ANSWER: Many people think osteoarthritis comes from exercise, but this doesn’t actually seem to be the case. It can be triggered by severe trauma, but regular exercise like running doesn’t make osteoarthritis more likely. In fact, exercise remains one of the most important treatments to maintain good function and help with pain.

Knee replacement surgery is the definitive treatment for osteoarthritis. If you could design a new pad for the knee, you could improve many people’s lives (and become very rich). But so far, all attempts to do so, whether through stem cells, cultured cells or prosthetics, have been unsuccessful.