Dear Doctor: I read that you can use your own stem cells to rejuvenate worn-out knees. Does this really work?

Dear Reader: "Worn out" is a good way to term what happens to the knee joint with prolonged use. Let's look at how this happens, starting with cartilage.

The lower portion of the knee joint (at the tibia) contains shock absorbers -- called menisci -- made of cartilage. You have one on the inner portion and another on the outer portion of each knee. The upper portion of the knee joint (at the femur) is lined with cartilage as well. All of this cartilage helps protect the bones at the joint -- but it doesn't heal or regenerate well due to limited blood supply. When severe, worn cartilage leads to arthritis of the knee. In knee X-rays of people over the age of 60, 37 percent have shown evidence of arthritis of the knees.

The intriguing thing about stem cells is that they have the ability to become any type of cell that the body needs. The cells used for stem cell injections in the knees are called mesenchymal stem cells, and they can differentiate into bone, fat or cartilage cells. These stem cells can come from the fat cells of your body, from your bone marrow or from the inner lining of your knee joint; they're then replicated in the laboratory and injected into the knee joint.

Here's what the research shows so far ...

In a 2013 study, 32 patients with meniscal tears of the knee were injected with a combination of stem cells, platelet-rich plasma and hyaluronic acid. The study reported improved symptoms and even MRI evidence of meniscal cartilage regeneration.

In a 2014 study, 55 patients who had surgery for meniscal tears of the knees were separated into three groups, with two of the groups receiving stem cell injections. Researchers found that, after six weeks, pain had decreased substantially in the two groups that received stem cell injections and that the decrease was even greater at one and two years after the injection.

In a 2017 study in the British Journal of Sports Medicine, researchers analyzed six studies that used stem cells for osteoarthritis of the knees. In five of the studies, stem cells were given after surgery to the knee; in the other study, stem cells from a donor were administered without surgery. All the studies showed reduced pain and improved knee function. Further, in three of the four trials, MRIs corroborated the cartilage improvements. However, the authors noted, five of the six studies were of such poor methodology that an overall conclusion about the stem cells' effectiveness could not be made.

In all these studies, the most common side effect was knee swelling and stiffness, which improved over time.

There may be benefit to stem cell injections for cartilage loss of the knees, but more data are needed, especially in those who aren't having surgery of the knee. I'd also like to see more data on this type of therapy as a preventive measure for younger patients -- before their knees are worn out.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Is there anything I can do to keep my doctor from interrupting me? He's a really nice man, and I know he's busy, but I never get to share all of my concerns or have my questions answered before the visit is over.

Dear Reader: You've brought up an issue that's getting a lot more attention than it once did, and one that doctors in all specialties are actively working to address. We do have some specific strategies, but first, allow us to nerd out a bit.

A study on this subject with a statistic that often gets cited -- that on average, a patient speaks for about 17 seconds before the physician cuts in -- was conducted all the way back in 1984. Subsequent studies, which used larger sample sizes, highlighted the same challenge. These days, the amount of time a patient gets to speak uninterrupted has edged up about 50 percent. But considering that's now in the neighborhood of 25 seconds, it doesn't seem like much of an improvement.

So what can you do?

Begin your appointment with a mission statement. Politely tell your doctor that, before he or she responds, you would like the chance to lay out all your questions and concerns. This may sound like you're asking permission for an interminable monologue. However, in studies where patients were allowed to speak without interruption, it took them between 90 seconds and two minutes to present their information.

So you've said your piece. Now, it's your turn to help things move smoothly.

Begin by listing the things you want the doctor to address. Perhaps you have a specific medical issue, and you also want general advice about another topic or two. Make that clear. This will let your doctor mentally prepare for how best to spend the remaining time in your appointment.

If you do have a specific medical issue, be prepared with a concise and fact-filled narrative. Tell him or her when the symptoms began, how and when they changed or escalated, and what they feel like. A burning sensation, a stabbing pain, an ache that occurs when you move a certain way -- all is useful diagnostic information.

When you're finished speaking and are ready to listen, let your doctor know. And when he or she begins to answer, pay attention. Take notes. If something that is said needs follow-up questions, make a note of it. As the visit ends, use your notes to quickly summarize the information and instructions. This way, you both know you're on the same page.

Sometimes you do wind up with follow-up questions once the appointment ends. Here at UCLA we have an electronic communications portal that our patients can use to reach us. Perhaps your medical provider has something similar. Ask for a few minutes with a nurse or physician's assistant. And don't be afraid to make another appointment if you feel that's what you need.

Life in a doctor's office moves quickly these days. We understand that speaking up can be uncomfortable for you (and perhaps even for your doctor). But when you do, we believe both of you will come away with a greater sense of satisfaction.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I was diagnosed with myasthenia gravis in 2014 after years of trying to find an answer to my symptoms. The disease is so difficult to diagnose that I'm afraid others have been searching as well, but without answers. Could you shed some light on this disease?

Dear Reader: To understand myasthenia gravis, you have to first understand how the nerves of your body make your muscles contract. Nerves that control muscle contraction attach to the muscle in an area called the neuromuscular junction. There, a nerve releases the neurotransmitter acetylcholine, which then binds to a receptor in the muscle. The binding to the receptor causes a cascade of changes that leads to the contraction of a muscle.

In the majority of people with myasthenia gravis, antibodies attack the acetylcholine receptor at the neuromuscular junction. The attack damages, and can even destroy, these receptors to such an extent that nerve impulses can't cause muscular contraction. Some people have other antibodies that impair the actual formation of the receptor. The thymus gland, a lymphatic gland behind the breastbone, is often the source of the antibodies that lead to myasthenia.

The telltale sign of myasthenia gravis is muscle weakness and muscle fatigue with recurrent muscle use. Patients can have no signs of muscle weakness in the morning, but with repetitive contraction of muscles during the day, the muscles get fatigued and weak. About 50 percent of the time, the muscles of the eye are affected, leading to drooping of the upper eyelid and sometimes double vision. Myasthenia gravis can also cause weakness of the jaw, leading to difficulty chewing or closing the mouth, and weakness of the facial muscles, interfering with facial expressions.

Elsewhere in the body, the disease can affect the muscles of the neck, making it difficult for people to hold up their head, and the upper arms and legs (arms are more often affected than legs). Sometimes, the disease also affects movements of the wrists, fingers and ankles. When severe, myasthenia gravis can impact the respiratory muscles, causing difficulty breathing, and even the muscles involved with swallowing.

Sudden severe weakness from the disease, called myasthenic crisis, can be precipitated by infections, antibiotics and some heart medications. In these situations, breathing difficulties lead to hospitalization and sometimes ventilator use.

Myasthenia is a rare disease, which may be why some doctors don't recognize the symptoms. Each year, myasthenia is diagnosed in eight to 10 out of 1 million people; within the United States, about one out of every 5,000 people are affected. The disease can be diagnosed by blood tests that detect antibodies to the acetylcholine receptor or antibodies to the enzyme that helps form the receptor, called MuSK. Another way to diagnose myasthenia is through repetitive nerve stimulation tests that evaluate whether muscle strength declines.

Muscle weakness can be treated with a medication that increases the amount of acetylcholine at the receptor or through drugs that dampen the immune system in order to limit the receptor-attacking antibodies. In younger patients with enlarged thymus glands, removal of the gland can cure myasthenia. One comforting fact is that in the majority of patients dealing with myasthenia, the symptoms go away with time.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)