Dear Doctor: I’m a 66-year-old man whose right knee really hurts from arthritis. My sister keeps talking about something called prolotherapy. What is it, and can it help?

Dear Reader: Prolotherapy is an injection-based approach to treating pain in the soft tissues of the joint. Specifically, a small amount of a liquid irritant is introduced at the site where a tendon or ligament attaches to the bone. The idea is that the irritant will set off a localized inflammation reaction, which will then trigger the release of growth factors that promote the healing of soft tissues.

The roots of prolotherapy date back to the ancient Greeks, who believed that deliberately causing inflammation in a certain area of the body could stimulate the tissues to repair themselves. In the 1930s and 1940s, several physicians expanded on the concept. They experimented with various solutions and developed techniques -- sometimes referred to as “needle surgery” -- to target connective tissue in the joints.

Today, prolotherapy injections typically consist of sugar- or salt-based solutions to which a local anesthetic, such as lidocaine, is added. Patients seek the treatment to help with joint pain and stiffness resulting from injury, overuse or inflammatory conditions such as arthritis and degenerative disc disease. Areas of the body targeted by the practice include the knees, back, hips, ankles, shoulders and hands.

Treatment protocols usually consist of a series of three to eight injections given over weeks or months, depending on the specific case. The injections can be moderately painful, and patients often use Tylenol or stronger medications to manage localized aches and tenderness. Patients are advised to limit activity for several days after each injection, and they may be asked to supplement the therapy with specific exercises that focus on range of motion.

Since creating inflammation is the point of prolotherapy, the use of NSAIDs, or non-steroidal anti-inflammatories, to address the resulting pain and discomfort is not recommended. Possible side effects of the procedure include bleeding, bruising or swelling at the injection site. These can last for a week or more. Allergic reactions to the injected solution, infection and nerve damage are possible, but rare.

Does prolotherapy work? In some case studies, patients report improvement in pain and strength in the affected areas. But studies of the treatment have yielded mixed results. Some have argued that the studies showing benefit have been too small and not scientifically rigorous. The one area of agreement appears to be the need for large and scientifically rigorous studies.

Although prolotherapy is gaining in popularity, the National Institutes of Health identify it as a complementary and alternative medical treatment. And since it’s considered an experimental therapy, many insurance companies won’t cover it. Costs can range from $400 to $1,000 per treatment, depending on the provider.

As with all alternative therapies, we think it’s wise for you to check with your doctor to see whether prolotherapy may be helpful for you.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Hello, dear readers, and welcome back to our monthly letters column. We’re happy to report that you’ve been busy correspondents, so onward to your letters.

-- A reader from Pennsylvania asked for the name of a condition in which eating food causes one’s nose to begin running. This is a type of nonallergic rhinitis, which means the inflammation of the nasal passages is not related to allergies. In this case, the specific name for the condition is gustatory rhinitis, and it’s often triggered by hot or spicy foods. But as is the case with our reader, it can also occur when eating any kind of food. The good news is that ipratropium bromide, a prescription nasal spray sold as Atrovent, can be effective when used before eating.

-- In response to a column about hemorrhoids, a reader from Indiana shares that she and her husband have had success preventing hemorrhoids by using a supplement called rutin. A plant pigment and natural antioxidant, rutin is contained in many fruits and vegetables. Rutin is believed to aid in circulation, and studies show it can improve blood cholesterol. While it is safe to eat natural sources of rutin -- such as apples, citrus fruit, asparagus and green tea -- rutin supplements can sometimes be associated with unwelcome side effects, such as headache, stomach upset and heart arrhythmias. Always check with your health care provider before using any supplements. Many are not regulated, and some can have unexpected drug interactions.

-- A reader in Indiana wonders about the safety of public grill grates at campgrounds. Some of these grates “have a great deal of rust on them. There is no way you would be able to remove it all,” he wrote. “Most people just dump in the charcoal and starting grilling. What about all that rust that surely gets on the food being cooked?”

Rust, which is iron oxide, is harmless in small quantities. That said, if the grill that you’re using is damaged to the point that it’s crumbling, it’s wise to steer clear. However, if the grill has visible rust but isn’t giving off particles, and as long as you’re not using it on a regular basis, the small amount of rust that may get transferred to the food is benign.

-- And finally, a reader from North Dakota requests that we write a column about how to reduce blood pressure. It’s an important issue, and we will gladly comply -- be on the lookout for upcoming information. Meanwhile, she shares an unexpected technique she uses when her own BP climbs a bit too high:

“We learned the polka in gym class when I was in school,” she wrote. “Now, when I want to get my blood pressure down, I put on a polka CD and dance and clap and shake myself for about 15 minutes, and the blood pressure reading goes way down.”

We thank you, as always, for reading the column and taking the time to write to us. We look forward to hearing from you, and will see you again in the letters column next month.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: How long should a bruise last? I broke my fibula nearly nine months ago, but I still have a yellowish discoloration on my shin, above the fracture. What could it be? My doctor is unconcerned.

Dear Reader: When you get a bruise, or contusion, it means that the small blood vessels beneath the skin are damaged and leaking blood. This can occur as the result of a physical injury, certain nutritional deficiencies or a medical condition, such as end-stage kidney disease, leukemia, bleeding disorders and some cancers. When blood seeps into the soft tissues beneath the skin, it causes the dark coloration that we recognize as a bruise.

As a bruise heals, the body breaks down and reabsorbs the blood and lymph fluid released by the injury. During this process, the bruise goes through an array of varied and vivid colors, including bluish-purple, green, yellow and brown. How long it takes for the visible effects of the bruise to vanish depends on the location and the extent of the injury, the person’s age and their skin tone. People with pale skin tend to show bruises more readily than those with darker pigmentation, as do the elderly, whose skin becomes thinner with age. In most cases, a bruise will take from two to four weeks to heal completely.

In your case, the injury took place in the fibula, which is the smaller of the two bones of the lower leg. The fibula is long and thin and doesn’t bear much weight. Instead, its job is to help stabilize the tibia, or shinbone, as well as the ankle and the muscles of the lower leg. There are several types of fibula fractures, some of which could result in significant bruising.

The fact that visible bruising persists nine months after you broke your leg, and isn’t associated with any other symptoms, is consistent with something known as hemosiderin staining. Hemosiderin is a byproduct of the breakdown of red blood cells, which contain iron. It’s a protein compound with a brownish-yellow color and acts as a storage system for the iron left behind by the damaged red blood cells. In hemosiderin staining, the compound accumulates beneath the skin and becomes visible. Trauma, such as breaking a bone, is among the potential causes of hemosiderin staining.

You mentioned in your letter that your physician doesn’t believe the persistent color on your shin is a symptom of anything serious. We think it would be a good idea to check whether he or she agrees that hemosiderin staining may indeed be the cause. If the answer is yes, and if the condition bothers you, you have several treatment options. Topical creams can reduce the degree of pigmentation, or lighten the color. If the goal is to minimize the discoloration as much as possible, you can explore laser therapy. As with tattoo removal, it may require multiple sessions to see results.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)