Keeping Hands in Working Order

Arthritis Foundation-funded researcher seeks better treatment for osteoarthritis at the base of the thumb

Arthritis Today—March 4, 2013

Hear the word "arthritis" and you may automatically think of hips or knees. Osteoarthritis (OA) at the base of the thumb is just as common, but has not been studied as much. In fact, when Lisa Mandl, MD, MPH, a rheumatologist at Hospital for Special Surgery in New York City, first started seeing patients in the clinic, she was surprised at the number of people - mostly older women - who came to her complaining of severe pain at the base of the thumb.

Even though the patients had sought relief from cortisone injections, splints, physical therapy and non-steroidal anti-inflammatory medications, they were still experiencing pain severe enough to wake them at night. The only option left was surgical repair of the joint, an option most of Dr. Mandl’s patients were not ready to accept.

Dr. Mandl set out to learn everything she could about carpometacarpal OA. She read everything in the medical literature only to learn that not much is known about this type of arthritis.

The carpometacarpal (CMC) joint is at the base of the thumb, where the thumb attaches to the hand. Like arthritis in the hip or knee, the pain comes when the cartilage wears away so much that bone rubs against bone. As with OA of the knee and hip, CMC OA is more common in women than men. By age 80, up to 80 percent of women are affected.

CMC OA interferes with daily activities in kitchen, around house, in people who do keyboard work, or assembly work or need to use power tools.

Thumbs Up

Dr. Mandl wondered whether an injectable medication called Synvisc, used for knee OA, would work in the thumb.  The active chemical, hyaluronan, also called hyaluronic acid, is present in joint fluid. The ends of joints are capped with cartilage and a piece of cartilage also sits between joints as a cushion. Hyaluronic acid lubricates the joint, like motor oil, to keep cartilage, gliding in a fluid motion.

Some researchers had already looked at hyaluronan injections for CMC OA, with mixed results. OA is a difficult disease to study because people have good days and bad days, even without treatment. "Showing a real benefit of medication can be difficult, but it is worth trying to see, in a definitive way, if it might help these patients - because they do not have many options," says Dr. Mandl.

Currently, the U.S. Food and Drug Administration only approves hyaluronan for the knee. Injections can provide some pain relief for four to six months. The drug is given by local injection. Dr. Mandl found the idea of a local injection appealing for the thumb, especially because some people – people over age 65, in particular - can't tolerate non-steroidal medications, especially if they have gastrointestinal problems such as ulcers.

Dr. Mandl received funding from the Arthritis Foundation, the National Institutes of Health and Genzyme, which donated the hyaluronan, for a large clinical trial. She is nearly finished with recruitment and will begin analyzing the results soon.

Studying hand OA, such as the type of work Dr. Mandl is doing, will help researchers understand the progression of OA in other joints. Studying CMC in a non-weight bearing joint may help researchers identify some of the other risk factors that are not related to weight, such as genetics.

Read the full story at arthritistoday.org.

Read the news release on the study's results at Expensive Arthritis Treatment No Better Than Steroid Therapy.