Hand OA: Testing Hand Injections
Researcher seeks better treatment for osteoarthritis at the base of the thumb.
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.
“Hand OA is, to some extent, overlooked because we don’t walk on our hands,” says Jeffrey Katz, MD, professor of Medicine and Orthopedic Surgery at Brigham and Women's Hospital, one of Dr. Mandl’s longtime mentors.
Although knee and hip OA can literally knock people off their feet, the disability from hand problems is “more subtle but it’s very striking,” says Dr. Katz.
Dr. Mandl says she has seen patients who are otherwise healthy, but their terrible thumb pain is ruining their lives. “It struck me how they’d waited to retire and play with the grandkids, and then couldn’t do it.”
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.
Dr. Katz expects the prevalence of hand OA to only worsen as the older population stays more active and stays in the workplace longer. “It’s one of those older worker problems,” he explains. “As the workplace ages, we need to develop work tasks and equipment with the understanding that more workers will have this problem.”
Dr. Mandl wondered whether an injectible 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.
Patients with CMC OA were divided into three treatment groups. One group received a placebo injection; another group received an injection of corticosteroid, and the third group will receive hyaluronan. Dr. Mandl will follow up at six months to determine whether the patients’ pain is better. The team will also test for any improvement in how well the hand works. At the study’s completion, all participants will have the option of receiving a free injection of hyaluronan.
Her greatest challenge was recruiting patients, which delayed the project at the onset. Patients were more apt to join once Dr. Mandl offered the guaranteed injection once the study is completed.
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.
“We’re going to learn something that will inform practice and that will help us better understand the disease,” says Dr. Katz.