Radiotherapy of Finger Joints for Osteoarthritis Found Effective

Larry Schuster

June 26, 2003

June 26, 2003 (New Orleans) — Researchers reported the first study suggesting the clinical value of internal radiotherapy of the finger joints affected by osteoarthritis.

A treatment that has been used successfully in Europe for more than 40 years for rheumatoid arthritis, radiosynoviorthesis resulted in long-term clinical success in about two thirds of joints in a study of 29 patients and 53 joints.

Patients achieved significant pain relief in about two thirds of the treated joints with a mean follow-up of 3.5 years, said Willm Uwe Kampen, MD, assistant medical director at the Clinic of Nuclear Medicine, University-Hospital Schleswig-Holstein, in Kiel, Germany. Dr. Kampen presented the results here at the 50th annual meeting of the Society of Nuclear Medicine.

"This is only slightly less than the results known in rheumatoid arthritis," Dr. Kampen and colleagues reported in their abstract, and the procedure "should be considered as a treatment option also in cases of digital joint osteoarthritis."

The patients often are pain-free or have significant pain relief for several years before coming back for a follow-up treatment, Dr. Kampen told Medscape. But relief is not instant; the radiopharmaceutical colloidal erbium-169-citrate is slow acting, taking about six months to treat the damaged cartilage surrounding the joint. And then the cartilage regenerates.

"They've had pain for 10 years, so what's six months," Dr. Kampen said in the interview.

Not all joints responded. The thumb base joints did best, with 13 of 15 joints improved, he said. Twelve of 17 proximal interphalangeal joints improved. Of 15 distal interphalangeal joints, eight improved, and one of four metacarpophalangeal joints had sufficient pain relief.

As described in their abstract, the researchers report that local synovitis was proven by an elevated blood-pool pattern in pretherapeutic three-phase bone scanning. The clinical success was evaluated 10 to 70 months after treatment using a standardized questionnaire. A 10-step pain score was used for classification of the patients' complaints during daily manual activities, such as tying shoe laces, writing, or shaking hands. The joints treated by radiosynoviorthesis were evaluated in a 4-step scoring system, comparing them with the scores prior to therapy.

At an SNM-sponsored press briefing, Bruce Line, MD, vice chair for general clinical specialties of SNM, and director of the Division of Nuclear Medicine at the University of Maryland, said that during radiosynoviorthesis, a small needle injects radioactive fluid into the joint. Colloidal radiation is emitted within the joint capsule, where it's trapped.

"It's trapped there because it's a colloid. It can't get out of the area," Dr. Line said. "And it gives radiation therapy to the lining of the joint, causing a bit of fibrosis of the area of treatment, which leads to reduced inflammation and eventual pain relief."

He noted that patients are usually treated with acetaminophen to relieve the pain in mild to moderate osteoarthritis, but the drug often does not reduce inflammation. As the pain increases, nonsteroidal anti-inflammatory drugs help reduce the pain and swelling and decrease stiffness, but they do not prevent further joint damage.

As the natural progression of the disease moves forward, causing severe pain and inflammation, cortical steroids can be injected directly into the affected joint. However, cortical steroids tend to weaken the cartilage and remove bone minerals, resulting in further joint weakness.

"So, in this setting, where we see a number of patients who have advanced disease, changes in the joint, we're looking for other ways to help manage that pain and treat the patient's problem," Dr. Line said. "The procedure may provide an alternative to current treatments used in the U.S. forsome patients with severe osteoarthritis. And it's certainly important, because osteoarthritis is the most common type of arthritis, affecting almost 16 million men and women in the U.S., and...most people over the age of 60 are affected."

Dr. Kampen said that nearly all people aged 70 years and older have osteoarthritis, and about half have osteoarthritis in some finger joints. In many cases, the joint disease is not symptomatic. But many patients come too late in the process, after significant damage has already occurred to the joint. Even so, radiosynoviorthesis should not be a first-line therapy, either, he told Medscape. Because the procedure is invasive, it does carry a risk, albeit very small, he said.

As a referral center for northern Germany, Dr. Kampen's center performs 20,000 radiosynoviorthesis procedures a year on all joints for rheumatoid arthritis and osteoarthritis. The procedure is not currently approved for use in the U.S.

SNM 50th Annual Meeting: Abstract 489. Presented June 24, 2003.

Reviewed by Gary D. Vogin, MD

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