Botox injections
Arthritis Today presents an American College of Rheumatology Report: Intra-articular Botulinum Toxin Type A May Offer Joint Pain Relief to Osteoarthritis Sufferers.
Injections of intra-articular neurotoxins may offer relief from severe knee pain for osteoarthritis patients who are not candidates for joint reconstruction, according to research presented at the 2006 American College of Rheumatology Annual Scientific Meeting in Washington, DC.
For thousands of knee pain sufferers, arthroplasty is the solution of choice. This surgical replacement or reconstruction of the diseased joint restores function improves range of motion and decreases pain. However, for those who are too young, too old or too frail for such surgery, neurotoxins, which target the pain nerves within the joint, delivered to the knee joint cavity may provide sustained pain relief.
To determine the potential benefits of injecting a neurotoxin directly into the knee joint cavity, researchers embarked on a six-month study of Intra-articular Botulinum Toxin Type A (IA/BoNT/A) versus placebo in 37 patients with moderate to severe refractory knee pain due to osteoarthritis. IA/BoNT/A, otherwise known as Botox, disrupts pain nerve function and may reduce nerve-related inflammation.
The 36 men and one woman participating received either 100 units of IA/BoNT/A with lidocaine (a short-acting anesthetic) or a saline placebo with lidocaine. Double-blind assessments were scheduled for baseline, 1-month, 3-month and 6-month time points. Primary outcomes to be measured at each milestone include self-reported total pain score and a physical function score. A walking pain score, day pain severity, night pain severity and an observed timed-stands test were also measured.
At the 1-month interim analysis of this study, two placebo patients had dropped out from lack of benefit. Of the 18 patients in the severe pain group (half on IA/BoNT/A and half on placebo), there was a significant decrease in pain and improvement in physical function for those who received the botulinum toxin injection. Those injected with the placebo experienced minimal improvement. In the moderate pain group, neither injection produced significant changes in the primary outcome measures. Interestingly, in the moderate pain group, there was a 25% reduction in daytime pain severity after the placebo injections.
Three-month measurements will be completed by January of 2007, and the trial is scheduled for completion in August of 2007. To date, however, researchers point to clinically and statistically significant decreases in severe osteoarthritis knee pain and improvements in physical function.
“If this novel approach to local treatment for refractory join pain continues to prove beneficial, it offers a very welcome solution for fragile patients,” explains Maren L. Mahowald, MD, Rheumatology Section Chief at the Minneapolis VA Medical Center, Professor of Medicine at the University of Minnesota, Minneapolis, Minnesota, and principal investigator in the study. “Local joint treatment with injection could replace oral medications that carry the risk of systemic side effects, and may negate or delay the need for joint surgery. Much more research will be needed to determine the most effective and safe dose of toxin for the joint injections and the most appropriate dosing intervals.
