Efficacy of Intra-Articular Botulinum Toxin Type A in Painful Knee Osteoarthritis: A Pilot Study
ABSTRACT To evaluate the efficacy and safety of botulinum toxin type A (BoNT-A) injected intra-articularly in 60 subjects with moderate pain and functional impairment secondary to knee osteoarthritis. The study investigators hypothesized that intra-articular BoNT-A would result in statistically significant improvements in pain and function at 8 weeks.
Double-blind, randomized, single tertiary care academic medical center trial with 6-month follow-up.
Sixty patients aged 40 years or older with painful osteoarthritis of the knee who had failed physical therapy, medications, and/or injection therapy presenting to the musculoskeletal or orthopedic outpatient clinics at a large tertiary care medical institution. All 60 patients completed 8-week follow-up, but only 32 patients completed the 26-week follow-up.
Subjects were randomized to receive a single injection of corticosteroid, low-dose BoNT-A (100 units), or high-dose BoNT-A (200 units). Outcome measures were compared at baseline, 4, 8, 12, and 26 weeks after injection.
The primary outcome measure was pain visual analog scale (VAS) at 8 weeks. Secondary outcome measures included Western Ontario McMaster Arthritis Index, Short Form-36 scores, patient global assessment, 40-meter timed walk, and adverse effects.
The primary end point was pain VAS score at 8 weeks, which decreased within each group but only reached statistical significance in the low-dose BoNT-A group. In the intra-articular corticosteroid group, VAS decreased from 6.4 +/- 1.8 to 5.4 +/- 2.3 (P = .15); for low-dose BoNT-A, from 6.6. +/- 1.9 to 4.5 +/- 2.2 (P = .01); and for high-dose BoNT-A, from 6.6 +/- 1.4 to 5.9 +/- 2.4 (P = .15). All groups showed statistically significant improvements in Western Ontario McMaster Arthritis Index scores (pain, stiffness, function) at 8 weeks. No serious adverse events were noted in any group.
This pilot study supports a possible role for BoNT-A as a treatment option for symptomatic knee osteoarthritis; however, larger double-blind randomized studies are needed to determine whether BoNT-A is more effective than placebo in this patient population.
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ABSTRACT: To evaluate the effects of intra-articular botulinum neurotoxin type A (BoNT/A) in dogs with chronic osteo- arthritis. Client-owned dogs with lameness and discomfort attributed to unilateral elbow or hip osteoarthritis were eligible for inclusion (n = 5). All dogs had BoNT/A (25 units) administered to the affected joint (2 elbows, 3 hips). Dogs were evaluated by pressure platform gait analysis before and at two, four, eight, and 12 weeks post-injection, and by client perception of outcome. In experimental limbs, ground reaction forces (peak vertical force and vertical impulse) consistently improved for a variable period of time following intra-articular BoNT/A therapy. These changes were not, however, observed in the contralateral limbs, in which values remained relatively unchanged or decreased. Four out of five owners reported at least some improvement in their dog's condition following treatment. A multimodal approach with the intra-articular administration of BoNT/A may be an option for osteoarthritis patients that are unresponsive to medical management and unable to undergo surgery. However, the findings of this study are preliminary and must be verified by further investigation.Veterinary and Comparative Orthopaedics and Traumatology 01/2010; 23(4):254-8. DOI:10.3415/VCOT-09-07-0076 · 1.03 Impact Factor
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ABSTRACT: To evaluate the analgesic effectiveness of intra-articular botulinum toxin Type B (BoNT/B) in a murine model of chronic degenerative arthritis pain. Chronic arthritis was produced in adult C57Bl6 mice by intra-articular injection of Type IV collagenase into the left knee. Following induction of arthritis, the treatment group received intra-articular BoNT/B. Arthritic control groups were treated with intra-articular normal saline or sham injections. Pain behavior testing was performed prior to arthritis, after induction of arthritis, and following treatments. Pain behavior measures included analysis of gait impairment (spontaneous pain behavior) and joint tenderness evaluation (evoked pain response). Strength was measured as ability to grasp and cling. Visual gait analysis showed significant impairment of gait in arthritic mice that improved 43% after intra-articular BoNT/B, demonstrating a substantial articular analgesic effect. Joint tenderness, measured with evoked pain response scores, increased with arthritis induction and decreased 49.5% after intra-articular BoNT/B treatment. No improvement in visual gait scores or decrease in evoked pain response scores were found in the control groups receiving intra-articular normal saline or sham injections. Intra-articular BoNT/B was safe, and no systemic effects or limb weakness was noted. This study is the first report of intra-articular BoNT/B for analgesia in a murine model of arthritis pain. The results of this study validate prior work using intra-articular neurotoxins in murine models. Our findings show chronic degenerative arthritis pain can be quantitated in a murine model by measuring gait impairment using visual gait analysis scores (spontaneous pain behavior) and joint tenderness scores (evoked pain responses). Reduction of joint pain seen in this study is consistent with our hypothesis of inhibition of release of pain mediators by intra-articular BoNT/B, supporting further investigation of this novel approach to treatment of arthritis pain with intra-articular neurotoxins.Journal of Pain Research 09/2010; 3:161-8. DOI:10.2147/JPR.S12520