Intra-articular Botulinum Toxin Type A: a new approach to treat arthritis joint pain

Recent advances in the management of knee osteoarthritis: a narrative review

Knee osteoarthritis (OA) is a common condition that causes pain and reduces the quality of life for many people. It also leads to high health and financial costs. Managing knee OA pain requires using different methods together for the best results. This review overviews current therapeutic options for knee OA pain, focusing on their efficacy, safety, and potential roles in clinical practice. Topical treatments, such as NSAIDs and capsaicin, offer significant pain relief with minimal systemic side effects and are suitable for initial therapy, together with nonpharmacologic interventions like exercise and, when relevant, weight loss. Oral analgesics, including acetaminophen and opioids, have limited efficacy and serious side effects, making them appropriate only for short-term or rescue therapy. Intra-articular injections, such as corticosteroids, hyaluronic acid, and platelet rich plasma, demonstrate varying levels of efficacy and safety. Nutritional supplements, including curcumin, Boswellia serrata, and glucosaminechondroitin combinations, offer modest benefits and are best used as adjuncts to standart treatment. Nonpharmacological treatments, such as transcutaneous electrical nerve stimulation (TENS), acupuncture, and local heat therapy, provide variable pain relief and should be customized based on individual patient responses. Targeted biologic agents, such as antibodies to TNF-α, IL-1, and NGF, hold promise for more precise pain relief; however, further research is required to establish their routine use. Treating knee OA pain should be personalized, combining several methods. Research must continue to improve treatments and make them safer.

Efficacy and safety of intra-articular botulinum toxin injection therapy for joint pain: A systematic review and meta-analysis

BACKGROUND

Studies conducted in various animal models of joint pain showed an anti-nociceptive effect of intra-articular botulinum toxin type A (BoNT-A). Randomized controlled trials (RCTs) in humans suggest a potential effect but results are disparate.

OBJECTIVES

To assess the efficacy and safety of intra-articular BoNT-A for the treatment of joint pain.

METHODS

We conducted a systematic review of RCTs comparing the effects of intra-articular BoNT-A to other interventions on pain and activity limitations in the short (<3 months), intermediate (3-6 months) and long term (> 6 months), and their adverse effects, in people with joint pain. We performed a meta-analysis when appropriate. MEDLINE, EMBASE, ClinicalTrials.gov, CINHAL and ICTRP databases were searched from inception to July 9, 2023. Two independent reviewers selected eligible studies and extracted data in a standardized manner. The results of quantitative synthesis were expressed as the standardized mean difference (SMD) (95 % confidence interval).

RESULTS

We included 14 RCTs: 437 participants received an intra-articular injection of BoNT-A and 551 received another intervention. Overall, 7 RCTs (549 participants) compared intra-articular BoNT-A with an intra-articular treatment in the knee: short-, intermediate-, and long-term SMD were -0.35 (-0.82 to 0.12), -0.27 (-0.61 to 0.08), and -0.43 (-1.12 to 0.26) for pain and -0.44 (-0.96 to 0.07), -0.24 (-0.63 to 0.15) and -0.42 (-1.26 to 0.42) for activity limitations, respectively. Two RCTs (68 participants) in the shoulder and 1 RCT (60 participants) in the base-of-thumb showed reduced pain in the short term. Minor adverse events were not rare, but no serious adverse events related to intra-articular BoNT-A were reported.

CONCLUSIONS

Intra-articular BoNT-A may reduce joint pain in the short term for small and medium-sized joints (ie, base-of-thumb and shoulder), but not for large joints (ie, knee).

REGISTRATION

PROSPERO: CRD42021290157 (Date of first submission: 8 November 2021; Date of registration: 8 December 2021).

Myeloid Vamp3 deletion attenuates CFA-induced inflammation and pain in mice via ameliorating macrophage infiltration and inflammatory cytokine production

Persistent inflammation and associated pain significantly impact individuals' quality of life, posing substantial healthcare challenges. Proinflammatory cytokines, released by activated macrophages, play crucial roles in the development of chronic inflammatory conditions such as rheumatoid arthritis. To identify and evaluate potential therapeutic interventions targeting this process for mitigating inflammation and pain, we created myeloid cell-specific knockout of Vamp3 (vesicle-associated membrane protein 3) mice (Vamp3 Δmyel) by crossing LysM-Cre mice with newly engineered Vamp3flox/flox mice. Bone marrow-derived macrophages and peritoneal resident macrophages from Vamp3 Δmyel mice exhibited a significant reduction in TNF-α and IL-6 release compared to control mice. Moreover, Vamp3 deficiency led to decreased paw edema and ankle joint swelling induced by intraplantar injection of complete Freund's adjuvant (CFA). Furthermore, Vamp3 depletion also mitigated CFA-induced mechanical allodynia and thermal hyperalgesia. Mechanistically, Vamp3 loss ameliorated the infiltration of macrophages in peripheral sites of the hind paw and resulted in reduced levels of TNF-α and IL-6 in the CFA-injected paw and serum. RT-qPCR analysis demonstrated downregulation of various inflammation-associated genes, including TNF-α, IL-6, IL-1β, CXCL11, TIMP-1, COX-2, CD68, and CD54 in the injected paw at the test day 14 following CFA administration. These findings highlight the novel role of Vamp3 in regulating inflammatory responses and suggest it as a potential therapeutic target for the development of novel Vamp-inactivating therapeutics, with potential applications in the management of inflammatory diseases.

Intra-Articular Injection of Botulinum Toxin for the Treatment of Knee Osteoarthritis: A Systematic Review of Randomized Controlled Trials

The purpose of the present paper was to review the available evidence on intra-articular botulinum toxin (BTX) injection in the treatment of knee osteoarthritis and to compare it to other conservative treatment options. A systematic review of the literature was performed on the PubMed, Scopus, Cochrane Library, Web of Science, Pedro and Research Gate databases with the following inclusion criteria: (1) randomized controlled trials (RCTs), (2) written in the English language, and (3) published on indexed journals in the last 20 years (2001-2021) dealing with the use of BTX intra-articular injection for the treatment of knee OA. The risk of bias was assessed using the Cochrane Risk of Bias tool for RCTs. Nine studies involving 811 patients in total were included. Patients in the control groups received different treatments: conventional physiotherapy, hyaluronic acid injection or prolotherapy or a combination thereof in 5 studies, steroid infiltrative therapy (triamcinolone) in 1 study, placebo in 2, and local anesthetic treatment in 1 study. Looking at the quality of the available literature, two of the included studies reached "Good quality" standard, three were ranked as "Fair", and the rest were considered "Poor". No major complications or serious adverse events were reported following intra-articular BTX, which provided encouraging pain relief, improved motor function, and quality of life. Based on the available data, no clear indication emerged from the comparison of BTX with other established treatments for knee OA. The analysis of the available RCTs on BTX intra-articular injection for the treatment of knee OA revealed modest methodological quality. However, based on the data retrieved, botulinum toxin has been proven to provide good short-term outcomes, especially in patients with pain sensitization, by modulating neurotransmitter release, peripheral nociceptive transduction, and acting on the control of chronic pain from central sensitization.

The effect of intraarticular botulinum toxin-A injection on symptoms of temporomandibular joint disorder

INTRODUCTION

Application of arthrocentesis in temporomandibular joint disorders preferred and suggested therapeutic treatment option in recent years. This study was designed to investigate and compare the effect of intra-articular injection of botulinum toxin-A (Btx-A) on pain and mouth opening after arthrocentesis in nonreduction disc displacement.

MATERIALS AND METHODS

This restrospective study was conducted on 30 patients with a visual analogue scale is higher than five and limited mouth opening. Patients were divided into 2 groups as conventional arthrocentesis group (group A) and intra-articular Btx-A injection following arthrocentesis group (group B). Maximum mouth openining and temporomandibular joint pain were measured in preoperative (t0) and at postoperative 1^st-week (t1), 1^st-month (t2) and 6^th-month (t3).

RESULTS

When VAS scores of group A and group B were examined, no statistical difference was observed at t0 and t1 time intervals; an increased in mouth opening values and decreased VAS score values were observed in both groups in the 1^st month (t2) and 6^{th (}t3) months, mostly in group A.

CONCLUSION

İntra-articular injection of Btx-A following arthrocentesis can induce mouth opening and reduce the pain and dysfunction in patients with anterior disc displacement.

Safety and synovial inflammatory response after intra-articular injection of botulinum toxin type A in healthy horses

Botulinum toxin type A (BoNT-A) is a promising alternative for patients suffering from chronic joint pain. The aim of this study was to investigate whether a single injection of BoNT-A would produce adverse effects on clinical parameters and synovial parameters as well as lameness. One randomly selected radiocarpal joint was treated with 50 U of BoNT-A in eight horses, and the contralateral joint received saline solution. All horses received injections at day 0 and were re-evaluated twice daily for seven days for heart rate (HR), respiratory rate (RR), rectal temperature (RT), mucous membrane color, capillary refill time, intestinal motility, appetite, water intake, defecation, urination, and attitude. At these same time points, joint pain and circumference were assessed. Objective lameness evaluations were performed once daily for seven days and synovial fluid samples were collected at baseline, post-injection hour (PIH) 24 and PIH 168 and evaluated for synovial fluid parameters. HR and RT remained clinically unaltered, despite oscillations over time (p=0.001). The remaining clinical parameters were unaltered by treatment or time (p>0.05). Joint pain was not elicited by flexion and palpation in both limbs as well as carpal circumference was not altered (p=0.88). Lameness was observed only on saline limbs. Cellular parameters evaluated in synovial fluid samples from both carpi had significantly increased from baseline to PIH 24, decreasing at PIH 168 (p<0.05). It was concluded that the injection of 50 U BoNT-A is suggested to be a safe therapy for intra-articular use in horses and must be verified by further investigation.

The efficacy and safety of Botulinum Toxin Type A in painful knee osteoarthritis: a systematic review and meta-analysis

Objective

A systematic review and meta-analysis was carried out to evaluate the efficacy and safety of Botulinum Toxin Type A in painful knee osteoarthritis.

Methods

The EMBASE and MEDLINE databases were searched to identify randomized controlled trials (RCTs) of Botulinum Toxin Type A in the treatment of painful knee osteoarthritis. The references of included literature were also searched.

Results

Five articles involving 5 RCTs including 314 patients were included in this analysis. There was a significant difference between Botulinum Toxin Type A and placebo in the visual analog scale (VAS) pain scale and Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) questionnaire score in both the short-term (≤4 weeks) and long-term (≥8 weeks) treatment period. There were no serious adverse events in the Botulinum Toxin Type A groups.

Conclusions

This meta-analysis suggests that Botulinum Toxin Type A is effective and safe in the painful knee OA treatment. However, high-quality randomized controlled studies are still needed to further confirm our findings.

Efficacy of Intra-Articular Botulinum Toxin in Osteoarticular Joint Pain: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

This study was conducted with the aim of evaluating the efficacy of intra-articular injections of botulinum toxin type A (BT-A) into the painful joint diseases through a systematic review of the literature and a meta-analysis of controlled randomized trials. Intra-articular therapies (corticosteroids, hyaluronic acid) have limited efficacy and run a risk of toxicity in patients with joint pain. New therapeutic options are needed to treat painful osteoarticular disease.

METHODS

We searched via Pubmed, American College of Rheumatology, and European League Against Rheumatism congresses, and gray literature for the studies reported until June 2016 and addressing the issue of BT intra-articular injections in patients with refractory joint pain. Randomized trials were included. For the meta-analysis, we compared a numeric rating scale (NRS) from 0 to 10 before treatment and at 1 or 2 months and 6 months after in the BT-A and the control groups for each study. We also compared separately low dose and high dose of BT at 1 or 2 months' evaluation.

RESULTS

In a total of 269 selected articles, 8 were analyzed and 6 studies were included in the meta-analysis involving a total of 382 patients. On comparing the NRS rating for 5 trials, at 1 or 2 months irrespective of the dose of BT, 4 trials showed a positive effect of BT compared with the control on the NRS and 1 found no effect; the overall weighted mean difference [95% confidence interval (CI)] was -1.10 (-1.62, -0.58) (P<0.0001, I=63%). Among the 4 trials with a low dose of BT (100 U), comparing NRS at 1 or 2 months, 3 trials showed significant results with a positive effect of BT-A injection compared with the control on the NRS; the fourth study failed to find any effect. The overall weighted mean difference (95% CI) was -0.95 (-0.02, -1.88) (P=0.05, I=67%). In the 2 trials using a high dose of BT (200 U) comparing NRS at 1 or 2 months, there was an almost zero effect of BT, with an overall weighted mean difference (95% CI) of 0.13 (-0.55, 0.81) (P=0.71, I=0%). In the 3 trials comparing NRS at 6 months there was an overall weighted mean difference (95% CI) of -0.57 (-1.98, 0.83) (P=0.42, I=73%).

CONCLUSIONS

BT-A intra-articular injections have short-term benefits with a statistically significant decrease in the NRS pain score of around 1 point in patients with refractory joint pain. A decrease in the pain score was also observed at 6 months but with a nonsignificant result.

Comparison between intra-articular Botulinum toxin type A, corticosteroid, and saline in knee osteoarthritis: a randomized controlled trial

OBJECTIVE

To compare the effectiveness of intra-articular injection (IAI) with Botulinum toxin type A (BTA), triamcinolone hexacetonide (TH), and saline in primary knee osteoarthritis.

DESIGN

A randomized controlled trial, with blinded patients and assessor.

SETTING

Outpatient rheumatology service.

SUBJECTS

Patients with knee osteoarthritis grades II and III.

INTERVENTIONS

Patients received IAI with 100 IU BTA, 40 mg TH, or isotonic saline solution (SS) 0.9%.

MAIN MEASURES

Patients were assessed at baseline and at 4, 8, and 12 weeks with the following instruments: visual analog scale for pain during movement (VASm; primary outcome) and visual analog scale for pain at rest (VASr), Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, 6-minute walk test, Timed Up and Go test, Short Form (SF)-36 questionnaire, range of motion of knee, and ultrasound (US) measurement of synovial hypertrophy.

RESULTS

In total, 105 patients were randomized, with 35 in each group; 96 were female (91.4%) and 9 were male (8.6%), with a mean age of 64.2 years (±6.9). At 12 weeks, the TH group showed better results only for VASm. At four weeks, the TH group showed better results than the BTA and SS groups for VASm (-68.9% (37.8) vs. -35.3% (40.3) vs. -35.9% (51.4)), WOMAC pain (-56.0% (30.7) vs. -30.8% (34.3) vs. -30.0% (39.9)), WOMAC stiffness (-53.4% (38.4) vs. -17.2% (59.3) vs. -17.3% (78.1)), WOMAC function (-48.2% (34.6) vs. 30.8% (33.6) vs. -13.6% (64.9)), WOMAC total score (-51.2% (31.0) vs. -30.9% (30.0) vs. -18.8% (54.8)), and US measurement of synovial hypertrophy (-11.6% (44.9) vs. -1.5% (47.9) vs. +28.6% (81.3)).

CONCLUSION

IAI with TH had a higher effectiveness than that with TBA or SS in the short-term assessment (four weeks) for pain in movement, WOMAC, and US measurement of synovial hypertrophy.

Pilot randomized controlled trials in the orthopaedic surgery literature: a systematic review

BACKGROUND

The primary objective of this systematic review is to examine the characteristics of pilot randomized controlled trials (RCTs) in the orthopaedic surgery literature, including the proportion framed as feasibility trials and those that lead to definitive RCTs. This review aim to answer the question of whether pilot RCTs lead to definitive RCTs, whilst investigating the quality, feasibility and overall publication trends of orthopaedic pilot trials.

METHODS

Pilot RCTs in the orthopaedic literature were identified from three electronic databases (EMBASE, MEDLINE, and Pubmed) searched from database inception to January 2018. Search criteria included the evaluation of at least one orthopaedic surgical intervention, research on humans, and publication in English. Two reviewers independently screened the pool of pilot trials, and conducted a search for corresponding definitive trials. Screened pilot RCTs were assessed for feasibility outcomes related to efficiency, cost, and/or timeliness of a large-scale clinical trial involving a surgical intervention. The quality of the pilot and definitive trials were assessed using the Checklist to Evaluate a Report of a Non-Pharmacological Trial (CLEAR NPT).

RESULTS

The initial search for pilot RCTs yielded 3857 titles, of which 49 articles were relevant for this review. 73.5% (36/49) of the orthopaedic pilot RCTs were framed as feasibility trials. Of these, 5 corresponding definitive trials (10.2%) were found, of which four were published and one ongoing. Based on author responses, the lack of a definitive RCT following the pilot trial was attributed to a lack of funding, inadequacies in recruitment, and belief that the pilot RCT sufficiently answered the research question.

CONCLUSIONS

Based on this systematic review, most pilot RCTs were characterized as feasibility trials. However, the majority of published pilot RCTs did not lead to definitive trials. This discrepancy was mainly attributed to poor feasibility (e.g. poor recruitment) and lack of funding for an orthopaedic surgical definitive trial. In recent years this discrepancy may be due to researchers saving on time and cost by rolling their pilot patients into the definitive RCT rather than publish a separate pilot trial.

Intra-articular botulinum toxin A for base-of-thumb osteoarthritis: protocol for a randomised trial (RHIBOT)

INTRODUCTION

Recent studies have suggested that intra-articular injection of botulinum toxin A (BTA) may have analgesic effects in degenerative joint diseases. We aim to assess the efficacy of intra-articular injection of BTA associated with splinting in patients with trapeziometacarpal osteoarthritis (TMC OA).

METHODS AND ANALYSIS

We will conduct a randomised double-blind controlled trial. Overall, 60 individuals with TMC OA fulfilling adapted 1990 American College of Rheumatology criteria for hand OA will be recruited in one tertiary care centre in France and randomised to receive splinting + a single ultrasound-guided injection in the TMC joint of 50 Allergan Units of BTA resuspended in 1 mL saline or splinting +1 mL saline. Randomisation will be centralised. The allocation ratio will be 1:1. The primary outcome will be the mean change from baseline in base-of-thumb pain on a self-administered 11-point Numeric Rating Scale in 10-point increments at 3 months after injection. Secondary outcomes will be the mean change in base-of-thumb pain at 1 and 6 months, mean change in hand-specific activity limitations assessed by the self-administered Cochin Hand Function Scale, proportion of responders assessed by the Osteoarthritis Research Society International -Outcome Measures in Rheumatology (OMERACT) criteria and consumption of analgesics and non-steroidal anti-inflammatory drugs assessed by a self-administered 4-class scale at 3 and 6 months. Cointerventions will be allowed in both groups and will be self-reported. Adverse events will be recorded at 3 and 6 months. Participants, care providers and statisticians will be blinded to the allocated treatment.

ETHICS AND DISSEMINATION

The RHIBOT trial has been authorised by the Agence Nationale de Sécurité du Médicament and approved by the Comité de Protection des Personnes de Tours Ouest-1. The findings of the study will be disseminated in peer-reviewed journals and at conferences. If the results are positive, intra-articular BTA could be an efficient and safe complementary therapeutic option for patients with TMC OA.

DATE AND VERSION IDENTIFIER OF THE PROTOCOL

8 January 2018, V. 2.0.

TRIAL REGISTRATION NUMBER

NCT03187626; Pre-results.

Assessing adverse effects of intra-articular botulinum toxin A in healthy Beagle dogs: A placebo-controlled, blinded, randomized trial

OBJECTIVE

To investigate the clinical, cytological, and histopathological adverse effects of intra-articularly injected botulinum toxin A in dogs and to study whether the toxin spreads from the joint after the injection.

METHODS

A longitudinal, placebo-controlled, randomized clinical trial was conducted with six healthy laboratory Beagle dogs. Stifle joints were randomized to receive either 30 IU of onabotulinum toxin A or placebo in a 1:1 ratio. Adverse effects and spread of the toxin were examined by evaluating dynamic and static weight-bearing of the injected limbs, by assessing painless range of motion and pain on palpation of joints, and by performing synovial fluid analysis, neurological examination, and electrophysiological recordings at different examination time-points in a 12-week period after the injections. The dogs were then euthanized and autopsy and histopathological examination of joint structures and adjacent muscles and nerves were performed.

RESULTS

Intra-articular botulinum toxin A did not cause local weakness or injection site pain. Instead, static weight-bearing and painless range of motion of stifle joints decreased in the placebo limbs. No clinically significant abnormalities associated with intra-articular botulinum toxin A were detected in the neurological examinations. Electrophysiological recordings showed low compound muscle action potentials in two dogs in the botulinum toxin A-injected limb. No significant changes were detected in the synovial fluid. Autopsy and histopathological examination of the joint and adjacent muscles and nerves did not reveal histopathological adverse effects of the toxin.

CONCLUSION

Intra-articular botulinum toxin A does not produce significant clinical, cytological, or histopathological adverse effects in healthy dogs. Based on the electrophysiological recordings, the toxin may spread from the joint, but its clinical impact seems to be low.

The effect of intra-articular botulinum toxin A on substance P, prostaglandin E2, and tumor necrosis factor alpha in the canine osteoarthritic joint

Background

Recently, intra-articular botulinum toxin A (IA BoNT A) has been shown to reduce joint pain in osteoarthritic dogs. Similar results have been reported in human patients with arthritis. However, the mechanism of the antinociceptive action of IA BoNT A is currently not known. The aim of this study was to explore this mechanism of action by investigating the effect of IA BoNT A on synovial fluid (SF) and serum substance P (SP), prostaglandin E₂ (PGE₂), and tumor necrosis factor alpha (TNF-α) in osteoarthritic dogs. Additionally, the aim was to compare SF SP and PGE₂ between osteoarthritic and non-osteoarthritic joints, and investigate associations between SP, PGE₂, osteoarthritic pain, and the signalment of dogs. Thirty-five dogs with chronic naturally occurring osteoarthritis and 13 non-osteoarthritic control dogs were included in the study. Osteoarthritic dogs received either IA BoNT A (n = 19) or IA placebo (n = 16). Serum and SF samples were collected and osteoarthritic pain was evaluated before (baseline) and 2 and 8 weeks after treatment. Osteoarthritic pain was assessed with force platform, Helsinki Chronic Pain Index, and joint palpation. Synovial fluid samples were obtained from control dogs after euthanasia. The change from baseline in SP and PGE₂ concentration was compared between the IA BoNT A and placebo groups. The synovial fluid SP and PGE₂ concentration was compared between osteoarthritic and control joints. Associations between SP, PGE₂, osteoarthritic pain, and the signalment of dogs were evaluated.

Results

There was no significant change from baseline in SP or PGE₂ after IA BoNT A. Synovial fluid PGE₂ was significantly higher in osteoarthritic compared to control joints. Synovial fluid PGE₂ correlated with osteoarthritic pain. No associations were found between SP or PGE₂ and the signalment of dogs. The concentration of TNF-α remained under the detection limit of the assay in all samples.

Conclusions

The results suggest that the antinociceptive effect of IA BoNT A in the joint might not be related to the inhibition of SP nor PGE₂. Synovial fluid PGE₂, but not SP, could be a marker for chronic osteoarthritis and pain in dogs.

Intra-articular onabotulinumtoxinA in osteoarthritis knee pain: effect on human mechanistic pain biomarkers and clinical pain

OBJECTIVES

OnabotulinumtoxinA (onabotA) attenuates peripheral nociceptive transduction and consequently neuronal firing. The aim of this mechanistic study was to evaluate the effect of intra-articular (IA) onabotA in patients with painful knee osteoarthritis (OA).

METHOD

We conducted a double-blind, randomized, placebo-controlled, 12-week trial using a single ultrasound-guided IA injection of onabotA (200 U). Patients (N = 121) were randomized to receive onabotA (n = 61) or placebo (n = 60). Mechanistic pain biomarkers and clinical outcomes were used for profiling the effect. The biomarkers were pressure pain thresholds (PPTs) from the knee joint (localized sensitization) and extra-articular sites (widespread sensitization), and wind-up pain (central sensitization). Clinical assessments included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), average daily pain (ADP), patient global impression of change (GIC), and rescue medication. The painDETECT questionnaire (PD-Q) was used for subgrouping patients (nociceptive, neuropathic, and mixed/uncertain).

RESULTS

The nociceptive and non-nociceptive groups were identical with respect to all baseline data. No significant differences in clinical efficacy parameters were found between onabotA and placebo in the entire population. The nociceptive group showed significant improvement after IA onabotA at week 8 for all WOMAC outcomes, ADP at weeks 9 and 10, and patient GIC at week 12, and significant reduction in rescue medication counts within each 14-day period at weeks 9 and 10. After 4, 8, and 12 weeks, significant correlations were obtained in the onabotA group between ADP (both the entire group and the nociceptive group) and various sensitization parameters. The nociceptive group showed pronounced effects on widespread sensitization.

CONCLUSIONS

Intra-articular onabotA given to patients with nociceptive knee OA reduced pain sensitization together with improvement in pain and function.

The effect of intra-articular vanilloid receptor agonists on pain behavior measures in a murine model of acute monoarthritis

Arthritis is the most common cause of disability in the US, and the primary manifestation of arthritis is joint pain that leads to progressive physical limitation, disability, morbidity, and increased health care utilization. Capsaicin (CAP) is a vanilloid agonist that causes substance P depletion by interacting with vanilloid receptor transient receptor potential V1 on small unmyelinated C fibers. It has been used topically for analgesia in osteoarthritis with variable success. Resiniferatoxin (RTX) is an ultra potent CAP analog. The aim of this study was to measure the analgesic effects of intra-articular (IA) administration of CAP and RTX in experimental acute inflammatory arthritis in mice. Evoked pain score (EPS) and a dynamic weight bearing (DWB) device were used to measure nociceptive behaviors in a murine model of acute inflammatory monoarthritis. A total of 56 C57B16 male mice underwent EPS and DWB testing – 24 nonarthritic controls and 32 mice with carrageenan-induced arthritis. The effects of pretreatment with 0.1% CAP, 0.0003% RTX, or 0.001% RTX were measured. Nociception was reproducibly demonstrated by increased EPS and reduced DWB measures in the affected limb of arthritic mice. Pretreatment with 0.001% RTX resulted in statistically significant improvement in EPS and DWB measures when compared with those observed in carrageenan-induced arthritis animals. Pretreatment with IA 0.0003% RTX and IA 0.01% CAP resulted in improvement in some but not all of these measures. The remaining 24 mice underwent evaluation following treatment with 0.1% CAP, 0.0003% RTX, or 0.001% RTX, and the results obtained were similar to that of naïve, nonarthritic mice.

Effects of intrabursal administration of botulinum toxin type B on lameness in horses with degenerative injury to the podotrochlear apparatus

OBJECTIVE

To determine the safety and short-term efficacy of intrabursal administration of botulinum toxin type B (BTXB) to alleviate lameness in horses with degenerative injury to the podotrochlear apparatus (PA).

ANIMALS

10 Quarter Horses with degenerative injury to the PA.

PROCEDURES

Degenerative injury to the PA was confirmed with diagnostic analgesia and imaging. Then, BTXB (3.8 to 4.5 U/kg) was injected into the podotrochlear (navicular) bursa of each horse. Three horses were used in a safety evaluation. Subsequently, video recordings of lameness evaluations were obtained for 7 client-owned horses 5 days before (baseline) and 7 and 14 days after BTXB treatment and used to determine the effect of BTXB injection on lameness; 1 horse was removed from the study 8 days after BTXB treatment. Three investigators who were unaware of the treated forelimbs or time points separately reviewed the recordings and graded the lameness of both forelimbs of the horses.

RESULTS

Improvement in lameness of the treated forelimbs was detected at 1 or both time points after BTXB administration in all horses. However, all horses had some degree of lameness at the end of the study. Two horses developed transient increases in lameness 48 to 72 hours after treatment; lameness resolved uneventfully.

CONCLUSIONS AND CLINICAL RELEVANCE

Intrabursal injection of BTXB temporarily alleviated chronic lameness in horses with degenerative injury to the PA, without causing serious short-term adverse effects. Further investigation into the potential use of BTXB in horses affected by degenerative injury to the PA is warranted.

Efficacy of intraarticular botulinum toxin A and intraarticular hyaluronate plus rehabilitation exercise in patients with unilateral ankle osteoarthritis: a randomized controlled trial

Background

There was an increasing requirement for novel treatments of osteoarthritis (OA). The aim was to compare the efficacy of intraarticular Botulinum toxin type A (BoNT-A) and intraarticular hyaluronate plus rehabilitation exercise in patients with ankle OA.

Methods

This was a prospective, randomized, assessor-blinded study with a 6-month follow-up period, conducted in the outpatient rehabilitation department at a university-affiliated tertiary care medical center. Seventy-five patients with symptomatic ankle OA (Kellgren-Lawrence grade 2) were randomized to receive either a single 100-unit BoNT-A injection into the target ankle (n = 38) or a single hyaluronate injection plus 12 sessions of rehabilitation exercise (30 minutes/day, 3 times/week for 4 weeks) (n = 37). The primary outcome measure was the Ankle Osteoarthritis Scale (AOS). Secondary outcome measures included American Orthopedic Foot and Ankle Society (AOFAS) Ankle/Hindfoot Score, visual analog scale (VAS) for ankle pain, single leg stance test (SLS), Timed “Up-and-Go” test (TUG), consumption of rescue analgesics and global patient satisfaction.

Results

There were no significant between-group differences in total AOS scores, pain subscale and disability subscale scores (adjusted mean difference AMD = -0.2, 95% CI = (-0.5, 0.2), p = 0.39; AMD = -0.1, 95% CI = (-0.5, 0.3), p = 0.57; AMD = -0.2, 95% CI = (-0.6, 0.2), p = 0.36). The 2 groups showed no significant differences in AOFAS, VAS, SLS, TUG scores and consumption of rescue analgesics at each follow-up visit, except that the hyaluronate group improved more in SLS than the BoNT-A group at 1-month follow-up. Patients’ satisfaction rate was high, with no serious adverse events. There was no difference in adverse events between the two groups (p = 1.00).

Conclusions

Treatment with intraarticular BoNT-A or hyaluronate injection plus rehabilitation exercise was associated with improvements in pain, physical function and balance in patients with ankle OA. These effects were rapid at 2 weeks and might last for at least 6 months. There was no difference in effectiveness between the two interventions.

Trial registration

The trial was registered at clinical trials.gov (Registry number NCT01760577).

Intra-articular botulinum toxin A for the treatment of osteoarthritic joint pain in dogs: a randomized, double-blinded, placebo-controlled clinical trial

The aim of this study was to investigate the efficacy of intra-articular (IA) botulinum toxin A (IA BoNT A) for the treatment of osteoarthritic joint pain in dogs. The study was a placebo-controlled, randomized, double-blinded clinical trial with parallel group design and 12-week follow-up. Thirty-six dogs with chronic lameness due to stifle, hip or elbow osteoarthritis were randomized to receive an IA injection of 30IU of BoNT A or placebo. The main outcome variables were vertical impulse (VI) and peak vertical force (PVF) measured with a force platform, and Helsinki chronic pain index (HCPI). Subjective pain score and the need for rescue analgesics were secondary variables. The response to treatment was assessed as the change from baseline to each examination week. The variables were analyzed by ANOVA with repeated measurements and results were considered statistically significant if P ⩽ 0.05. The improvement from baseline to 12 weeks after baseline was statistically significant in VI, PVF and HCPI in the treatment group (P=0.001, P=0.054 and P=0.053, respectively). Additionally, there were statistically significant improvements in VI in the treatment group at 2, 4 and 8 weeks after baseline (P=0.037, P=0.016 and P=0.016, respectively). The difference between groups in improvement in VI was statistically significant at 12weeks after baseline (P=0.005). There was no significant change in the subjective pain score or in the requirement for rescue analgesics in either group. No major adverse events thought to be related to trial protocol were detected. These results suggest that IA BoNT A has some efficacy in reducing osteoarthritic pain in dogs.

Efficacy of Long-term Effect and Repeat Intraarticular Botulinum toxin in Patients with Painful Total Joint Arthroplasty: A Retrospective Study

Objective

Based on recent success of intra-articular (IA) Botulinum neurotoxin type A (BoNT/A; OnabotulinumtoxinA) in patients with osteoarthritis, we examined if repeat IA-BoNT/A is an effective antinociceptive in patients with refractory arthroplasty pain.

Methods

11 patients with refractory chronic arthroplasty joint pain without any evidence of infection or prosthesis loosening were referred by orthopedic surgeons. After discussion of off-label use, each patient underwent IA injection of BoNT/A, repeated based on return of pain on numeric rating scale (NRS) and functional limitation on composite validated scales, Western Ontario McMaster Osteoarthritis index (WOMAC) or Shoulder Pain and Disability (SPADI).

Results

11 patients (10 men, 1 woman) with 14 painful arthroplasty joints (3 bilateral; 12 knee and 2 shoulder) underwent ≥1 IA-BoNT/A injections (8 joints injected once, one joint injected twice only, five joints injected thrice) with doses ranging 100–300 units. Mean age was 68 years (standard deviation, 12) and follow-up ranged 1–28 months. Clinically meaningful reduction of 2-units in pain severity and really meaningful reduction in pain severity (50% reduction) were reported by 6/11 patients (6/13 joints) and 3/11 patients (3/13 joints), respectively, 1 month after the first IA-BoNT/A (100-units each). Significant improvements were noted in composite functional scales (WOMAC/SPADI). Pain relief was sustained at 3–4 month follow-up and was reproducible in those who received repeat injections. No significant adverse events were seen in any patients.

Conclusions

A single intra-articular injection of BoNT/A improved pain and function in patients with chronic, refractory painful knee or shoulder arthroplasty, which sustained with repeat injections. Patients who were refractory to the first injection, did not respond to subsequent injections of higher dose of IA-BoNT/A.

Anti-inflammatory effects of botulinum toxin type a in a complete Freund's adjuvant-induced arthritic knee joint of hind leg on rat model

The objective of the study is to verify histopathologically the anti-inflammatory effect of botulinum toxin type A (BoNT-A) in a Complete Freund's Adjuvant (CFA)-induced arthritic knee joint of hind leg on rat model using immunofluorescent staining of anti-ionized calcium-binding adaptor molecule 1 (Iba-1) and interleukin-1β (IL-1β) antibody. Twenty-eight experimental rats were injected with 0.1 ml of CFA solution in the knee joint of the hind leg bilaterally. Three weeks after CFA injection, the BoNT-A group (N = 14) was injected with 20 IU (0.1 ml) of BoNT-A bilaterally while the saline group (N = 14) was injected with 0.1 ml of saline in the knee joint of the hind leg bilaterally. One and two weeks after BoNT-A or saline injection, joint inflammation was investigated in seven rats from each group using histopathological and immune-fluorescent staining of Iba-1 and IL-1β antibody. The number of Iba-1 and IL-1β immune-reactive (IR) cells was counted in the BoNT-A and saline groups for comparison. There was a significant reduction in joint inflammation and destruction in the BoNT-A group at 1 and 2 weeks after BoNT-A injection compared with the saline group. The binding of Iba-1 and IL-1β antibody was significantly lower in the BoNT-A group than the saline group at 1 and 2 weeks after BoNT-A injection. The number of Iba-1 and IL-1β-IR cells at 1 and 2 weeks after the injection of BoNT-A were significantly different from the corresponding number of Iba-1 and IL-1β-IR cells in the saline group. To conclude, BoNT-A had an anti-inflammatory effect in a CFA-induced arthritic rat model, indicating that BoNT-A could potentially be used to treat inflammatory joint pain.

Use of botulinum toxin in musculoskeletal pain

Chronic musculoskeletal pain is a common cause of chronic pain, which is associated with a total cost of $635 billion per year in the U.S. Emerging evidence suggests an anti-nociceptive action of botulinum toxin, independent of its muscle paralyzing action. This review provides a summary of data from both non-randomized and randomized clinical studies of botulinum toxin in back pain and various osteoarticular conditions, including osteoarthritis, tennis elbow, low back pain and hand pain. Three randomized controlled trials (RCTs) of small sizes provide evidence of short-term efficacy of a single intra-articular injection of 100 units of botulinum toxin A (BoNT/A) for the relief of pain and the improvement of both function and quality of life in patients with chronic joint pain due to arthritis. Three RCTs studied intramuscular BoNT/A for tennis elbow with one showing a significant improvement in pain relief compared with placebo, another one showing no difference from placebo, and the third finding that pain and function improvement with BoNT/A injection were similar to those obtained with surgical release. One RCT of intramuscular BoNT/A for low back pain found improvement in pain and function compared to placebo. Single RCTs using local injections of BoNT in patients with either temporomandibular joint (TMJ) pain or plantar fasciitis found superior efficacy compared to placebo. One RCT of intramuscular BoNT/B in patients with hand pain and carpal tunnel syndrome found improvement in pain in both BoNT/B and placebo groups, but no significant difference between groups. Most evidence is based on small studies, but the use of BoNT is supported by a single, and sometimes up to three, RCTs for several chronic musculoskeletal pain conditions. This indicates that botulinum toxin may be a promising potential new treatment for chronic refractory musculoskeletal pain. Well-designed large clinical trials are needed.

Longer-acting and highly potent chimaeric inhibitors of excessive exocytosis created with domains from botulinum neurotoxin A and B

Various human neurogenic hyper-excitability disorders are successfully treated with type A or B BoNT (botulinum neurotoxin). The BoNT/A complex is widely used because of its longer-lasting benefits; also, autonomic side-effects are more often reported for BoNT/B. To establish if this distinct effect of BoNT/B could be exploited therapeutically, BoNT/A was modified so that it would bind the more abundant BoNT/B acceptor in rodents while retaining its desirable persistent action. The advantageous protease and translocation domain of BoNT/A were recombinantly combined with the acceptor-binding moiety of type B [H(C)/B (C-terminal half of BoNT/B heavy chain)], creating the chimaera AB. This purified protein bound the BoNT/B acceptor, displayed enhanced capability relative to type A for intraneuronally delivering its protease, cleaved SNAP-25 (synaptosome-associated protein of 25 kDa) and induced a more prolonged neuromuscular paralysis than BoNT/A in mice. The BA chimaera, generated by substituting H(C)/A (C-terminal half of BoNT/A heavy chain) into BoNT/B, exhibited an extremely high specific activity, delivered the BoNT/B protease via the BoNT/A acceptor into neurons, or fibroblast-like synoviocytes that lack SNAP-25, cleaving the requisite isoforms of VAMP (vesicle-associated membrane protein). Both chimaeras inhibited neurotransmission in murine bladder smooth muscle. BA has the unique ability to reduce exocytosis from non-neuronal cells expressing the BoNT/A-acceptor and utilising VAMP, but not SNAP-25, in exocytosis.

Evidence-based knee injections for the management of arthritis

OBJECTIVE

Arthritis of the knee affects 46 million Americans. We aimed to determine the level of evidence of intraarticular knee injections in the management of arthritic knee pain.

METHODS

We systematically searched PUBMED/MEDLINE and the Cochrane databases for articles published on knee injections and evaluated their level of evidence and recommendations according to established criteria.

RESULTS

The evidence supports the use of intraarticular corticosteroid injections for rheumatoid arthritis (1A+ Level), osteoarthritis (1A+ Level), and juvenile idiopathic arthritis (2C+ Level). Pain relief and functional improvement are significant for months up to 1 year after the injection. Triamcinolone hexacetonide offers an advantage over triamcinolone acetonide and should be the intraarticular steroid of choice (2B+ Level). Intraarticular injection of hyaluronate may provide longer pain relief than steroid injection in osteoarthritis (2B+ Level). It can also be effective for rheumatoid arthritis knee pain (1A+ Level). However, it is only recommended for patients with significant surgical risk factors and for patients with mild radiographic disease in whom conservative treatment has failed (2B± Level). Botulinum toxin type A injection is effective in reducing arthritic knee pain (2B+ Level), and so is tropisetron (2B+ Level) and tanezumab (2B+ Level). The new agents, such as rAAV2-TNFR:Fc, SB-210396/CE 9.1, and various radioisotopes have provided various degrees of success, but their long-term safety and efficacy remains to be determined.

CONCLUSIONS

We conclude that strong evidence supports the use of intraarticular knee injection as a valuable intervention in the continuum of management of arthritis between conservative treatment and knee surgeries.

Neuromodulators for pain management in rheumatoid arthritis

BACKGROUND

Pain management is a high priority for patients with rheumatoid arthritis (RA). Despite deficiencies in research data, neuromodulators have gained widespread clinical acceptance as adjuvants in the management of patients with chronic musculoskeletal pain.

OBJECTIVES

The aim of this review was to determine the efficacy and safety of neuromodulators in pain management in patients with RA. Neuromodulators included in this review were anticonvulsants (gabapentin, pregabalin, phenytoin, sodium valproate, lamotrigine, carbamazepine, levetiracetam, oxcarbazepine, tiagabine and topiramate), ketamine, bupropion, methylphenidate, nefopam, capsaicin and the cannabinoids.

SEARCH METHODS

We performed a computer-assisted search of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, 4th quarter), MEDLINE (1950 to week 1 November 2010), EMBASE (Week 44, 2010) and PsycINFO (1806 to week 2 November 2010). We also searched the 2008 and 2009 American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) conference abstracts and performed a handsearch of reference lists of articles.

SELECTION CRITERIA

We included randomised controlled trials which compared any neuromodulator to another therapy (active or placebo, including non-pharmacological therapies) in adult patients with RA that had at least one clinically relevant outcome measure.

DATA COLLECTION AND ANALYSIS

Two blinded review authors independently extracted data and assessed the risk of bias in the trials. Meta-analyses were used to examine the efficacy of a neuromodulator on pain, depression and function as well as their safety.

MAIN RESULTS

Four trials with high risk of bias were included in this review. Two trials evaluated oral nefopam (52 participants) and one trial each evaluated topical capsaicin (31 participants) and oromucosal cannabis (58 participants).The pooled analyses identified a significant reduction in pain levels favouring nefopam over placebo (weighted mean difference (WMD) -21.16, 95% CI -35.61 to -6.71; number needed to treat (NNT) 2, 95% CI 1.4 to 9.5) after two weeks. There were insufficient data to assess withdrawals due to adverse events. Nefopam was associated with significantly more adverse events (RR 4.11, 95% CI 1.58 to 10.69; NNTH 9, 95% CI 2 to 367), which were predominantly nausea and sweating.In a mixed population trial, qualitative analysis of patients with RA showed a significantly greater reduction in pain favouring topical capsaicin over placebo at one and two weeks (MD -23.80, 95% CI -44.81 to -2.79; NNT 3, 95% CI 2 to 47; MD -34.40, 95% CI -54.66 to -14.14; NNT 2, 95% CI 1.4 to 6 respectively). No separate safety data were available for patients with RA, however 44% of patients developed burning at the site of application and 2% withdrew because of this.One small, low quality trial assessed oromucosal cannabis against placebo and found a small, significant difference favouring cannabis in the verbal rating score 'pain at present' (MD -0.72, 95% CI -1.31 to -0.13) after five weeks. Patients receiving cannabis were significantly more likely to suffer an adverse event (risk ratio (RR) 1.82, 95% CI 1.10 to 3.00; NNTH 3, 95% CI 3 to 13). These were most commonly dizziness (26%), dry mouth (13%) and light headedness (10%).

AUTHORS' CONCLUSIONS

There is currently weak evidence that oral nefopam, topical capsaicin and oromucosal cannabis are all superior to placebo in reducing pain in patients with RA. However, each agent is associated with a significant side effect profile. The confidence in our estimates is not strong given the difficulties with blinding, the small numbers of participants evaluated and the lack of adverse event data. In some patients, however, even a small degree of pain relief may be considered worthwhile. Until further research is available, given the relatively mild nature of the adverse events, capsaicin could be considered as an add-on therapy for patients with persistent local pain and inadequate response or intolerance to other treatments. Oral nefopam and oromucosal cannabis have more significant side effect profiles however and the potential harms seem to outweigh any modest benefit achieved.

Efficacy of intra-articular injection of botulinum toxin type A in refractory hemiplegic shoulder pain

OBJECTIVE

To evaluate the efficacy of intra-articular injection of botulinum toxin type A (BTX-A) in relieving hemiplegic shoulder pain (HSP).

DESIGN

Pilot study with assessments before and after BTX-A intra-articular injection.

SETTING

Hospital rehabilitation department.

PARTICIPANTS

Patients (N=5) with HSP refractory to standard treatments and pain score at rest greater than 7 on a pain visual analog scale (VAS) of 0 to 10cm.

INTERVENTION

Intra-articular BTX-A injection.

MAIN OUTCOME MEASURE

Variation in VAS score at rest and during 90° passive arm abduction 2 and 8 weeks after BTX-A intra-articular injection.

RESULTS

Baseline VAS score was 8.7±1 at rest and 9.8±0.4 during passive arm abduction. It clearly decreased at 2 (1.5±1.1 at rest, P=.001; 3±1.2 during arm abduction, P<.001) and 8 weeks (1.5±1.2 at rest, P=.001; 2.3±1.1 during arm abduction, P<.001) after BTX-A intra-articular injection.

CONCLUSIONS

We found a strong correlation between intra-articular BTX-A injection and pain relief in patients with HSP. This result could provide the rationale for blind randomized controlled trials designed to better evaluate the safety and efficacy of intra-articular BTX-A injection in patients with refractory HSP.

Botox A injection for pain after laparoscopic ventral hernia: a case report

INTRODUCTION

Laparoscopic ventral hernia repair has many advantages over open techniques: adequate visualization of the entire abdominal wall, ease of placement of preperitoneal mesh with adequate overlap, and cosmesis. Intense and activity limiting pain is often one inferior aspect of this repair. We report the case of a patient who was intolerant of narcotic pain medicine with activity limiting pain. A novel technique for postoperative pain control was instituted utilizing Botox A (Allergan Inc., Irvine, CA, USA).

METHODS

Botox A was diluted to 2 units per mL and three injection sites were chosen on each side of the abdominal wall. All three muscle bellies (external oblique, internal oblique, and transversus) were identified by ultrasound and 8 mL was injected in each. This resulted in three muscle layers at six sites for a total of 18 injections. A total of 300 units of Botox A were utilized.

RESULTS

Pain scores improved from 10/10 to 2/10 and were durable at 3-month follow up.

CONCLUSION

Botox A provided significant pain control for this patient after laparoscopic ventral hernia repair. Continued prospective study to define long-term outcomes, cost savings, and appropriate timing of injections is underway.

Treatment of frozen shoulder with intra-articular injection of botulinum toxin in shoulder joints

Frozen shoulder, or adhesive capsulitis, is a disease of chronic inflammation and fibrosis involving the shoulder joints. The disease is challenging in clinical practice due to painful treatment course, with disease evolution usually lasting weeks or even months, causing significant discomfort and functional loss. Botulinum toxin (BTX) has been discovered to possess abilities in pain management at various clinical diseases. The actual mechanism is still under investigation, and involves inhibition of neurotransmitter release. In addition, BTX is also found to retard process of fibrosis, which is also a key issue in pathogenesis of frozen shoulder. Therefore, we hypothesize that intra-articular injection of BTX can be an effective alternative for treatment of frozen shoulder.

The role of botulinum toxin in management of pain: an evidence-based review

PURPOSE OF REVIEW

In the present review we discuss the role of botulinum neurotoxins (BoNTs) in the management of different pain conditions, with evidence-based data on the toxins' efficacy on pain and its mechanisms.

RECENT FINDINGS

Experimental in-vitro studies have reported promising results of a novel recombinant chimera of BoNT A and E that inhibits the calcitonin gene-related peptide exocytosis from brainstem sensory neurons. Animal studies in neuropathic pain rat models have reported an analgesic effect of BoNT A given after the neuropathic procedure and a bilateral antinociceptive effect to the unilateral noxious stimuli. There is a growing body of evidence that BoNTs are effective in myofascial pain syndrome, neuropathic pain, and joint pain. The pre-existing evidence that BoNTs are ineffective in migraine or other headache disorders has not yet been challenged. In other pain syndromes, studies published in the last review year have not contributed significantly in either demonstrating or invalidating the research that has so far proved inconclusive.

SUMMARY

The role of BoNTs in management of pain is not yet well established. Larger studies in neuropathic pain, joint pain, and myofascial pain syndrome are needed to fully ascertain the role for BoNT therapy in those areas.

Botulinum neurotoxin for pain management: insights from animal models

The action of botulinum neurotoxins (BoNTs) at the neuromuscular junction has been extensively investigated and knowledge gained in this field laid the foundation for the use of BoNTs in human pathologies characterized by excessive muscle contractions. Although much more is known about the action of BoNTs on the peripheral system, growing evidence has demonstrated several effects also at the central level. Pain conditions, with special regard to neuropathic and intractable pain, are some of the pathological states that have been recently treated with BoNTs with beneficial effects. The knowledge of the action and potentiality of BoNTs utilization against pain, with emphasis for its possible use in modulation and alleviation of chronic pain, still represents an outstanding challenge for experimental research. This review highlights recent findings on the effects of BoNTs in animal pain models.

Botulinum toxin for shoulder pain

BACKGROUND

Recent evidence suggests an anti-nociceptive effect of botulinum toxin.

OBJECTIVES

To compare the efficacy and safety of botulinum toxin in comparison to placebo or other treatment options for shoulder pain.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), Ovid MEDLINE, CINAHL (via EBSCOhost), Ovid SPORTDiscus, EMBASE and Science Citation Index.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing botulinum toxin with placebo or active treatment in people with shoulder pain were included.

DATA COLLECTION AND ANALYSIS

For continuous measures we calculated mean difference (MD), and for categorical measures risk ratio (RR) (with 95% confidence interval (CI)).

MAIN RESULTS

Six RCTs with 164 patients were included. Five RCTs in participants with post-stroke shoulder pain indicated that compared with placebo, a single intramuscular injection of botulinum toxin A significantly reduced pain at three to six months post-injection (MD -1.2 points, 95% CI -2.4 to -0.07; 0 to 10 point scale) but not at one month (MD -1.1 points, 95% CI -2.9 to 0.7). Shoulder external rotation was increased at one month (MD 9.8 degrees , 95% CI 0.2 to 19.4) but not at three to six months. Shoulder abduction, external rotation or spasticity did not differ between groups, nor did the number of adverse events (RR 1.46, 95% CI 0.6 to 24.3).One RCT in arthritis-related shoulder pain indicated that botulinum toxin reduced pain severity (MD -2.0, 95% CI -3.7 to -0.3; 10 point scale) and shoulder disability with a reduction in Shoulder Pain and Disability Index score (MD -13.4, 95% CI -24.9 to -1.9; 100 point scale) when compared with placebo. Shoulder abduction was improved (MD 13.8 degrees, 95% CI 3.2 to 44.0). Serious adverse events did not differ between groups (RR 0.35, 95% CI: 0.11, 1.12).

AUTHORS' CONCLUSIONS

The results should be interpreted with caution due to few studies with small sample sizes and high risk of bias. Botulinum toxin A injections seem to reduce pain severity and improve shoulder function and range of motion when compared with placebo in patients with shoulder pain due to spastic hemiplegia or arthritis. It is unclear if the benefit of pain relief in post-stroke shoulder pain at three to six months but not at one month is due to limitations of the evidence, which includes small sample sizes with imprecise estimates, or a delayed onset of action. More studies with safety data are needed.

Analgesic effects of intra-articular botulinum toxin Type B in a murine model of chronic degenerative knee arthritis pain

Objective:

To evaluate the analgesic effectiveness of intra-articular botulinum toxin Type B (BoNT/B) in a murine model of chronic degenerative arthritis pain.

Methods and materials:

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.

Results:

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.

Conclusions:

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.