Basic aspects of musculoskeletal pain: from acute to chronic pain

Neck Muscle Coactivation Response to Varied Levels of Mental Workload During Simulated Flight Tasks

OBJECTIVE

To evaluate neck muscle coactivation across different levels of mental workload during simulated flight tasks.

BACKGROUND

Neck pain (NP) is highly prevalent among military aviators. Given the complex nature within the flight environment, mental workload may be a risk factor for NP. This may induce higher levels of neck muscle coactivity, which over time may accelerate fatigue, increase neck discomfort, and affect flight task performance.

METHOD

Three counterbalanced mental workload conditions represented by simulated flight tasks modulated by interstimulus frequency and complexity were investigated using the Modifiable Multitasking Environment (ModME). The primary measure was a neck coactivation index to describe the neuromuscular effort of the neck muscles as a system. Additional measures included perceived workload (NASA TLX), subjective discomfort, and task performance. Participants (n = 60; 30M, 30F) performed three test conditions over 1 hr each while seated in a simulated seating environment.

RESULTS

Neck coactivation indices (CoA) and subjective neck discomfort corresponded with increasing level of mental workload. Average CoAs for low, medium, and high workloads were: .0278(SD = .0232), .0286(SD = .0231), and .0295(SD = .0228), respectively. NASA TLX mental, temporal, effort, and overall scores also increased with the level of mental workload assigned. For ModME task performance, the overall performance score, monitoring accuracy, and resource management accuracy decreased while reaction times increased with the increasing level of mental workload. Communication accuracy was lowest with the low mental workload but had higher reaction times relative to increasing workload.

CONCLUSION

Mental workload affects neck muscle coactivation during combinations of simulated flight tasks within a simulated helicopter seating environment.

APPLICATION

The results of this study provide insights into the physical response to mental workload. With increasing multisensory modalities within the work environment, these insights may assist the consideration of physical effects from cognitive factors.

From maca to marijuana: cultural influences on joint pain symptoms and management in urban perimenopausal and early postmenopausal Latinas

OBJECTIVE

The purpose of this qualitative study was to explore the symptom experience and coping strategies for managing joint pain during the menopause transition in urban Latina women.

METHODS

We conducted focus groups with 13 English-speaking peri and early postmenopausal Latinas living in Upper Manhattan in New York City in 2014. Eligible participants were self-identified Latinas aged 45 to 60 years with new onset or worsening joint pain and spontaneous amenorrhea, recruited through flyers and snowball sampling. Focus group interviews conducted in English were audiotaped, transcribed, and analyzed by a bilingual research team, using NVivo software (QSR International) to organize and code themes.

RESULTS

On average, participants were aged 51.7 ± 4.8 years and overweight (body mass index of 29.3 ± 6.7 kg/m2); 10 (76.9%) were Puerto Rican, and the last menstrual period was 1 month to 5 years ago. The following four themes emerged: 1) menopause and joint pain are an alarming package; 2) pain disrupts life and livelihood; 3) medical management is unsatisfactory and raises worries about addiction; and 4) home remedies for coping with pain-from maca to marijuana. Despite access to a world-class medical facility in their neighborhood, women seeking pain relief preferred to self-manage joint pain with exercise, over-the-counter products, and other culturally valued home remedies. Many suffered through it.

CONCLUSIONS

For midlife Latinas, joint pain symptoms may emerge or worsen unexpectedly as part of the menopause transition and carry distressing consequences for daily activities and quality of life. There is a need to develop more culturally specific approaches for menopause-related pain management in this underserved population.

Acute effect of dry needling on trunk kinematics and balance of patients with non-specific low back pain

BACKGROUND

Limited knowledge exists about the effectiveness of dry needling (DN) concerning the torso kinematics in patients with non-specific low back pain (NS-LBP). Acute effects of DN in NS-LBP patients from a functional perspective were investigated.

METHODS

Sixteen NS-LBP patients and 11 healthy individuals (HG) were examined. NS-LBP patients received a single session of DN at the lumbar region. Baseline and immediate post-treatment measurements during flexion-extension and lateral bending of the trunk were conducted for the NS-LBP patients. HG were measured only at baseline to be used as a reference of NS-LBP patients' initial condition. Algometry was applied in NS-LBP patients. Centre of pressure, range of motion of the trunk and its' derivatives were obtained.

FINDINGS

HG performed significantly faster, smoother and with greater mobility in the performed tasks compared to the pre intervention measurements of the NS-LBP patients. For the NS-LBP patients, significant greater angular velocity in frontal plane and significant lower jerk in the sagittal plane were demonstrated post intervention. DN alleviated pain tolerance significantly at the L5 level. Regarding the effectiveness of the DN upon spine kinematics, their derivatives were more sensitive.

INTERPRETATION

It appeared that the pathological type of torso movement was acutely affected by DN. NS-LBP patients showcased smoother movement immediately after the intervention and better control as imprinted in the higher derivative of motion although range of motion did not improve. This quantitative variable may not be subjected to acute effects of DN but rather need additional time and training to be improved.

Impact of Musculoskeletal Pain on Health-Related Quality of Life Among Adults in Saudi Arabia

Background Musculoskeletal pain (MSP) is widely recognized as a prevalent public health issue that affects individuals of various genders and age groups. The aim of this study is to assess the influence of musculoskeletal pain on the quality of life (QoL) of adult individuals living in Saudi Arabia. Method This is a cross-sectional study using an online-administered questionnaire that was distributed via online platforms in Saudi Arabia for the duration between January and August 2023. Three questionnaire instruments were used in this study. The 36-item Short Form Health Survey questionnaire (SF-36), The 5-level EQ-5D version (EQ-5D-5L), and Roland-Morris Disability Questionnaire. Binary logistic regression analysis was used to identify predictors of better QoL and having mild to moderate disability. Results A total of 8359 participants were involved in this study. The most commonly reported sites of musculoskeletal pain were the lower back, neck, and shoulder, accounting for 36.8% (n= 3072), 30.5% (n= 2549), and 30.1% (n= 2514), respectively. The mean pain score for the study participants was 4.3 (SD: 2.3), which indicates mild degree of pain. The median EQ-5D-5L index value for the study participants was 0.827 (0.756-1.00), which demonstrates a high quality of life. The mean SF-36 score for the study participants was 63.11 (17.4), which demonstrates moderate quality of life. The median Roland-Morris Disability score for the study participants was 1.00 (0.00-7.00), which demonstrates a low level of pain-related disability. Male gender, younger age (30-39 years), having higher education attainment, having higher monthly income (more than SAR 20000), and having lower BMI (less than 25.8 kg/cm2) were predictors of better QoL (p<0.05). Conclusion Musculoskeletal pain is a multifactorial condition influenced by structural, physical, psychological, social, lifestyle, and comorbid health elements. It ranges from acute to chronic pain and, despite rarely being fatal, has a significant impact on QoL. Musculoskeletal discomfort varies in terms of intensity, affected regions, and demographic and lifestyle factors. This study sheds light on the multifaceted nature of MSP, its impact on QoL, and the significance of early intervention and individualized management strategies to improve the QoL of those affected.

Prevalence of musculoskeletal pain among architecture undergraduates students: A cross-sectional study

BACKGROUND

Architecture students maintain uncomfortable body postures for hours while designing and constructing project models, putting them at high risk of developing musculoskeletal pain (MSP).

OBJECTIVE

This research aimed to determine the prevalence of MSP among students at the Architecture and Planning College at King Saud University, Saudi Arabia.

METHODS

This descriptive cross-sectional survey study used a self-administered online questionnaire. A total of 123 students (65 female) aged 19-25 years participated. The survey consisted of eight demographic and health status questions and the Extended Nordic Musculoskeletal Questionnaire (NMQ-E). The data were analyzed using descriptive statistics; Mann-Whitney U and chi-square tests were used to compare genders at α= .05.

RESULTS

Approximately 94.3% of architecture students reported pain in at least one body region in the last 12 months, and 87.0% in the last seven days. The highest reported percentage of MSP was neck pain, followed by lower back pain. No differences in MSP were found between genders, except in elbow and hand pain for the last 12 months and elbow pain for the last seven days.

CONCLUSION

There was a high prevalence of MSP among undergraduate architecture students, highlighting the need to prevent occupational health issues at an early stage.

Hyperexcitability of muscle spindle afferents in jaw-closing muscles in experimental myalgia: Evidence for large primary afferents involvement in chronic pain

The goals of this review are to improve understanding of the aetiology of chronic muscle pain and identify new targets for treatments. Muscle pain is usually associated with trigger points in syndromes such as fibromyalgia and myofascial syndrome, and with small spots associated with spontaneous electrical activity that seems to emanate from fibers inside muscle spindles in EMG studies. These observations, added to the reports that large-diameter primary afferents, such as those innervating muscle spindles, become hyperexcitable and develop spontaneous ectopic firing in conditions leading to neuropathic pain, suggest that changes in excitability of these afferents might make an important contribution to the development of pathological pain. Here, we review evidence that the muscle spindle afferents (MSAs) of the jaw-closing muscles become hyperexcitable in a model of chronic orofacial myalgia. In these afferents, as in other large-diameter primary afferents in dorsal root ganglia, firing emerges from fast membrane potential oscillations that are supported by a persistent sodium current (INaP ) mediated by Na+ channels containing the α-subunit NaV 1.6. The current flowing through NaV 1.6 channels increases when the extracellular Ca2+ concentration decreases, and studies have shown that INaP -driven firing is increased by S100β, an astrocytic protein that chelates Ca2+ when released in the extracellular space. We review evidence of how astrocytes, which are known to be activated in pain conditions, might, through their regulation of extracellular Ca2+ , contribute to the generation of ectopic firing in MSAs. To explain how ectopic firing in MSAs might cause pain, we review evidence supporting the hypothesis that cross-talk between proprioceptive and nociceptive pathways might occur in the periphery, within the spindle capsule.

Paradox pain sensitivity using cuff pressure or algometer testing in patients with hemophilia

INTRODUCTION

Pain is a common comorbidity in patients with hemophilia (PwH) due to hemophilic arthropathy. This study aims to explore pain sensitivity in PwH methodologically investigating in cuff pressure testing compared to algometer testing.

METHODS

37 PwH and 35 healthy control subjects (Con) enrolled in this study. Joint health status was assessed. Subjective pain was evaluated using numeric rating scales. Pain sensitivity was measured with pressure algometry and cuff pressure algometry. Pressure pain thresholds of the algometer (PPTa) were measured at knee, ankle joints, and forehead. Subsequently, thresholds of cuff pressure were measured at the left and right lower legs (PPTcuff). In both, lower values represent higher pain sensitivity.

RESULTS

PwH exerted a worse joint health status than Con. Pain sensitivity was higher in PwH compared to Con as PPTa of the knee and ankle joints were lower in PwH. No difference was observed in PPTa at the forehead. Contrastingly, lower pain sensitivity was detected in PwH by higher PPTcuff values compared to Con in both legs.

CONCLUSION

While PPTa of the knee and ankle joints are lower in PwH, PPTcuff are higher in PwH compared to Con. This reveals a paradox situation, highlighting that PwH experience local, joint- and hemophilic arthropathy-related pain, whereas pain sensitivity of non-affected soft tissue structures is lower. The reasons explaining the PPTcuff results remain elusive but might be explained by coping strategies counteracting chronic joint pain, resulting in lower sensitivity at non-affected structures.

Is There a Difference in EEG Characteristics in Acute, Chronic, and Experimentally Induced Musculoskeletal Pain States? a Systematic Review

Electroencephalographic (EEG) alterations have been demonstrated in acute, chronic, and experimentally induced musculoskeletal (MSK) pain conditions. However, there is no cumulative evidence on the associated EEG characteristics differentiating acute, chronic, and experimentally induced musculoskeletal pain states, especially compared to healthy controls. The present systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (PRISMA) to review and summarize available evidence for cortical brain activity and connectivity alterations in acute, chronic, and experimentally induced MSK pain states. Five electronic databases were systematically searched from their inception to 2022. A total of 3471 articles were screened, and 26 full articles (five studies on chronic pain and 21 studies on experimentally induced pain) were included for the final synthesis. Using the Downs and Black risk of assessment tool, 92% of the studies were assessed as low to moderate quality. The review identified a 'very low' level of evidence for the changes in EEG and subjective outcome measures for both chronic and experimentally induced MSK pain based on the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) criteria. Overall, the findings of this review indicate a trend toward decreased alpha and beta EEG power in evoked chronic clinical pain conditions and increased theta and alpha power in resting-state EEG recorded from chronic MSK pain conditions. EEG characteristics are unclear under experimentally induced pain conditions.

Novel Techniques for Musculoskeletal Pain Management after Orthopedic Surgical Procedures: A Systematic Review

Effective postoperative pain management is critical for recovery after orthopedic surgery, but often remains inadequate despite multimodal analgesia. This systematic review synthesizes evidence on innovative modalities for enhancing pain control following major orthopedic procedures. Fifteen randomized controlled trials and comparative studies evaluating peripheral nerve blocks, local anesthetic infiltration, cryotherapy, transcutaneous electrical stimulation, adjunct medications, and other techniques are included. Thematic analysis reveals that peripheral nerve blocks and local anesthetic infiltration consistently demonstrate reduced pain scores, opioid consumption, and side effects versus conventional analgesia alone. Oral multimodal medications also show promise as part of opioid-sparing regimens. Adjunctive approaches like cryotherapy, music, and dexmedetomidine require further research to optimize protocols. Despite promising innovations, critical knowledge gaps persist regarding comparative effectiveness, optimal interventions and dosing, combination strategies, cost-effectiveness, and implementation. High-quality randomized controlled trials using standardized protocols are essential to guide the translation of enhanced multimodal regimens into clinical practice. This review provides a framework for pursuing research priorities and advancing evidence-based postoperative pain management across orthopedic surgeries.

Musculoskeletal Injury Prevalence, Pain Perception, and Physical Activity Level Among Brazilian Strength and Cross-Training Practitioners

In this study, we sought to determine the prevalence of musculoskeletal injuries, perceived pain, and physical activity level among Brazilian practitioners of strength training (ST) and functional fitness (FF). Participants were 311 men and women who trained in 10 FF training centers and seven ST gyms. Each participant completed surveys of the prevalence of musculoskeletal injuries, their pain perception, and their physical activity level. A chi square test was used to analyze associations between groups and distributions of injuries. When any significant difference was observed, the difference score was analyzed through the adjusted residual values. Fisher's exact test was used to determined the associations between musculoskeletal injury prevalence and training modality (FF and ST) and between musculoskeletal injury prevalence and practice frequency (times/wk). To measure the magnitude of association between variables, the Phi coefficient was calculated for 2x2 associations and Cramer's V was used whenever the distributions were outside this standard. When the dependent variable presented a dichotomous characteristic, an Odds Ratio (OR) was calculated with a confidence interval of 95%. We found a higher musculoskeletal injury prevalence in the axial skeleton (n = 52; 83.88%) in FF practitioners and in the lower limbs of ST practitioners (n = 9; 52.96%). When the physical activity level cutoff point was set at 300 minutes per week, there was a significant relationship between physical activity and training modality (p = 0.005). There was also a significant association between pain perception and musculoskeletal injury (p < 0.001). Clinical follow-up was a protective factor to being injured (OR = 0.18; CI = 0.06-0.49), and, even after multivariate analysis this significant association was maintained (OR = 0.03; CI = 0.01 - 0.08). Thus, FF practitioners reported more musculoskeletal injuries than STs, and follow-up medical or physical therapy was a protective factor to these injuries. FF practitioners also had a higher level of weekly physical activity weekly than ST practitioners. Functional fitness practitioners may be at a higher risk of injuries than those who participate in traditional strength training.

Trigger Point Injections Versus Medical Management for Acute Myofascial Pain: A Systematic Review and Meta-Analysis

Myofascial pain is a common problem resulting in musculoskeletal pain characterized by myofascial trigger points. These trigger points can cause substantial discomfort and functional limitations. This meta-analysis aims to assess the effectiveness and safety of trigger point injections versus medical management alone in treating acute onset myofascial pain. A thorough search was conducted across four databases, namely, PubMed, SCOPUS, Web of Science (WOS), and Cochrane Library, to identify randomized controlled trials that compared the effectiveness of trigger point injections versus medical management for the treatment of acute myofascial pain. The search encompassed articles published from the databases' inception until June 2023. The relevant data were extracted and analyzed using the standardized mean difference (SMD) and 95% confidence interval (CI). Of the 1151 records identified, four met the inclusion criteria for the systematic review, and all were included in the meta-analysis. The analysis of four randomized controlled trials (RCTs) showed that trigger point injections were effective in reducing pain scores compared to medical treatment (SMD = -2.09 (95% CI: -3.34 to -0.85, P = 0.001)). The data revealed a negative standardized mean difference, which was significant and consistent in favor of trigger point injections. Overall, these findings highlight the beneficial impact of trigger point injections in reducing acute myofascial pain when compared to isolated medical management.

Cross-Cultural Adaptation and Validation of a Marathi Version of the Versus Arthritis Musculoskeletal Health Questionnaire (MSK-HQ)

Introduction Musculoskeletal (MSK) well-being plays a crucial role in determining one's quality of life. Musculoskeletal Health Questionnaire (MSK-HQ) score is a tool recently developed by the Versus Arthritis group of Oxford University in English to measure MSK health. Marathi is a regional language in western India spoken by more than 100 million people. There is a scarcity of valid and reliable tools to measure MSK health in this language. Hence, we decided to cross-culturally adapt and translate MSK-HQ to Marathi. Method We translated MSK-HQ score to Marathi (MSK-HQ-Ma) as per the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines. We tested its internal consistency, construct validity and reproducibility. It was compared with other health status scores EQ-5D-5L and overall health using the Visual Analogue Scale (VAS). Test-retest reliability was tested in those subjects who were having stable MSK health after two weeks. Results We recruited 158 consecutive subjects attending musculoskeletal clinics who had Marathi as their native language. Mean age was 44.8±17 years, females were 78 (49%). It showed good internal consistency (Cronbach's alpha = 0.95). For construct validity we found a strong correlation between MSK-HQ-Ma and EQ-5D-5L values (Spearman's r = 0.82, p<0.001). There was also a good correlation between MSK-HQ-Ma and overall health by VAS (Spearman's r = 0.76, p<0.001). An excellent test-retest reliability (Spearman's r = 0.94, p<0.001) was seen in 105 subjects who had stable MSK condition after two weeks of first appearance. Conclusion The MSK-HQ-Ma instrument has demonstrated good consistency, reliability and construct validity when evaluating the musculoskeletal health of individuals who can understand the Marathi language. Hence it can be used as a validated tool for the evaluation of musculoskeletal health in western India where Marathi is a commonly used language.

Incidence and Associated Factors of Postoperative Undesirable Anesthetic Outcomes Among Surgical Patients at Referral Hospitals in Amhara Region, Ethiopia: A Multi-Center Study

Background

Patients undergoing surgery frequently experience unfavorable anesthetic outcomes. They may have an impact on body systems and result in more serious postoperative morbidities. This study was conducted to determine the incidence of postoperative undesirable anesthetic outcomes among surgical patients at referral hospitals in Amhara region, Ethiopia.

Methods

A total of 412 patients, who underwent surgical procedures between August 1 and October 30 of 2022, were included in this study. The Leiden Perioperative Care Patient Satisfaction Questionnaire's (LPPSq) dimension "discomfort and needs" was used to collect data on the first postoperative day. Data entry and analysis were performed using SPSS version 20. To assess how risk factors affected the outcome variable, logistic regression analysis was utilized. In multivariable logistic regression analysis, a variable with a P-value of less than 0.05 was statistically considered as significant.

Results

The proportion of those who had "at least a little bit" of unfavorable outcomes was calculated to estimate their overall prevalence, and the prevalence of those who had "more than moderate" levels of unfavorable outcomes was determined to appreciate how severe these outcomes were. The percentages of postoperative pain, the most common undesired result, for "at least a little bit" and "more than moderate" were 87.7% and 32.3%, respectively. In this study, postoperative cold was the least prevalent (51.4%) undesirable anesthetic outcome. The remaining undesirable postoperative outcomes were reported less frequently.

Conclusion and Recommendation

Undesirable postoperative anesthetic outcomes were still common. The most frequent unfavorable result was postoperative pain. Adequate postoperative patient follow-up and quality service are paramount.

Prevalence of musculoskeletal pain among gynecologic surgeons performing laparoscopic procedures: A systematic review and meta-analysis

OBJECTIVE

Musculoskeletal discomfort is associated with repetitive movements and constrained body positions. The current meta-analysis was performed to determine the global prevalence of musculoskeletal symptoms among gynecologic surgeons who perform laparoscopy.

METHODS

Sources included Embase, MEDLINE, PubMed, CINAHL, Web of Science Core Collection, Cochrane Central Register of Controlled Clinical Trials, and Google Scholar. Articles published between 1980 and 2022 were considered. Studies that assessed self-reported musculoskeletal symptoms were included. Relevant data were extracted and tabulated.

RESULTS

Twelve studies met the inclusion criteria. In a pooled sample of 1619 surgeons, the estimated prevalence of musculoskeletal symptoms was 82% (95% confidence interval [CI], 70%-89%; I² , 92%). Female sex was a risk factor, as identified by a pooled odds ratio of 4.64 (95% CI, 2.63-8.19; I² , 0%) compared with male surgeons. Among surgeons who reported musculoskeletal symptoms, 30% (95% CI, 14%-52%; I² , 95%) sought treatment and 3% (95% CI, 2%-6%; I² , 0%) required work hour modifications.

CONCLUSION

The current meta-analysis provides preliminary evidence of a high prevalence of musculoskeletal symptoms among gynecologic laparoscopic surgeons. Future research is needed to explore the underlying risk factors and interventional strategies to mitigate this risk.

Modulation of central pain mechanisms using high-definition transcranial direct current stimulation: A double-blind, sham-controlled study

BACKGROUND

The use of high-definition transcranial direct current stimulation (HD-tDCS) has shown analgesic effects in some chronic pain patients, but limited anti-nociceptive effects in healthy asymptomatic subjects.

METHODS

This double-blinded sham-controlled study assessed the effects of HD-tDCS applied on three consecutive days on central pain mechanisms in healthy participants with (N = 40) and without (N = 40) prolonged experimental pain induced by intramuscular injection of nerve growth factor into the right hand on Day 1. Participants were randomly assigned to Sham-tDCS (N = 20 with pain, N = 20 without) or Active-tDCS (N = 20 with pain, N = 20 without) targeting simultaneously the primary motor cortex and dorsolateral prefrontal cortex for 20 min with 2 mA stimulation intensity. Central pain mechanisms were assessed by cuff algometry on the legs measuring pressure pain sensitivity, temporal summation of pain (TSP) and conditioned pain modulation (CPM), at baseline and after HD-tDCS on Day 2 and Day 3. Based on subject's assessment of received HD-tDCS (sham or active), they were effectively blinded.

RESULTS

Compared with Sham-tDCS, Active-tDCS did not significantly reduce the average NGF-induced pain intensity. Tonic pain-induced temporal summation at Day 2 and Day 3 was significantly lower in the NGF-pain group under Active-tDCS compared to the pain group with Sham-tDCS (p ≤ 0.05). No significant differences were found in the cuff pressure pain detection/tolerance thresholds or CPM effect across the 3 days of HD-tDCS in any of the four groups.

CONCLUSION

HD-tDCS reduced the facilitation of TSP caused by tonic pain suggesting that efficacy of HD-tDCS might depend on the presence of sensitized central pain mechanisms.

Abdominoplasty as an acute postoperative pain model: insights from 8 years of clinical trials

ABSTRACT

To have a complete understanding of an experimental analgesic's efficacy in treating acute postoperative pain, it is necessary to understand its effect on both hard-tissue pain and soft-tissue pain. For this reason, regulatory bodies including the U.S. Food and Drug Administration and European EMA typically require drug developers to demonstrate efficacy in both hard-tissue and soft-tissue pain to grant a broad approval for an analgesic in acute postoperative pain. Hard-tissue models such as bunionectomy and molar extraction are well-validated and efficient with long histories in clinical trials, but until recently, a similarly well-standardized and fast-enrolling soft-tissue model was not available. Abdominoplasty was developed as an acute postoperative pain model and introduced to the clinical trial marketplace in 2014 to address the need for a viable soft-tissue model. Since then, at least 13 industry-sponsored studies, including multiple pivotal trials, have been conducted, providing a data set that can be used to interrogate the model's strengths and weaknesses. The authors outline the development history of abdominoplasty, discuss key clinical and design characteristics of the model, and review public data from abdominoplasty acute pain studies available to date. The data suggest that abdominoplasty is a well-validated soft-tissue surgical model that provides high-quality experimental outputs, enabling the efficacy of investigational analgesics in soft-tissue pain to be understood successfully.

Researcher's Perspective on Musculoskeletal Conditions in Primary Care Physiotherapy Units through the International Classification of Functioning, Disability, and Health (ICF): A Scoping Review

(1) Background: Musculoskeletal disorders are the second cause of disability in the world. The International Classification of Functioning Disability and Health (ICF) is a tool for systematically describing functioning. Outcome measures for musculoskeletal disorders and functioning concepts embedded in them have not been described under the ICF paradigm. The objective of this scoping review was to identify ICF categories representing the researcher's perspective and to compare them with the ICF core set for post-acute musculoskeletal conditions. (2) Methods: This review was conducted as follows: (a) literature search using MEDLINE/PubMed, CINAHL, Web of Science, and Scopus databases; (b) study selection applying inclusion criteria (PICOS): musculoskeletal conditions in primary care, application of physiotherapy as a treatment, outcome measures related to functioning, and experimental or observational studies conducted in Western countries during the last 10 years; (c) extraction of relevant concepts; (d) linkage to the ICF; (e) frequency analysis; and (f) comparison with the ICF core set. (3) Results: From 540 studies identified, a total of 51 were included, and 108 outcome measures were extracted. In the ICF linking process, 147 ICF categories were identified. Analysis of data showed that 84.2% of the categories in the ICF core set for post-acute musculoskeletal conditions can be covered by the outcome measures analyzed. Sixty-eight relevant additional ICF categories were identified. (4) Conclusion: Outcome measures analyzed partially represent the ICF core set taken as a reference. The identification of additional categories calls into question the applicability of this core set in primary care physiotherapy units.

Repurposing existing products to accelerate injury recovery (REPAIR) of military relevant musculoskeletal conditions

Musculoskeletal injuries (MSKIs) are a great hindrance to the readiness of the United States Armed Forces through lost duty time and reduced operational capabilities. While most musculoskeletal injuries result in return-to-duty/activity with no (functional) limitations, the healing process is often long. Long healing times coupled with the high frequency of musculoskeletal injuries make them a primary cause of lost/limited duty days. Thus, there exists an urgent, clinically unmet need for interventions to expedite tissue healing kinetics following musculoskeletal injuries to lessen their impact on military readiness and society as a whole. There exist several treatments with regulatory approval for other indications that have pro-regenerative/healing properties, but few have an approved indication for treating musculoskeletal injuries. With the immediate need for treatment options for musculoskeletal injuries, we propose a paradigm of Repurposing Existing Products to Accelerate Injury Recovery (REPAIR). Developing treatments via repurposing existing therapeutics for other indications has shown monumental advantages in both cost effectiveness and reduced time to bring to market compared to novel candidates. Thus, undertaking the needed research efforts to evaluate the effectiveness of promising REPAIR-themed candidates has the potential to enable near-term solutions for optimizing musculoskeletal injuries recovery, thereby addressing a top priority within the United States. Armed Forces. Herein, the REPAIR paradigm is presented, including example targets of opportunity as well as practical considerations for potential technical solutions for the translation of existing therapeutics into clinical practice for musculoskeletal injuries.

Physical properties and biological effects of ceramic materials emitting infrared radiation for pain, muscular activity, and musculoskeletal conditions

BACKGROUND

Up to 33% of the general population worldwide suffer musculoskeletal conditions, with low back pain being the single leading cause of disability globally. Multimodal therapeutic options are available to relieve the pain associated with muscular disorders, including physical, complementary, and pharmacological therapies. However, existing interventions are not disease modifying and have several limitations.

METHOD

Literature review.

RESULTS

In this context, the use of nonthermal infrared light delivered via patches, fabrics, and garments containing infrared-emitting bioceramic minerals have been investigated. Positive effects on muscular cells, muscular recovery, and reduced inflammation and pain have been reported both in preclinical and clinical studies. There are several hypotheses on how infrared may contribute to musculoskeletal pain relief, however, the full mechanism of action remains unclear. This article provides an overview of the physical characteristics of infrared radiation and its biological effects, focusing on those that could potentially explain the mechanism of action responsible for the relief of musculoskeletal pain.

CONCLUSIONS

Based on the current evidence, the following pathways have been considered: upregulation of endothelial nitric oxide synthase, increase in nitric oxide bioavailability, anti-inflammatory effects, and reduction in oxidative stress.

Job stress and chronic and widespread musculoskeletal pain: a cross-sectional analysis from the Brazilian Longitudinal Study of Adult Health Musculoskeletal

ABSTRACT

Musculoskeletal pain is a global health concern, and work-related psychosocial stress might be a potential contributing factor. This cross-sectional study investigates whether job stress is associated with chronic and widespread musculoskeletal pain in 2051 Brazilian active civil servants included in the Brazilian Longitudinal Study of Adult Health Musculoskeletal (ELSA-Brasil MSK). Job stress was assessed using the Effort-Reward Imbalance (ERI) questionnaire. Associations between ERI domains, categorized into tertiles, and chronic musculoskeletal pain (CMP) at any site and per number of affected sites (0, 1-2, ≥3-multisite pain) and body regions (0, 1-2, 3-generalized pain), were investigated using binary and multinomial logistic regression, adjusted for sociodemographic, occupational, and health covariates. The prevalence of CMP at any site, multisites, and generalized regions was 52.9%, 18.2%, and 9.5%, respectively. After adjustments, the lower the reward and the greater the overcommitment, the higher the odds of CMP at any site. The ERI domains were more strongly associated with multisite and generalized CMP than with CMP at any site. Multisite CMP was associated with lower reward and with greater effort, overcommitment, and effort-reward imbalance ratio. Chronic musculoskeletal pain according to body regions, especially generalized pain, was also associated with ERI domains effort (OR = 2.06; 95%CI = 1.33-3.21), overcommitment (OR = 3.44; 95%CI = 2.20-5.39), and effort-reward imbalance ratio (OR = 2.06; 95%CI = 1.30-3.27). Results reveal an association between job stress not only with CMP at any site but notably with the pain spread to other body sites or regions. Our findings suggest that lowering stress at work and discouraging overcommitment may help reduce the CMP burden, including reduction of CMP spread from one site or region of the body to another.

Chronic pain, psychological distress, and quality of life in males with Duchenne muscular dystrophy

AIM

To describe chronic pain in Duchenne muscular dystrophy (DMD) from children's/adolescents' perspectives, explore patient variables associated with self-reported pain, and examine the relationship between chronic pain, psychological functioning, and health-related quality of life (HRQoL).

METHOD

This observational study included a paediatric cohort (aged 8-18 years; median age 9 years 4 months) with DMD under multidisciplinary care (n = 45). Clinical data of the latest visit were extracted from the electronic health record and assessment of pain, psychological distress, and HRQoL were performed during the same visit.

RESULTS

Thirty-two patients reported pain during the previous 4 weeks, and 18 reported persistent or recurrent chronic pain. Average pain intensity of chronic pain was mild, with regions of the legs (n = 12), lower back (n = 6), hips (n = 6), and shoulder (n = 6) most frequently affected. Older age, higher body mass index, being non-ambulatory, wheelchair dependency, and spinal deformities were contextual variables related to the presence of chronic pain. Furthermore, chronic pain was significantly associated with psychological distress and reduced HRQoL in paediatric patients with DMD.

INTERPRETATION

Chronic pain in paediatric DMD is frequent and widespread, highlighting the need for pain to be addressed in the routine care of affected young people. Chronic pain may make a significant contribution to psychological distress and impaired HRQoL in paediatric patients with DMD.

Features and methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a Delphi expert consensus study

ABSTRACT

Classification of musculoskeletal pain based on underlying pain mechanisms (nociceptive, neuropathic, and nociplastic pain) is challenging. In the absence of a gold standard, verification of features that could aid in discrimination between these mechanisms in clinical practice and research depends on expert consensus. This Delphi expert consensus study aimed to: (1) identify features and assessment findings that are unique to a pain mechanism category or shared between no more than 2 categories and (2) develop a ranked list of candidate features that could potentially discriminate between pain mechanisms. A group of international experts were recruited based on their expertise in the field of pain. The Delphi process involved 2 rounds: round 1 assessed expert opinion on features that are unique to a pain mechanism category or shared between 2 (based on a 40% agreement threshold); and round 2 reviewed features that failed to reach consensus, evaluated additional features, and considered wording changes. Forty-nine international experts representing a wide range of disciplines participated. Consensus was reached for 196 of 292 features presented to the panel (clinical examination-134 features, quantitative sensory testing-34, imaging and diagnostic testing-14, and pain-type questionnaires-14). From the 196 features, consensus was reached for 76 features as unique to nociceptive (17), neuropathic (37), or nociplastic (22) pain mechanisms and 120 features as shared between pairs of pain mechanism categories (78 for neuropathic and nociplastic pain). This consensus study generated a list of potential candidate features that are likely to aid in discrimination between types of musculoskeletal pain.

Fitness Trainers' Educational Qualification and Experience and Its Association with Their Trainees' Musculoskeletal Pain: A Cross-Sectional Study

This is a cross-sectional study that examined the association between fitness trainers’ educational qualifications and experience, and the risk of their trainees’ musculoskeletal pain. The study included 1177 trainees (aged 15−60 years) from 74 fitness centers in Bangladesh. Data were collected by using the Nordic musculoskeletal questionnaire, including potential confounders such as demographic factors (e.g., age, occupation), and training-related factors (e.g., workout knowledge, overweight lifting). Multiple logistic regression was performed for a binary outcome (pain—yes or no), and a generalized linear model was fitted for the ordinal outcome (pain—sites of the body). The trainers’ lower experience (no or ≤1 year) was associated with higher odds of their trainees’ musculoskeletal pain (OR: 2.53, 95% CI: 1.18−5.44) compared to trainers with >5 years of experience; however, no association was found between the trainers’ education and the risk of their trainees’ musculoskeletal pain, after controlling for potential confounders. Similarly, the trainees trained by trainers with lower experience had more than two-time the risk of having pain in different sites (IRR: 2.04, 95% CI: 1.50−2.79). The trainers’ experience may play a pivotal role in the trainees’ musculoskeletal pain. Further study is warranted in this regard.

Preference of Orthopedic Practitioners Toward the Use of Topical Medicine for Musculoskeletal Pain Management in China: A National Survey

OBJECTIVE

Musculoskeletal pain is having growing impacts worldwide with clinical challenge in pain management. The purpose of the present study is to investigate the preferences of orthopedic surgeons of China for using medicine in musculoskeletal pain.

METHODS

A questionnaire was developed, including the following domains, personal information, medication preference for pain treatment, and perceptions of topical medicine. Ten participants were selected to confirm the consistency of questionnaire. A cross-sectional survey was conducted in orthopedic physicians with different specialties in different regions of China via the online survey platform. The participants' survey results were analyzed one-way and multi-way using chi-square test and logistic regression.

RESULTS

The pre-survey analysis results of 10 randomly selected investigators were a mean weighted kappa coefficient of 0.76 (range 0.61-0.89), which indicated the substantial consistency of the present questionnaire. A total of 1099 orthopedic surgeons (mean age, 41.67 ± 8.31 years) responded to our survey, most of whom were male (90.72%), and most of whom worked in level III hospitals (63.24%) and trained in modern medicine (71.43%). Most surgeons who participated in the survey had used topical analgesics in their clinical work (95.81%), and most preferred to use topical analgesics (39.50%) or a combination of oral analgesics (28.87%). Primary reasons for preferring topical analgesics were as follows: less adverse reactions (68.01%); ease of use (60.90%); and not interfering with other oral medications (49.60%). The preference for prescribing topical analgesics increased with the education level of the respondent, where statistically significant differences were seen (P < 0.05). In addition, the level of the respondent's hospital, type of hospital, the respondent's profession, and their participation in surgical work influenced their preferences for topical analgesics (P < 0.05).

CONCLUSION

Orthopedic surgeons across China have different medication preferences in the treatment of musculoskeletal pain. The educational background of the physician largely influences the preference when selecting medications. To better improve the treatment of musculoskeletal pain, there is a need to improve the overall medical education of practitioners and to disseminate clinical practice guidelines.

Tendinopathies and Pain Sensitisation: A Meta-Analysis with Meta-Regression

The presence of pain sensitisation has been documented and reported as being a possible cause of treatment failure and pain chronicity in several musculoskeletal conditions, such as tendinopathies. The aim of the present study is to analyse existing evidence on pain sensitisation in tendinopathies comparing the local and distant pain thresholds of healthy and affected subjects with distinct analysis for different tendinopathies. PubMed, Cochrane Central Register, Scopus, and Web Of Science were systematically searched after registration on PROSPERO (CRD42020164124). Level I to level IV studies evaluating the presence of pain sensitisation in patients with symptomatic tendinopathies, documented through a validated method, were included. A meta-analysis was performed to compare local, contralateral, and distant pain thresholds between patients and healthy controls with sub-analyses for different tendinopathies. Meta-regressions were conducted to evaluate the influence of age, activity level, and duration of symptoms on results. Thirty-four studies out of 2868 were included. The overall meta-analysis of local pressure pain thresholds (PPT) documented an increased sensitivity in affected subjects (p < 0.001). The analyses on contralateral PPTs (p < 0.001) and distant PPTs (p = 0.009) documented increased sensitivity in the affected group. The results of the sub-analyses on different tendinopathies were conflicting, except for those on lateral epicondylalgia. Patients’ activity level (p = 0.02) and age (p = 0.05) significantly influenced local PPT results. Tendinopathies are characterized by pain sensitisation, but, while features of both central and peripheral sensitisation can be constantly detected in lateral epicondylalgia, results on other tendinopathies were more conflicting. Patients’ characteristics are possible confounders that should be taken into account when addressing pain sensitisation.

Interhemispheric Inhibition Between Primary Sensory Cortices is not Influenced by Acute Muscle Pain

Bilateral deficits in sensorimotor function have been observed in unilateral musculoskeletal pain conditions. Altered interhemispheric inhibition (IHI) between primary sensory cortices (S1s) is one mechanism that could explain this phenomenon. However, IHI between S1s in response to acute muscle pain, and the relationship between IHI and pressure pain sensitivity in the unaffected limb have not been examined. In 21 healthy individuals, IHI was assessed using somatosensory evoked potentials in response to paired median nerve electrical stimulation at: 1) baseline; 2) immediately following pain resolution; and 3) at 30-minutes follow-up. Acute muscle pain was induced by injection of hypertonic saline into the right abductor pollicis brevis (APB) muscle. Pressure pain thresholds were assessed at the right and left APB muscles before and 30-minutes after pain resolution. Compared to baseline, IHI from the affected to unaffected S1 was unaltered in response to acute muscle pain immediately following pain resolution, or at 30-minutes follow-up. Pressure pain thresholds were reduced over the right (P = .001) and left (P = .001) APB muscles at 30-minutes follow-up. These findings suggest IHI between S1s is unaffected by acute, short-lasting muscle pain, despite the development of increased sensitivity to pressure in the unaffected APB muscle. PERSPECTIVE: IHI from the affected S1 (contralateral to the side of pain) to unaffected S1 is unaltered following the resolution of acute muscle pain. This finding suggests that IHI between S1s may not be relevant in the development of bilateral sensorimotor symptoms in unilateral pain conditions.

Does your sleeping position affect your shoulder pain?

Aim: This study aimed to evaluate patients with shoulder pain according to their sleeping positions based on their clinical and magnetic resonance imaging (MRI) findings and to determine possible factors affecting shoulder pain. Material and Method: A total of 115 patients were included in the study. The severity of shoulder pain was evaluated with the visual analog scale (VAS), shoulder function was evaluated with the simple shoulder test, and the ability to perform physical activities was evaluated with the QuickDASH questionnaire. The biceps tendon, rotator cuff (RC), subacromial-subdeltoid bursa, glenohumeral joint (GHJ), and acromioclavicular joint (ACJ) were evaluated using MRI. Results: Of the patients with shoulder pain, 66.1% were female, 50.4% were primary school graduates, 53.9% were housewives, and 41.7% had a systemic disease. The mean age of the patients was 50.48±13.61 years while the median BMI and VAS values were 26.1 (18.2-41.4) and 8 (2-10), respectively. Considering the sleeping positions, it was found that 39.1% (most common) of the patients were sleeping in the fetus position, and considering the results of patients’ MRI examinations, the most common problem was related to the pathologies of the supraspinatus tendon (42.6%). It was found that sleep quality, which was poor in all patients, was worse in females (p=0.311), in those over 50 years of age (p=0.007), and those with a systemic disease (0.325). It was discovered that Pittsburgh's sleep quality index score was generally worse in those who slept in the soldier position and in the log position (p>0.05). The rates of pathologies of the supraspinatus tendon were found to be the highest in those that slept in the fetus position (p=0.931). It was also found that the rates of impingement, bicipital tendinitis, combined problems, and adhesive capsulitis did not differ significantly according to sleeping positions. Although occupational variables for supraspinatus degeneration remained significant in the model, having a desk job statistically significantly increased the probability of supraspinatus degeneration by 3.38 times when compared to being a housewife (95% CI=1.143-9.996; p=0.028) and it was identified that the probability of acromioclavicular degeneration increased by 1.16 times for every 1-unit increase in BMI. Conclusion: Different sleeping positions may predispose to different shoulder pathologies and shoulder pain, and shoulder pathologies may lead to deterioration of sleep quality, especially in older patients. For this reason, suggesting correct and appropriate sleeping positions may be a useful treatment method in reducing pain and disability and increasing sleep quality.

Chronic Musculoskeletal Pain Moderates the Association between Sleep Quality and Dorsostriatal-Sensorimotor Resting State Functional Connectivity in Community-Dwelling Older Adults

Aging is associated with poor sleep quality and greater chronic pain prevalence, with age-related changes in brain function as potential underlying mechanisms. Objective. The following cross-sectional study aimed to determine whether self-reported chronic musculoskeletal pain in community-dwelling older adults moderates the association between sleep quality and resting state functional brain connectivity (rsFC). Methods. Community-dwelling older individuals (mean age = 73.29 years) part of the NEPAL study who completed the Pittsburg Sleep Quality Index (PSQI) and a rsFC scan were included (n = 48) in the present investigation. To that end, we tested the effect of chronic pain-by-PSQI interaction on rsFC among atlas-based brain regions-of-interest, controlling for age and sex. Results and Discussion. A significant network connecting the bilateral putamen and left caudate with bilateral precentral gyrus, postcentral gyrus, and juxtapositional lobule cortex, survived global multiple comparisons (FDR; q < 0.05) and threshold-free network-based-statistics. Greater PSQI scores were significantly associated with greater dorsostriatal-sensorimotor rsFC in the no-pain group, suggesting that a state of somatomotor hyperarousal may be associated with poorer sleep quality in this group. However, in the pain group, greater PSQI scores were associated with less dorsostriatal-sensorimotor rsFC, possibly due to a shift of striatal functions toward regulation sensorimotor aspects of the pain experience, and/or aberrant cortico-striatal loops in the presence of chronic pain. This preliminary investigation advances knowledge about the neurobiology underlying the associations between chronic pain and sleep in community-dwelling older adults that may contribute to the development of effective therapies to decrease disability in geriatric populations.

Spatiotemporal patterns of pain distribution and recall accuracy: a dose-response study

OBJECTIVES

Clinical decisions rely on a patient's ability to recall and report their pain experience. Monitoring pain in real-time (momentary pain) may reduce recall errors and optimize the clinical decision-making process. Tracking momentary pain can provide insights into detailed changes in pain intensity and distribution (area and location) over time. The primary aims of this study were (i) to measure the temporal changes of pain intensity, area, and location in a dose-response fashion and (ii) to assess recall accuracy of the peak pain intensity and distribution seven days later, using a digital pain mapping application. The secondary aims were to (i) evaluate the influence of repeated momentary pain drawings on pain recall accuracy and (ii) explore the associations among momentary and recall pain with psychological variables (pain catastrophizing and perceived stress).

METHODS

Healthy participants (N=57) received a low (0.5 ml) or a high (1.0 ml) dose of hypertonic saline (5.8%) injection into the right gluteus medius muscle and, subsequently, were randomized into a non-drawing or a drawing group. The non-drawing groups reported momentary pain intensity every 30-s. Whereas the drawing groups reported momentary pain intensity and distribution on a digital body chart every 30-s. The pain intensity, area (pixels), and distribution metrics (compound area, location, radiating extent) were compared at peak pain and over time to explore dose-response differences and spatiotemporal patterns. All participants recalled the peak pain intensity and the peak (most extensive) distribution seven days later. The peak pain intensity and area recall error was calculated. Pain distribution similarity was determined using a Jaccard index which compares pain drawings representing peak distribution at baseline and recall. The relationships were explored among peak intensity and area at baseline and recall, catastrophizing, and perceived stress.

RESULTS

The pain intensity, area, distribution metrics, and the duration of pain were lower for the 0.5 mL than the 1.0 mL dose over time (p<0.05). However, the pain intensity and area were similar between doses at peak pain (p>0.05). The pain area and distribution between momentary and recall pain drawings were similar (p>0.05), as reflected in the Jaccard index. Additionally, peak pain intensity did not correlate with the peak pain area. Further, peak pain intensity, but not area, was correlated with catastrophizing (p<0.01).

CONCLUSIONS

This study showed differences in spatiotemporal patterns of pain intensity and distribution in a dose-response fashion to experimental acute low back pain. Unlike pain intensity, pain distribution and area may be less susceptible in an experimental setting. Higher intensities of momentary pain do not appear to influence the ability to recall the pain intensity or distribution in healthy participants.

IMPLICATIONS

The recall of pain distribution in experimental settings does not appear to be influenced by the intensity despite differences in the pain experience. Pain distribution may add additional value to mechanism-based studies as the distribution reports do not vary with pain catastrophizing. REC# N-20150052.

Telerehabilitation of acute musculoskeletal multi-disorders: prospective, single-arm, interventional study

Background

Acute musculoskeletal (MSK) pain is very common and associated with impaired productivity and high economic burden. Access to timely and personalized, evidence-based care is key to improve outcomes while reducing healthcare expenditure. Digital interventions can facilitate access and ensure care scalability.

Objective

Present the feasibility and results of a fully remote digital care program (DCP) for acute MSK conditions affecting several body areas.

Methods

Interventional single-arm study of individuals applying for digital care programs for acute MSK pain. Primary outcome was the mean change between baseline and end-of-program in self-reported Numerical Pain Rating Scale (NPRS) score and secondary outcomes were change in analgesic consumption, intention to undergo surgery, anxiety (GAD-7), depression (PHQ-9), fear-avoidance beliefs (FABQ-PA), work productivity (WPAI-GH) and engagement.

Results

Three hundred forty-three patients started the program, of which 300 (87.5%) completed the program. Latent growth curve analysis (LGCA) revealed that changes in NPRS between baseline and end-of-program were both statistically (p < 0.001) and clinically significant: 64.3% reduction (mean − 2.9 points). Marked improvements were also noted in all secondary outcomes: 82% reduction in medication intake, 63% reduction in surgery intent, 40% in fear-avoidance beliefs, 54% in anxiety, 58% in depression and 79% recovery in overall productivity. All outcomes had steeper improvements in the first 4 weeks, which paralleled higher engagement in this period (3.6 vs 3.2 overall weekly sessions, p < 0.001). Mean patient satisfaction score was 8.7/10 (SD 1.26).

Strengths and limitations

This is the first longitudinal study demonstrating the feasibility of a DCP for patients with acute MSK conditions involving several body areas. Major strengths of this study are the large sample size, the wide range of MSK conditions studied, the breadth of outcomes measured, and the very high retention rate and adherence level. The major limitation regards to the absence of a control group.

Conclusions

We observed very high completion and engagement rates, as well as clinically relevant changes in all health-related outcomes and productivity recovery. We believe this DCP holds great potential in the delivery of effective and scalable MSK care.

Trial registration

NCT, NCT04092946. Registered 17/09/2019;

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04891-5.

Quantitative sensory testing: identifying pain characteristics in patients with osteoarthritis

OBJECTIVE

This review outlines the most commonly used quantitative sensory tests to identify pain sensitization. We examine cross-sectional associations between quantitative sensory testing (QST) measures and OA symptoms and severity, along with longitudinal associations between QST findings and response to surgical and non-surgical treatments for OA.

DESIGN

We conducted a search in PubMed for English language papers including 'osteoarthritis' and 'quantitative sensory testing' as search terms. Papers that did not pertain specifically to OA or QST were excluded.

RESULTS

Pressure Pain Threshold (PPT), Conditioned Pain Modulation (CPM), and Temporal Summation (TS) are the QST measures used most frequently to identify pain sensitization. Findings indicate that persons with knee OA often exhibit lower PPT thresholds, inefficient CPM, and facilitated TS as compared with controls who do not have OA, supporting the discriminant validity of QST. Pre-treatment QST has shown some success in identifying persons who experience less pain relief from surgical and non-surgical treatments for knee OA. Post-treatment QST has shown that sometimes PPT and CPM can normalize (PPT thresholds increase, and CPM becomes efficient) in patients for whom joint replacement is successful. Recent studies indicate that QST measures are more closely associated with pain severity than OA radiographic severity, suggesting that sensitization may be a trait rather than a state.

CONCLUSIONS

QST may have a role in identifying persons who are susceptible to chronic pain and may offer an opportunity for personalized, more effective treatment of OA.

Acid-sensing ion channel 3: An analgesic target

Acid-sensing ion channel 3 (ASIC3) belongs to the epithelial sodium channel/degenerin (ENaC/DEG) superfamily. There are 7 different ASIC subunits encoded by 5 different genes. Most ASIC subunits form trimeric ion channels that upon activation by extracellular protons mediate a transient inward current inducing cellular excitability. ASIC subunits exhibit differential tissue expression and biophysical properties, and the ability of subunits to form homo- and heteromeric trimers further increases the complexity of currents measured and their pharmacological properties. ASIC3 is of particular interest, not only because it exhibits high expression in sensory neurones, but also because upon activation it does not fully inactivate: a transient current is followed by a sustained current that persists during a period of extracellular acidity, i.e. ASIC3 can encode prolonged acidosis as a nociceptive signal. Furthermore, certain mediators sensitize ASIC3 enabling smaller proton concentrations to activate it and other mediators can directly activate the channel at neutral pH. Moreover, there is a plethora of evidence using transgenic mouse models and pharmacology, which supports ASIC3 as being a potential target for development of analgesics. This review will focus on current understanding of ASIC3 function to provide an overview of how ASIC3 contributes to physiology and pathophysiology, examining the mechanisms by which it can be modulated, and highlighting gaps in current understanding and future research directions.

Bedside clinical tests to assess sensitization in office workers with chronic neck pain

OBJECTIVE

This study aimed to assess pain sensitization in individual office workers with chronic neck pain through simple bedside quantitative sensory tests (QST) and to associate the findings with pain intensity and pain catastrophizing.

METHODS

One hundred-and-four office workers with chronic neck pain were assessed using pressure pain threshold (PPT) considering pain sensitive if PPTs were lower than 155 kPa in the upper trapezius and 245 kPa in the tibialis anterior. Pain sensitive to temporal summation of pain (TSP) was considered if there was a difference of two points in the visual analogue scale (VAS) comparing the first and last stimulus. Pain sensitive was considered to conditioned pain modulation (CPM) if the CPM-effect was less than -7.5%. Pain intensity and catastrophizing were measured using VAS and with the Pain Catastrophizing Scale.

RESULTS

There was at least one pain sensitive QST finding in 66 office workers (63.5%). TSP findings were the most common (48.1%), followed by PPT's (31.7%) and CPM (20.2%). Based on the QST findings, office workers were divided based on the number of individual QST findings, and higher pain intensity and pain catastrophizing scores were found in office workers with one (N = 38, P < 0.05) or two (N = 28, P < 0.05) compared with office workers with no QST findings (N = 38).

CONCLUSION

This study demonstrated that most office workers with chronic neck pain exhibit either widespread pressure hyperalgesia, facilitated TSP or impaired CPM, indicating pain sensitization within the central nervous system. This was associated with increased clinical pain and pain catastrophizing rumination scores.

Current Treatment Options for Patients with Myotonic Dystrophy Type 2

Purpose of the review

Myotonic dystrophy types 1 and 2 are frequent forms of muscular dystrophies in adulthood. Their clinical differences need to be taken into account for the most appropriate treatment of patients. The aim of this article is to provide an overview on the current and upcoming therapeutic options for patients with myotonic dystrophy type 2 (DM2).

Recent findings

At the moment, no disease-modifying therapies are available for DM2; next-generation therapies may however be available in the near future. In the meanwhile, the symptomatic management of patients has greatly improved, thank to the production of consensus-based standards of care and the growing evidence of efficacy of anti-myotonic drugs, promising employment of cannabinoids for symptom’s relief, regular monitoring, and early detection of treatable extra-muscular manifestations.

Summary

The treatment of DM2 is currently symptomatic and relies on the coordinated intervention of a multidisciplinary team. It remains to be determined whether upcoming causal therapies for myotonic dystrophy type 1 will be applicable also in DM2.

Self-Healing: A Concept for Musculoskeletal Body Pain Management - Scientific Evidence and Mode of Action

Traditionally, musculoskeletal pain management has focused on the use of conventional treatments to relieve pain. However, multi-modal integrative medicine including alternative/complementary treatments is becoming more widely used and integrated into treatment guidelines around the world. The uptake of this approach varies according to country, with generally a higher uptake in developed countries and in females aged more than 40 years. Integral to the concept described here, is that the body has an innate ability to self-heal, which can be optimized by the use of integrative medical strategies. Stress triggers for acute or recurring musculoskeletal pain are diverse and can range from physical to psychological. The mechanism by which the body responds to triggers and initiates the self-healing processes is complex, but five body networks or processes are thought to be integral: the nervous system, microcirculation/vasodilation, immune modulation, muscular relaxation/contraction and psychological balance. Multi-modal integrative medicine approaches include nutritional/dietary modification, postural/muscular training exercises, and cognitive behavioral mind/body techniques. This article will review the self-healing concept and provide plausible scientific evidence where available.

High Rate of Pain Sensitization in Musculoskeletal Shoulder Diseases: A Systematic Review and Meta-analysis

BACKGROUND

Pain sensitization, defined as an increased responsiveness of nociceptive neurons to normal input, is detected in several musculoskeletal diseases, but there are no systematic reviews or meta-analyses about pain sensitization in shoulder pain.

OBJECTIVES

The aim of the study was to document pain sensitization rate and its impact in patients with shoulder pain.

MATERIALS AND METHODS

PubMed, Cochrane Library, and Web of Science were searched on January 8, 2020. Level I-IV studies, evaluating pain sensitization in musculoskeletal shoulder disorders through validated methods (questionnaires/algometry) were included. The primary outcome was pain sensitization rate. Secondary outcomes were the pain sensitivity level measured as pressure pain threshold, temporal summation, conditioned pain modulation, and suprathreshold heat pain response. Associated demographic and psychosocial factors were evaluated.

RESULTS

The rate of abnormal pressure pain threshold in patients with shoulder pain varied from 29% to 77%. Questionnaires detected pain sensitization in 11% to 24% of patients. This meta-analysis showed no difference in pressure pain threshold and central pain modulation but documented a significant difference in terms of suprathreshold heat pain response, indicating a hypersensitivity state in patients with shoulder pain versus asymptomatic controls. The only factor that was constantly found to correlate with higher sensitivity was a lower postoperative outcome.

DISCUSSION

Pain sensitization has a high rate among patients with musculoskeletal shoulder pain, regardless of the specific etiology, and this may lead to worse clinical outcome after treatment of the primary disease. The best way to assess pain sensitization still needs to be identified as the assessment methods results in used high variability in the documented pain sensitization rate.

Sensitization in office workers with chronic neck pain in different pain conditions and intensities

OBJECTIVES

Office workers with chronic neck pain demonstrates signs of widespread hyperalgesia, less efficient descending pain modulation, which could indicate sensitization of central pain pathways. No studies have assessed a wide variety of office workers with different chronic neck pain disorders and assessed the impact of pain intensity on assessments of central pain pathways. This study aimed to assessed pressure pain thresholds (PPTs), temporal summation of pain (TSP) and conditioned pain modulation (CPM) and to associate these with pain intensity and disability in subgroups of office workers.

METHODS

One hundred-and-seventy-one office workers were distributed into groups of asymptomatic and chronic neck pain subjects. Chronic neck pain was categorized as chronic trapezius myalgia and chronic non-specific neck pain and as 'mild-pain' (Visual Analog Scale [VAS]≤3) and 'moderate-pain' (VAS>3) groups. PPTs, TSP, CPM, and Copenhagen Psychosocial Questionnaire II were assessed in all subjects. Neck Disability Index and Pain Catastrophizing Scale were assessed in all the symptomatic office workers.

RESULTS

PPTs were lower in moderate pain (n=49) and chronic trapezius myalgia (n=56) compared with asymptomatic subjects (n=62, p<0.05). TSP was facilitated in moderate pain group compared with mild pain (n=60, p<0.0001) group and asymptomatic subjects (p<0.0001). No differences were found in CPM comparing the different groups (p<0.05). Multiple regression analysis identified Neck Disability Index and TSP as independent factors for prediction of pain intensity in chronic trapezius myalgia (R²=0.319) and chronic non-specific neck pain (R²=0.208). Somatic stress, stress and sleep as independent factors in chronic non-specific neck pain (R²=0.525), and stress in moderate pain group (R²=0.494) for the prediction of disability.

CONCLUSIONS

Office workers with chronic trapezius myalgia and moderate pain intensity showed significant signs of widespread pressure hyperalgesia. Moreover, the moderate pain group demonstrated facilitated TSP indicating sensitization of central pain pathways. Neck Disability Index and TSP were independent predictors for pain intensity in pain groups. Sleep and stress were independent predictors for disability.

Applying the NIA Health Disparities Research Framework to Identify Needs and Opportunities in Chronic Musculoskeletal Pain Research

Disparities in the experience of chronic musculoskeletal pain in the United States stem from a confluence of a broad array of factors. Organized within the National Institute on Aging Health Disparity Research Framework, a literature review was completed to evaluate what is known and what is needed to move chronic musculoskeletal pain research forward specific to disproportionately affected populations. Peer-reviewed studies published in English, on human adults, from 2000 to 2019, and conducted in the United States were extracted from PubMed and Web of Science. Articles were reviewed for key words that focused on underrepresented ethnic/race groups with chronic musculoskeletal pain applying health factor terms identified in the NIAHealth Disparity Research Framework four levels of analysis: 1) environmental, 2) sociocultural, 3) behavioral, and 4) biological. A total of 52 articles met inclusion criteria. There were limited publications specific to underrepresented ethnic/race groups with chronic musculoskeletal pain across all levels with particular research gaps under sociocultural and biological categories. Current limitations in evidence may be supplemented by a foundation of findings specific to the broader topic of "chronic pain" which provides guidance for future investigations. Study designs including a focus on protective factors and multiple levels of analyses would be particularly meritorious. PERSPECTIVE: Chronic musculoskeletal pain unequally burdens underrepresented ethnic/race groups. In order to move research forward and to systematically investigate the complex array of factors contributing toward health disparities, an organized approach is necessary. Applying the NIA Health Disparities Research Framework, an overview of the current state of evidence specific to chronic musculoskeletal pain and underrepresented ethnic/race groups is provided with future directions identified.

Effect of anodal high-definition transcranial direct current stimulation on the pain sensitivity in a healthy population: a double-blind, sham-controlled study

ABSTRACT

High-definition transcranial direct current stimulation (HD-tDCS) of brain areas related to pain processing may provide analgesic effects evident in the sensory detection and pain thresholds. The somatosensory sensitivity was assessed after HD-tDCS targeting the primary motor cortex (M1) and/or the dorsolateral prefrontal cortex (DLPFC). Eighty-one (40 females) subjects were randomly assigned to 1 of 4 anodal HD-tDCS protocols (20 minutes) applied on 3 consecutive days: Sham-tDCS, DLPFC-tDCS, M1-tDCS, and DLPFC&M1-tDCS (simultaneous transcranial direct current stimulation [tDCS] of DLPFC and M1). Subjects and experimenter were blinded to the tDCS protocols. The somatosensory sensitivity were assessed each day, before and after each tDCS by detection and pain thresholds to thermal and mechanical skin stimulation, vibration detection thresholds, and pressure pain thresholds. Subjects were effectively blinded to the protocol, with no significant difference in rates of whether they received real or placebo tDCS between the 4 groups. Compared with the Sham-tDCS, none of the active HD-tDCS protocols caused significant changes in detection or pain thresholds. Independent of tDCS protocols, pain and detection thresholds except vibration detection were increased immediately after the first tDCS protocol compared with baseline (P < 0.05). Overall, the active stimulation protocols were not able to induce significant modulation of the somatosensory thresholds in this healthy population compared with sham-tDCS. Unrelated to the HD-tDCS protocol, a decreased sensitivity was found after the first intervention, indicating a placebo effect or possible habituation to the quantitative sensory testing assessments. These findings add to the increasing literature of null findings in the modulatory effects of HD-tDCS on the healthy somatosensory system.

Pressure pain thresholds in office workers with chronic neck pain: A systematic review and meta-analysis

OBJECTIVES

The purpose of this study was to (a) compare pressure pain threshold (PPT) values between office workers with chronic neck pain and asymptomatic controls; (b) establish reference PPT values in chronic neck pain; and (c) evaluate associations between PPTs and pain intensity, and disability.

METHODS

Seven English/Portuguese databases were searched for relevant literature. Studies investigating adult office workers (age >18 years) with chronic neck pain were included if PPTs were an outcome. The risk of bias was assessed using the Downs and Black checklist. Meta-analysis was conducted if a cluster contained at least two studies reporting the same PPTs.

RESULTS

Ten high quality, two low quality, and one poor quality studies were included. The meta-analysis revealed decreased PPT values in the upper trapezius, extensor carpi ulnaris, and tibialis anterior in office workers with chronic neck pain when compared with healthy workers, without a statistical difference (p > 0.05). The PPT reference value in the upper trapezius was 263 kPa (95% confidence interval [CI] = 236.35 to 289.70), and 365 kPa (95% CI = 316.66 to 415.12) for the tibialis anterior in office workers with chronic neck pain. No correlations were found between the upper trapezius PPT and pain intensity and disability.

CONCLUSION

This meta-analysis found that all the PPT measurements were not significantly reduced in office workers with chronic neck pain compared with healthy workers. These assumptions were based on a small sample of existing studies, and therefore further studies are necessary to quantify the differences in PPTs. Hypersensitivity PPT reference values are proposed for localized and extrasegmental sites in office workers with chronic neck pain.

Navigating diagnostic uncertainty in musculoskeletal practice: The perspectives and experiences of new graduate physiotherapists

BACKGROUND

Diagnostic uncertainty in musculoskeletal pain presents as a frequent and challenging dilemma encountered by health professionals. Current literature indicates that diagnostic uncertainty impacts the clinical decision making of experienced physiotherapists. Despite this, the experiences and navigational strategies of new graduate physiotherapists, pertaining to this dilemma, are widely unknown.

OBJECTIVES

The aim of this study was to explore how new graduate physiotherapists experience and navigate diagnostic uncertainty when managing individuals with musculoskeletal pain.

METHODS

A qualitative study using a thematic analytical research approach was undertaken. A randomized sample of new graduate physiotherapists, working in musculoskeletal settings (n = 17), participated in semi-structured telephone interviews. Interview data was subsequently subject to thematic analysis.

RESULTS

Four key themes emerged from the data: 1) diagnostic uncertainty is fraught with challenges; 2) diagnosis is not the end game; 3) intrinsic strategies and extrinsic actions and 4) the imperative role of clinical practice.

CONCLUSION

New graduate physiotherapists frequently experience diagnostic uncertainty within musculoskeletal practice and are commonly challenged by this dilemma. Despite this, new graduates utilize several strategies to mitigate challenges including focusing on patient-centered care, maintaining transparency and relying on senior colleagues. Most strategies are directly attributed to clinical experiences. This study further outlines implications for physiotherapy curricula and workplace support.

Treatment of chronic musculoskeletal pain with electron modulation procedure

Aim: To assess the efficacy of the electron modulation procedure (EMP) in reducing chronic musculoskeletal pain acutely over distinct anatomical areas. Materials & methods: We performed a retrospective analysis of 223 patients who received a single EMP treatment for various chronic musculoskeletal pain issues. Pain levels, recorded before and after receiving EMP, were analyzed at distinct anatomical musculoskeletal areas. Results & conclusion: The effect of the EMP treatments in reducing musculoskeletal pain was statistically significant at the 5% level. Those with hip/gluteal and ankle pain had the highest (92%) and lowest (58%) pain elimination rate, respectively. Statistical evidence supported the idea that EMP treatment can quickly reduce musculoskeletal pain. Distinct anatomical musculoskeletal areas responded differently to EMP treatment.

Simple vacuum cup to identify the primary myofascial restriction: the root cause of pain elsewhere

Identification of the primary source of pain determines the success of musculoskeletal pain management. A detailed history and physical examination are the current gold standards for identifying musculoskeletal pain source in day-to-day clinical practice. This process, at times, may potentially result in inadequate/inappropriate identification of the pain source. In this case report, we present the usefulness of a simple and inexpensive vacuum cup. We found that this accurately identified the primary pain source, distant from and unrelated to the site of pain presentation in a 30-year-old man with back pain. Routine use of this simple technique in conjunction with the regular musculoskeletal examination may better identify primary restrictions in the body tissues. Based on our experience, we propose that this approach has the potential to offer better outcomes in the treatment of musculoskeletal pain in the future.

The Prevalence and Factors Associated with Musculoskeletal Pain Among Pilgrims During the Hajj

BACKGROUND

Musculoskeletal pain is a primary burden on individuals as well as social and health care systems. Annually, 2-3 million pilgrims perform the Hajj in Mecca, Saudi Arabia. The Hajj is highly physically demanding because pilgrims generally move by foot for long distances among a series of religious sites, an effort that may exceed their typical levels of physical activity. To understand the impact of musculoskeletal pain on the completion of the Hajj, it is first necessary to evaluate the extent of the problem. Accordingly, this study aimed to estimate the prevalence of musculoskeletal pain and associated factors among pilgrims during the Hajj.

METHODS

A cross-sectional survey was conducted during the period of the Hajj. The participants were adult pilgrims ≥ 18 years of age. Data regarding demographics, the prevalence of falls and the point prevalence of musculoskeletal pain by anatomical site were recorded. Participants were allowed to report more than one site of pain. Prevalence, crude and adjusted risk ratios were calculated.

RESULTS

A total of 1715 pilgrims were included in the analysis. The prevalence of falls was 13.76%. The prevalence of overall musculoskeletal pain (pain at any site) was 80.46%. Musculoskeletal pain was most commonly reported in the ankle/foot (38.34%), leg (29.89%), lower back (28.47%) and knee (21.84%). In general, musculoskeletal pain at multiple sites was more common in females and in older and obese individuals. However, there were variations in the importance of sex, age and body mass index as associated factors across different pain sites.

CONCLUSION

Musculoskeletal pain is common among pilgrims. Unlike most populations examined in other studies, ankle/foot pain was the most common in pilgrims. These data provide guidance for potential preventative programs and the allocation of resources to optimize pilgrims' experiences and ability to complete the Hajj.

Characterization of Source-Localized EEG Activity During Sustained Deep-Tissue Pain

Musculoskeletal pain is a clinical condition that is characterized by ongoing pain and discomfort in the deep tissues such as muscle, bones, ligaments, nerves, and tendons. In the last decades, it was subject to extensive research due to its high prevalence. Still, a quantitative description of the electrical brain activity during musculoskeletal pain is lacking. This study aimed to characterize intracranial current source density (CSD) estimations during sustained deep-tissue experimental pain. Twenty-three healthy volunteers received three types of tonic stimuli for three minutes each: computer-controlled cuff pressure (1) below pain threshold (sustained deep-tissue no-pain, SDTnP), (2) above pain threshold (sustained deep-tissue pain, SDTP) and (3) vibrotactile stimulation (VT). The CSD in response to these stimuli was calculated in seven regions of interest (ROIs) likely involved in pain processing: contralateral anterior cingulate cortex, contralateral primary somatosensory cortex, bilateral anterior insula, contralateral dorsolateral prefrontal cortex, posterior parietal cortex and contralateral premotor cortex. Results showed that participants exhibited an overall increase in spectral power during SDTP in all seven ROIs compared to both SDTnP and VT, likely reflecting the differences in the salience of these stimuli. Moreover, we observed a difference is CSD due to the type of stimulus, likely reflecting somatosensory discrimination of stimulus intensity. These results describe the different contributions of neural oscillations within these brain regions in the processing of sustained deep-tissue pain.

Healthy Pain-Free Individuals with a History of Distal Radius Fracture Demonstrate an Expanded Distribution of Experimental Referred Pain Toward the Wrist

OBJECTIVE

Nociception caused by injuries may sensitize central mechanisms causing expanded pain areas. After recovery, the status of such pain distribution and sensitivity mechanisms is unknown. The present study investigated whether individuals who have fully recovered from a distal radius fracture demonstrate increased pain sensitivity and expanded distribution of pressure-induced pain.

DESIGN

Cross-sectional single-blinded study.

SETTING

Clinical setting.

SUBJECTS

Twenty-three pain-free individuals with a history of painful distal radius fracture and 22 nonfractured, age/gender-matched controls participated in two experimental sessions (day 0, day 1) 24 hours apart.

METHODS

Pressure pain thresholds (PPTs) were recorded bilaterally at the extensor carpi radialis longus (ECRL), infraspinatus, and gastrocnemius muscles. Spatial distribution of pain was assessed following 60-second painful pressure stimulation at the ECRL (bilateral) and the infraspinatus muscles on the fractured or dominant side. Participants drew pain areas on a body map. After day 0 assessments, prolonged pain was induced by eccentric exercise of wrist extensors on the fractured/dominant side.

RESULTS

Compared with controls, pressure-induced ECRL pain in the fracture group referred more frequently toward the distal forearm (P < 0.005) on day 0. Both groups showed larger pain areas on day 1 compared with day 0 (P < 0.005), although the fracture group showed a larger relative change between days (P < 0.005). The fracture group showed larger pain areas on the fracture side compared with the contralateral side on both days (P < 0.005).

CONCLUSIONS

Prolonged pain and recovered prior painful injuries like fractures may sensitize pain mechanisms manifested as expanded pain distribution. Pressure-induced referred pain can be a simple pain biomarker for clinical use.

Effects of Nutritional Interventions in the Control of Musculoskeletal Pain: An Integrative Review

Food consumption has significant positive effects on an individual’s health status, including the reduction of symptoms associated with musculoskeletal pain. However, specific food groups indicated for the treatment of pain are not yet determined. Hence, this review aimed to analyze the effects of nutritional interventions with specific diets, oils and/or fatty acids, and foodstuffs in natura in the reduction of musculoskeletal pain. An integrative review was conducted in the following databases: Embase, PubMed, LILACS, and Google Scholar. Clinical trials written in English, Spanish, and Portuguese and published between 2000 and March 2020 were included in this review. Seventeen studies were included. Among these, a reduction of musculoskeletal pain with different types of nutritional interventions, such as vegan and Mediterranean diets and the consumption of blueberry, strawberry, passion fruit peel extract, argan oil, fish oil (omega-3), olive oil, and undenatured type II collagen and vitamin D gel capsules, was observed in 14 studies. Eight studies evaluated the profiles of several inflammatory markers, and of these, decreased interleukin (IL)-6, IL-1β, and tumor necrosis factor-α levels were observed in two studies. This review suggests that different nutritional interventions with specific diets, oils and/or fatty acids, and foodstuffs in natura reduce musculoskeletal pain, specifically in adults with osteoarthritis. Besides pain improvement, nutritional interventions, including the consumption of strawberry and vitamin D gel capsules, decrease the levels of several inflammatory markers.

Psychosocial factors, disability and quality of life in chronic shoulder pain patients with central sensitization

Chronic shoulder pain is a complex and multidimensional phenomenon with multiple causative factors involved in its perpetuation. Alteration of central nervous system processing along with the central sensitization is a predominant feature in chronic pain. Reduction in physical function has an impact on the psychological well-being of an individual. The aim of the study was to compare pain, kinesiophobia, catastrophizing, disability and quality of life in chronic shoulder pain patients with and without central sensitization. Eighty chronic unilateral shoulder pain patients in the age group of 40 to 60 years were recruited. Of them, 38 were chronic shoulder pain with central sensitization and 42 without central sensitization, classified on the basis of central sensitization inventory. Pain catastrophizing was measured using the pain catastrophizing scale, kinesiophobia using Tampa scale of kinesiophobia, disability using Shoulder pain and disability index and quality of life using 36-Item Short Form Health Survey questionnaire was evaluated in both the groups. Increased pain catastrophizing (p=0.000), kinesiophobia (p=0.000) and disability (p=0.000) was observed in centrally sensitized chronic shoulder pain patients. Also, physical component summary (p=0.000) and mental component summary (p=0.000) of SF-36 quality of life were reduced in chronic shoulder pain with central sensitization as compared to without central sensitization. Hence, these components should be included during assessment which will provide a holistic and multimodal approach towards the understanding, planning and management of chronic shoulder pain patients.

The Association of Diabetes With Knee Pain Locations, Pain While Walking, and Walking Speed: Data From the Osteoarthritis Initiative

OBJECTIVE

Osteoarthritis (OA) and diabetes mellitus (DM) often coexist and can result in negative outcomes. DM can affect pain and walking speed in people with knee OA; however, the impact of DM on OA is understudied. The purpose of this study was to investigate the association between diabetes and knee pain locations, pain severity while walking, and walking speed in people with knee OA.

METHODS

A cross-sectional analysis was used. Data from 1790 individuals from the Osteoarthritis Initiative (mean [SD] age = 69 [8.7] years) with knee pain were included and grouped into knee OA and diabetes (n = 236) or knee OA only (n = 1554). Knee pain locations were categorized as no pain, localized pain, regional pain, or diffuse pain. Knee pain during a 20-m walk test was categorized as no pain, mild, moderate, or severe knee pain. Walking speed was measured using the 20-m walk test. Multinomial and linear regression analyses were performed.

RESULTS

Diabetes was associated with regional knee pain (odds ratio [OR] = 1.77; 95% CI = 1.01-3.11). Diabetes was associated only with moderate (OR = 1.78; 95% CI = 1.02-3.10) or severe (OR = 2.52; 95% CI = 1.01-6.28) pain while walking. Diabetes was associated with decreased walking speed (B = -0.064; 95% CI = -0.09 to -0.03).

CONCLUSIONS

Diabetes was associated with regional knee pain but not with localized or diffuse knee pain and was associated with moderate to severe knee pain while walking and slower walking speed in people with knee OA.

IMPACT

Clinicians can use a knee pain map for examining knee pain locations for people with diabetes and knee OA. Knee pain during walking and walking speed should be screened for people with knee OA and diabetes because of the influence of diabetes on these parameters in this population.

LAY SUMMARY

Diabetes might be associated with specific knee pain locations, pain during activities such as walking, and reduced walking speed in people with knee OA.