Effect of exercise on pain processing and motor output in people with knee osteoarthritis: a systematic review and meta-analysis

Quadriceps motor unit properties following ACL reconstruction are associated with corticospinal excitability and motor cortex activations

Quadriceps weakness is a primary concern following anterior cruciate ligament reconstruction (ACLR), and neuroimaging studies have revealed higher motor inhibition and structural atrophy of the corticospinal tract. To investigate the contributions of supraspinal mechanisms underlying spinal motoneuron impairments and quadriceps weakness, this study explored the firing patterns of motor units (MUs) in the vastus medialis muscle following ACLR. Twenty individuals with primary ACLR and 20 matched controls performed a unilateral knee extension torque-control task at 50% of maximal voluntary effort. High-density electromyographic activity of the vastus medialis muscle was decomposed into constituent MU action potentials. Electroencephalography was used to localize cortical activity to sensory and motor brain regions. Active motor thresholds were acquired using transcranial magnetic stimulation. We compared motor unit properties, cortical activity, and corticospinal excitability between groups and limbs using mixed-effects models and Cohen's d effect sizes. Participants with ACLR had weaker quadriceps compared with contralateral and control limbs. Strength deficits were accompanied by recruitment of larger MUs with lower firing rates in the involved limb. Those with ACLR also had lower corticospinal excitability and lower contralateral hemisphere motor cortex activations during quadriceps contractions. Lower corticospinal excitability and lower activations in the sensory and motor cortices were weakly associated with smaller MU action potential amplitudes, whereas group was not. Larger, slower-firing quadriceps MUs are recruited at lower absolute and mass-normalized recruitment thresholds, but not relative recruitment thresholds after ACLR. Lower corticospinal excitability and motor cortex activity were associated with the recruitment of smaller MUs irrespective of ACLR.NEW & NOTEWORTHY Individuals with anterior cruciate ligament reconstruction (ACLR) exhibited earlier recruitment of larger MUs with lower firing rates at both absolute and mass-normalized recruitment thresholds in their involved limb when compared with contralateral and control limbs. Individuals with ACLR had lower corticospinal excitability and lower contralateral hemisphere motor cortex activations, which were weakly associated with lower firing rates as larger motor units were recruited. Reduced excitatory cortical drive may contribute to quadriceps motor unit impairments and persistent quadriceps weakness after ACLR.

Understanding Exercise-Induced Hypoalgesia: An Umbrella Review of Scientific Evidence and Qualitative Content Analysis

Background and Objectives: Exercise-induced hypoalgesia (EIH) is a topic of interest in the scientific community. This umbrella review aimed to analyze EIH research and compare it with public dissemination on X. Materials and Methods: We selected relevant EIH reviews that included a healthy population or patients with pain and studied exercise interventions. A systematic literature search was carried out in PubMed, Web of Science, SciELO, PEDro, and Google Scholar, employing the Population, Intervention, Comparison, and Outcome strategy. Data were extracted and summarized, and methodological quality was assessed with the Quality Assessment Scale for Systematic Reviews, and risk of bias with the Risk of Bias in Systematic Reviews tool. The Physical Activity Guidelines Advisor Committee was employed for evidence synthesis. Simultaneously, advanced X website searches gathered EIH-related content for analysis. Information from posts on X was qualitatively analyzed and contrasted with evidence in the literature. Results: We included nine systematic reviews and 17 narrative reviews. Systematic reviews presented high methodological quality. However, half had low risk of bias, while the other half presented high risk of bias. The EIH in healthy participants was controversial for some exercise modalities, such as aerobic exercise, and the influence of psychological variables. Modalities, such as isotonic resistance exercise, showed favorable effects on hypoalgesia. However, in patients with musculoskeletal pain, different exercise modalities did not generate EIH. X analysis unveiled a considerable representation of science-related content, although with prevalent misinterpretations of scientific evidence. Conclusions: EIH has been extensively studied, yet the certainty of evidence remains limited. While some exercise modalities demonstrate hypoalgesic effects in asymptomatic individuals, these effects remain unverified in patients with musculoskeletal pain. Moreover, the analysis of social media content highlights frequent misinterpretations of scientific evidence, particularly conflating hypoalgesia with analgesia. This underscores the need for more precise, evidence-based communication on social media platforms.

The effect of balance exercises on central sensitization in patients with knee osteoarthritis

The aim of this study was to evaluate the effectiveness of balance exercises on functional status, pain, balance, and central sensitization in patients with knee osteoarthritis (OA). Patients diagnosed with bilateral Kellgren-Lawrence grade ≥ 2 primary knee OA and associated central sensitization were included in the study. Patients were randomized into two groups. Both groups were provided with verbal and written information on knee OA. In addition, the intervention group received a supervised balance exercise program for 6 weeks, 3 days a week on alternating days. The outcome measures were the changes in the Central Sensitization Inventory (CSI), Visual Analog Scale (VAS) pain, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Berg Balance Scale, and Y Balance Test. Evaluations were performed at baseline, immediately after treatment (6th week) and at 12th week. The study included 40 patients, 20 patients in each group. At the end of the treatment period (6th week), the improvement in CSI score, WOMAC pain, WOMAC physical function, WOMAC total score, Y Balance Test scores, and VAS pain during activity was significantly greater in the intervention group than that in the control group (p < 0.001). Regarding the changes from baseline to the 12th week, the intervention group experienced greater improvement in most of the outcome measures. Yet, the change in WOMAC pain score, Berg Balance Scale score, and VAS pain at rest was similar between the study groups (p = 0.05, p = 0.257, and p = 0.385, respectively). A two-model multiple linear regression analysis revealed that the changes in VAS pain (during activity) after the treatment and at follow-up [(p = 0.004, adjusted R2: 0.346) and (p = 0.002, adjusted R2: 0.391), respectively], as well as changes in WOMAC pain from baseline to follow-up (p = 0.020, ΔR2 = 0.245) significantly affected central sensitization. However, changes in Y Balance Test and WOMAC total scores did not appear to have a significant impact on the improvement in central sensitization (p > 0.05). Balance exercises may provide improvement in central sensitization, functional status, and dynamic balance among patients with knee OA. The improvement in central sensitization depends mostly on the pain relief effect of balance exercises.

Knee Confidence, Fear of Movement, and Psychological Readiness for Sport in Individuals With Knee Conditions: A Systematic Review and Meta-analysis

OBJECTIVES: To (1) compare activity-related psychological factors between individuals with and without knee conditions, and (2) assess associations between these factors and objective measures of function in individuals with knee conditions. DESIGN: A priori registered systematic review with meta-analysis. LITERATURE SEARCH: MEDLINE-Ovid, Embase-Ovid, Scopus-Elsevier, CINAHL-EBSCO, SPORTDiscus-EBSCO, and Cochrane Library were searched to May 27, 2022. STUDY SELECTION CRITERIA: We included peer-reviewed primary data studies (observational and experimental) of human participants with and without knee conditions reporting knee confidence, fear of movement/avoidance beliefs, and/or psychological readiness to return to sport (RTS) or reporting correlations between these factors and objective measures of function in knee conditions. DATA SYNTHESIS: Where possible, data were pooled by knee conditions, otherwise performed narrative syntheses. The Downs and Black checklist assessed the methodological quality of the included studies. RESULTS: Forty studies (3546 participants with knee conditions; 616 participants without knee conditions) were included. There was very low-certainty evidence of higher fear of movement in individuals with knee osteoarthritis (standardized mean difference [SMD], 0.46; 95% confidence interval [CI]: 0.41, 0.52), but not in individuals with patellofemoral pain (SMD, 0.66; 95% CI: -7.98, 9.29) when compared with those without knee conditions. There was very low-certainty evidence of no differences in psychological readiness to RTS after anterior cruciate ligament reconstruction (SMD, -1.14; 95% CI: -2.97, 0.70) compared to no knee condition, and negligible to weak positive correlations between psychological readiness to RTS and objective measures of function. CONCLUSION: There was very low-certainty evidence of higher fear of movement in individuals with knee osteoarthritis compared to those without, and very low-certainty evidence of no correlations between these factors and objective measures of function following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther 2024;54(4):1-14. Epub 29 January 2024. doi:10.2519/jospt.2024.12070.

The effectiveness of a combined exercise and psychological treatment programme on measures of nervous system sensitisation in adults with chronic musculoskeletal pain - a systematic review and meta-analysis

BACKGROUND

Quantitative sensory testing (QST) offers information regarding underlying mechanisms contributing to chronic pain (CP) in adults with musculoskeletal disorders. This review examined the use of QST measures in adults with CP following participation in a combined exercise and psychological intervention.

METHODS

The review was conducted in accordance with the PRISMA guidelines. Five databases were searched from inception to November 2022. All study designs which evaluated the effects of a combined exercise and psychological treatment on measures of nervous system sensitivity in adults with chronic musculoskeletal pain were included.

RESULTS

A total of 13 studies met the selection criteria, 10 of which were included in a meta-analysis. Local pressure pain thresholds were the most frequently used measure (n = 12 studies). Meta-analysis revealed statistically significantly improvements in favour of the combined exercise and psychological intervention group, compared to a control group, for local pressure pain threshold measures [SMD = 0.44, 95% CI 0.08-0.81, I2 = 84%], pain intensity scores [SMD=-0.89, 95% CI -1.66- -0.13, I2 = 94%] and the Central Sensitisation Inventory [SMD=-0.69, 95% CI -1.37- -0.02, I2 = 87%]. There were no significant differences found between groups for remote pressure pain thresholds, temporal summation or conditioned pain modulation.

CONCLUSIONS

The results suggest that a combined exercise and psychological intervention may lead to greater improvements in local pressure pain threshold, pain intensity and Central Sensitisation Inventory scores when compared to a control intervention in adults with CP, however these findings must be interpreted with caution as a large degree of heterogeneity was present in these results (I2: 84-94%). Further large, longitudinal studies are required using standardised QST measurement procedures and patient reported outcome measures to explore changes in nervous system sensitisation.

TRIAL REGISTRATION

This systematic review is registered with PROSPERO, ID Number CRD42022380464.

Feasibility of pain informed movement program for people with knee osteoarthritis

Objective

To establish the feasibility of an intervention consisting of neuromuscular exercise, mind-body techniques, and pain neuroscience education (PNE), referred to as Pain Informed Movement in people with knee Osteoarthritis (KOA). This program has the potential to improve our understanding of intrinsic pain modulation and its role in the management of chronic pain.

Methods

This was a single-arm feasibility trial with a nested qualitative component. Primary outcome: complete follow-up. Inclusion criteria: age ≥40 years, KOA clinical diagnosis or meeting KOA NICE criteria, and pain intensity ≥3/10. The program consisted of 8-week in-person and at-home exercise sessions. PNE and mind-body techniques were provided as videos and integrated into the exercise sessions. Participants completed questionnaires and physical assessments including blood draws at baseline and program completion. Secondary feasibility outcomes: acceptability of the intervention, burden, rates of recruitment, compliance and adherence, and adverse events. A priori success criteria were identified. Participants were invited to an online focus group.

Results

19 participants were enrolled, with a complete follow-up rate of 74% (mean age 63.3 years (SD 10.5), 73% female), indicating modifications were necessary to proceed. All other success criteria were met. The focus groups revealed that the video content pertaining to the mind-body techniques would benefit from on screen demonstrations.

Conclusion

The Pain Informed Movement program is deemed feasible, with minor modifications needed to proceed. A pilot two-arm RCT will be conducted to establish the feasibility and explore potential effects of Pain Informed Movement compared to conventional neuromuscular exercise and standard OA education.

Lessons learnt from a nationally funded training and mentoring programme for early-mid career musculoskeletal researchers in Australia

INTRODUCTION

Quality training and mentoring are crucial components of successful career development for early mid career researchers (EMCRs). This paper describes the overarching framework of novel ongoing national Training and Mentoring Programme Melbourne University Sydney Queensland:Impact (MUSQ:Impact) for musculoskeletal researchers, including a description of how it was set up and established, and lessons learned from its implementation.

RESULTS

The MUSQ:Impact programme spans four multidisciplinary musculoskeletal research teams across three universities in Australia, comprising 40-60 EMCR members. It was established to provide EMCRs with a unique learning environment and opportunities to gain exposure to, and network with, other national musculoskeletal research teams. Specific goals are to focus on core research competencies (e.g. writing skills, managing grant budgets, public speaking and media engagement, research translation), provide career mentoring, fund development activities (e.g. conference attendance, laboratory visits, skill development courses), and share training resources (e.g. data dictionaries, project summaries). A Steering Committee of 10-12 EMCR members, co-chaired by a senior researcher and one EMCR, is responsible for overseeing MUSQ:Impact and organising regular activities, including a monthly webinar series, a mentor/mentee scheme, annual group research retreats, annual infographic competition, and funding awards. An evaluation survey found that most participants perceived each activity to be beneficial and of value to their research career and development.

CONCLUSION

This paper presents the structure of national training and mentoring programme that serves as a potential template for other research teams to adapt within their own contexts.

The Effect of Exercise on Pain in People with Cancer: A Systematic Review with Meta-analysis

INTRODUCTION

Cancer-related pain is common and undertreated. Exercise is known to have a pain-relieving effect in non-cancer pain.

OBJECTIVES

This systematic review aimed to evaluate (1) the effect of exercise on cancer-related pain in all cancers, and (2) whether the effect of exercise differed according to exercise mode, degree of supervision, intervention duration and timing (during or after cancer treatment), pain types, measurement tool and cancer type.

METHODS

Electronic searches were undertaken in six databases to identify exercise studies evaluating pain in people with cancer, published prior to 11 January 2023. All stages of screening and data extraction were conducted independently by two authors. The Cochrane risk of bias tool for randomised trials (RoB 2) was used and overall strength of evidence was assessed using the GRADE approach. Meta-analyses were performed overall and by study design, exercise intervention and pain characteristics.

RESULTS

In total, 71 studies reported in 74 papers were eligible for inclusion. The overall meta-analysis included 5877 participants and showed reductions in pain favouring exercise (standardised mean difference - 0.45; 95% confidence interval - 0.62, - 0.28). For most (> 82%) of the subgroup analyses, the direction of effect favoured exercise compared with usual care, with effect sizes ranging from small to large (median effect size - 0.35; range - 0.03 to - 1.17). The overall strength of evidence for the effect of exercise on cancer-related pain was very low.

CONCLUSION

The findings provide support that exercise participation does not worsen cancer-related pain and that it may be beneficial. Better pain categorisation and inclusion of more diverse cancer populations in future research would improve understanding of the extent of benefit and to whom.

PROSPERO REGISTRATION NUMBER

CRD42021266826.

Autonomic responses to aerobic and resistance exercise in patients with chronic musculoskeletal pain: A systematic review

BACKGROUND

It is unknown whether patients with chronic musculoskeletal pain (CMP) show autonomic dysregulation after exercise, and the interventional effects of exercise on the autonomic dysregulation have not been elucidated. The objectives of this study were to reveal acute autonomic responses after aerobic and resistance exercises and the interventional effects of both exercises on autonomic dysregulation in patients with CMP.

METHODS

A systematic search using nine electronic databases was performed based on three key search terms: "chronic musculoskeletal pain," "autonomic nervous system," and "exercise." Data were extracted from measurements of the autonomic nervous system and pain.

RESULTS

We found a total of 1170 articles; 17 were finally included, incorporating 12 observational and five interventional studies. Although a comparator has not been specified, healthy controls were compared to patients with CMP in observational studies. Three of five interventional studies were pre-post study with healthy controls as a comparator or no controls. The other two interventional studies were randomized controlled trial with a different treatment e.g., stretching. There were four good, 10 fair, and three poor-quality articles. The total number of participants was 617, of which 551 were female. There was high heterogeneity among the five disease conditions and nine outcome measures. Following one-time exposure to aerobic and resistance exercises, abnormal autonomic responses (sympathetic activation and parasympathetic withdrawal), which were absent in healthy controls, were observed in patients with CMP. The effects of aerobic and resistance exercise as long-term interventions were unclear since we identified both positive effects and no change in the autonomic activities in patients with CMP.

CONCLUSIONS

This study indicates dysfunctional autonomic responses following one-time exposure to exercise and inconsistent interventional effects in the autonomic activities in patients with CMP. Appropriate therapeutic dose is necessary for studying the management of autonomic regulation and pain after exercise.

How Do Nonsurgical Interventions Improve Pain and Physical Function in People With Osteoarthritis? A Scoping Review of Mediation Analysis Studies

OBJECTIVE

Nonsurgical interventions are recommended for osteoarthritis (OA). However, how interventions change pain and physical function is unclear. Therefore, the objectives of this scoping review were to 1) identify what potential mediators of nonsurgical interventions on pain and physical function have been evaluated and 2) summarize the findings according to intervention, joint, and outcome.

METHODS

We searched Medline, Embase, CINAHL, Cochrane Central Register of Controlled Trials, and Scopus databases. Studies were included if they conducted a mediation analysis on a randomized controlled trial evaluating a nonsurgical intervention on OA of any joint. Outcomes were pain and physical function.

RESULTS

Nine knee OA studies, evaluating diet plus exercise, exercise, unloading shoes, high-expectation communication during acupuncture, and telephone-based weight loss plus exercise were identified. Except for weight loss and self-efficacy, putative mediators (knee muscle perfusion/extensor strength/adduction moment, systemic inflammatory biomarkers, physical activity, dietary intake, and pain beliefs) were evaluated by single studies. Ten mediators partially mediated intervention (diet plus exercise, exercise, high-expectation communication) effects on pain and physical function. Eight mediators were common to pain and function (reduced weight, increased knee extensor strength, and increased self-efficacy). Constant knee flexor muscle perfusion partially mediated exercise effects on pain, and knee pain relief partially mediated exercise effects on function.

CONCLUSION

In knee OA, some evidence suggests that the benefits of 1) diet and exercise are mediated through changes in body weight, systemic inflammation, and self-efficacy; 2) exercise is mediated through changes in knee muscle strength and self-efficacy; and 3) high-expectation communication style is mediated through changes in self-efficacy.

The effects of pain science education plus exercise on pain and function in chronic Achilles tendinopathy: a blinded, placebo-controlled, explanatory, randomized trial

ABSTRACT

Exercise is the standard of care for Achilles tendinopathy (AT), but 20% to 50% of patients continue to have pain following rehabilitation. The addition of pain science education (PSE) to an exercise program may enhance clinical outcomes, yet this has not been examined in patients with AT. Furthermore, little is known about how rehabilitation for AT alters the fear of movement and central nervous system nociceptive processing. Participants with chronic AT (N = 66) were randomized to receive education about AT either from a biopsychosocial (PSE) or from a biomedical (pathoanatomical education [PAE]) perspective. Simultaneously, all participants completed an exercise program over 8 weeks. Linear mixed models indicated that there were no differences between groups in (1) movement-evoked pain with both groups achieving a clinically meaningful reduction (mean change [95% CI], PSE: -3.0 [-3.8 to -2.2], PAE = -3.6 [-4.4 to -2.8]) and (2) self-reported function, with neither group achieving a clinically meaningful improvement (Patient-Reported Outcomes Measurement Information System Physical Function-PSE: 1.8 [0.3-3.4], PAE: 2.5 [0.8-4.2]). After rehabilitation, performance-based function improved (number of heel raises: 5.2 [1.6-8.8]), central nervous system nociceptive processing remained the same (conditioned pain modulation: -11.4% [0.2 to -17.3]), and fear of movement decreased (Tampa Scale of Kinesiophobia, TSK-17: -6.5 [-4.4 to -8.6]). Linear regression models indicated that baseline levels of pain and function along with improvements in self-efficacy and knowledge gain were associated with a greater improvement in pain and function, respectively. Thus, acquiring skills for symptom self-management and the process of learning may be more important than the specific educational approach for short-term clinical outcomes in patients with AT.

Effect of functional weightbearing versus non-weightbearing quadriceps strengthening exercise on contact force in varus-malaligned medial knee osteoarthritis: A secondary analysis of a randomized controlled trial

BACKGROUND

Knee osteoarthritis progression may be related to altered knee loads, particularly in those with varus malalignment. Using randomized controlled trial data, this secondary analysis of complete datasets (n = 67) compared the effects of a functional weightbearing (WB) and non-weightbearing quadriceps strengthening exercise (NWB) program on measures of medial tibiofemoral joint contact force (MTCF) during walking.

METHODS

Participants aged ≥50 years and with medial knee osteoarthritis and varus malalignment were randomly allocated to a 12-week, home-based, physiotherapist-prescribed exercise program comprised of WB exercises (n = 31), or NWB exercise (n = 36). Three-dimensional lower-body motion, ground reaction forces, and surface electromyograms from six lower-limb muscles were acquired during walking at baseline and at 12-weeks follow-up. An electromyogram-informed neuromusculoskeletal model estimated bodyweight (BW) normalized MTCF (peak and impulse), including external and muscular contributions to MTCF.

RESULTS

There was no between-group difference in the change in peak MTCF (-0.02 [-0.12, 0.09] BW) or MTCF impulse (-0.01 [-0.06, 0.03] BW·s). There was a between-group difference in the muscle contribution to peak MTCF (-0.08 [-0.15, -0.00] BW) and MTCF impulse (-0.04 [-0.08, -0.00] BW·s), whereby the muscle contribution reduced more in the NWB group over time compared to the WB group. There was also a between group-difference in the external contribution to peak MTCF (0.09 [0.01, 0.18] BW), but this reduced more in the WB group than in the NWB group.

CONCLUSIONS

Our findings suggest no difference in MTCF between the two exercise programs, but differences in the contribution to MTCF between the two exercise programs were observed in those with medial knee osteoarthritis and varus malalignment.

Acute effects of exercise on pain symptoms, clinical inflammatory markers and inflammatory cytokines in people with rheumatoid arthritis: a systematic literature review

Background

Exercise is advocated in the treatment of rheumatoid arthritis (RA). However, uncertainty around the acute effects of exercise on pain and inflammation may be stopping people with RA from exercising more regularly.

Objectives

To determine the acute effects of exercise on pain symptoms, clinical inflammatory markers, and inflammatory cytokines in RA.

Design

A systematic review of the literature.

Data sources and methods

Five databases were searched (PubMed, Cochrane Library, CINAHL, Scopus and SPORTDiscus); inclusion criteria were studies with acute exercise, a definite diagnosis of RA and disease characteristics assessed by clinical function (i.e., disease activity score, health assessment questionnaire and self-reported pain), clinical markers associated with inflammation (i.e., c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)), and inflammatory cytokines (i.e., interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α)).

Results

From a total of 1544 articles, initial screening and full text assessment left 11 studies meeting the inclusion criteria. A total of 274 people were included in the studies (RA = 186; control = 88). Acute bouts of aerobic, resistance, and combined aerobic and resistance exercise did not appear to exacerbate pain symptoms in people with RA.

Conclusion

Post-exercise responses for pain, clinical inflammatory markers and inflammatory cytokines were not different between people with or without RA. Exercise prescription was variable between studies, which limited between-study comparisons. Therefore, future investigations in people with RA are warranted, which combine different exercise modes and intensities to examine acute effects on pain symptoms and inflammatory markers.

Registration

The PROSPERO international prospective register of systematic reviews - CRD42018091155.

Temporal Summation in Fibromyalgia Patients: Comparing Phasic and Tonic Paradigms

Introduction

Fibromyalgia (FM) is associated with dysfunctional pain modulation mechanisms, including central sensitization. Experimental pain measurements, such as temporal summation (TS), could serve as markers of central sensitization and have been previously studied in these patients, with conflicting results. Our objective in this study was to explore the relationships between two different protocols of TS (phasic and tonic) and test the associations between these measures and other clinical variables.

Materials and Methods

In this cross-sectional analysis of a randomized clinical trial, patients were instructed to determine their pain-60 test temperature, then received one train of 15 repetitive heat stimuli and rated their pain after the 1st and 15th stimuli: TSPS-phasic was calculated as the difference between those. We also administered a tonic heat test stimulus at the same temperature continuously for 30 s and asked them to rate their pain levels after 10 s and 30 s, calculating TSPS-tonic as the difference between them. We also collected baseline demographic data and behavioral questionnaires assessing pain, depression, fatigue, anxiety, sleepiness, and quality of life. We performed univariable analyses of the relationship between TSPS-phasic and TSPS-tonic, and between each of those measures and the demographic and clinical variables collected at baseline. We then built multivariable linear regression models to find predictors for TSPS-phasic and TSPS-tonic, while including potential confounders and avoiding collinearity.

Results

Fifty-two FM patients were analyzed. 28.85% developed summation during the TSPS-phasic protocol while 21.15% developed summation during the TSPS-tonic protocol. There were no variables associated TSPS phasic or tonic in the univariable analyses and both measures were not correlated. On the multivariate model for the TSPS-phasic protocol, we found a weak association with pain variables. BPI-pain subscale was associated with more temporal summation in the phasic protocol (ß = 0.38, p = 0.029), while VAS for pain was associated with less summation in the TSPS-tonic protocol (ß = −0.5, p = 0.009).

Conclusion

Our results suggest that, using heat stimuli with pain-60 temperatures, a TSPS-phasic protocol and a TSPS-tonic protocol are not correlated and could index different neural responses in FM subjects. Further studies with larger sample sizes would be needed to elucidate whether such responses could help differentiating subjects with FM into specific phenotypes.

Implementation of Online Behavior Modification Techniques in the Management of Chronic Musculoskeletal Pain: A Systematic Review and Meta-Analysis

Purpose: The main aim of this systematic review and meta-analysis (MA) was to assess the effectiveness of online behavior modification techniques (e-BMT) in the management of chronic musculoskeletal pain. Methods: We conducted a search of Medline (PubMed), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, APA PsychInfo, and Psychological and Behavioral Collections, from inception to the 30 August 2021. The main outcome measures were pain intensity, pain interference, kinesiophobia, pain catastrophizing and self-efficacy. The statistical analysis was conducted using RStudio software. To compare the outcomes reported by the studies, we calculated the standardized mean difference (SMD) over time and the corresponding 95% confidence interval (CI) for the continuous variables. Results: Regarding pain intensity (vs. usual care/waiting list), we found a statistically significant trivial effect size in favor of e-BMT (n = 5337; SMD = −0.17; 95% CI −0.26, −0.09). With regard to pain intensity (vs. in-person BMT) we found a statistically significant small effect size in favor of in-person BMT (n = 486; SMD = 0.21; 95%CI 0.15, 0.27). With respect to pain interference (vs. usual care/waiting list) a statistically significant small effect size of e-BMT was found (n = 1642; SMD = −0.24; 95%CI −0.44, −0.05). Finally, the same results were found in kinesiophobia, catastrophizing, and self-efficacy (vs. usual care/waiting list) where we found a statistically significant small effect size in favor of e-BMT. Conclusions: e-BMT seems to be an effective option for the management of patients with musculoskeletal conditions although it does not appear superior to in-person BMT in terms of improving pain intensity.

Pain descriptors and determinants of pain sensitivity in knee osteoarthritis: a community-based cross-sectional study

Objectives

To explore pain characteristics in individuals with knee osteoarthritis (KOA), to compare pain sensitivity across individuals with KOA, chronic back pain (CBP) and pain-free individuals (NP), and to examine the relationship between clinical and pain characteristics with pain sensitivity in KOA.

Methods

Cross-sectional, community-based online survey. Two datasets were combined comprising Dutch individuals of ≥ 40 years of age, experiencing chronic knee pain (KOA, N = 445), chronic back pain (CBP, N = 504), or no pain (NP, N = 256). Demographic and clinical characteristics, global health, physical activity/exercise, and pain characteristics including intensity, spreading, duration, quality (SF-MPQ), and sensitivity (PSQ) were assessed. Differences between (sub)groups were examined using analyses of variance or Chi-square tests. Regression analyses were performed to examine determinants of pain sensitivity in the KOA group.

Results

Quality of pain was most commonly described as aching, tender, and tiring-exhausting. Overall, the KOA group had higher levels of pain sensitivity compared to NP group, but lower levels than the CBP group. Univariately, pain intensity, its variability and spreading, global health, exercise, and having comorbidities were weakly related to pain sensitivity (standardized betas: 0.12-0.27). Symptom duration was not related to pain sensitivity. Older age, higher levels of continuous pain, lower levels of global health, and exercise uniquely contributed, albeit modest, to pain sensitivity (P&lt;0.05).

Conclusion

Continuous pain such as aching and tenderness in combination with decreased physical activity may be indicative for a subgroup of individuals at risk for pain sensitivity and, ultimately, poor treatment outcomes.

Evidence of Widespread Mechanical Hyperalgesia but Not Exercise-Induced Analgesia in Athletes With Mild Patellar Tendinopathy Compared With Pain-Free Matched Controls: A Blinded Exploratory Study

OBJECTIVE

The aim of the study was to assess centrally induced pain processing with pressure pain thresholds bilaterally and remotely in active volleyball and basketball athletes with mild patellar tendinopathy compared with asymptomatic control athletes. Secondary objective was to explore the role of exercise-induced analgesia during a training session in athletes with patellar tendinopathy.

DESIGN

In this exploratory study, pressure pain thresholds of 21 patellar tendinopathy athletes and 16 age- and sex-matched asymptomatic team members were measured by a blinded assessor bilaterally on the patellar tendon and unilaterally on the elbow extensor tendon with a pressure algometer before, during, and after a regular training session.

RESULTS

Patellar tendinopathy athletes had a significantly higher average body mass index compared with asymptomatic athletes (mean difference 1.75 kg/m2; 95% confidence interval = 0.35-3.15, P = 0.02). At baseline, athletes with patellar tendinopathy showed lowered pressure pain thresholds in the affected knee (P = 0.001), unaffected knee (P < 0.001), and elbow (P = 0.01) compared with controls. No clear patterns were identified to explain between-group differences in pressure pain thresholds before, during, and after exercise.

CONCLUSIONS

This exploratory study found primary and secondary mechanical hyperalgesia in athletes with patellar tendinopathy compared with asymptomatic athletes. Further research is required on the effects of an acute exercise bout on pain thresholds in this population.

Exercise and education for community-dwelling older participants with knee osteoarthritis: a video-linked programme protocol based on a randomised controlled trial

Background

Neuromuscular and quadriceps exercises have been shown to be effective approaches to relieve pain and to improve function for patients with knee osteoarthritis. In this study, we aim to provide an informative feasible model in which therapeutic exercise and education will be undertaken with physiotherapy supervision and instruction via video link. We also aim to explore the relationship between program-induced pain alleviation/functional improvements and reduction in irritability, which might be mediated through program-induced psychosocial benefits.

Methods

In this proposed two-parallel group (neuromuscular exercise versus quadriceps exercise), single-blinded, randomised controlled trial, participants aged ≥50 years with osteoarthritic knee pain will undergo a 12-week intervention, comprising video-linked education, supervised exercises, and a 12-week follow-up. Seven measurements will be taken to collect longitudinal data. A generalised estimating equation will be used to establish the adjusted difference in effectiveness on pain, function, irritability, and psychosocial outcomes between participants undertaking neuromuscular exercises and those undertaking quadriceps exercises. The primary outcomes are overall average pain in the knee joint during walking, as assessed through the 11-point Numerical Pain Rating Scale, and the Western Ontario and McMaster Universities osteoarthritis index physical function subscale. Furthermore, pressure pain threshold and changes in self-report pain scores pre-, during, and post-exercise were also measured as an indication of irritability. In addition, both the 6-min walk test and a timed up & go test were used to assess walking function performance. Finally, patients’ emotions (e.g., fear and catastrophising), self-trust, needs in terms of disease knowledge, mental resilience, social support and health-related quality of life were investigated. Two four-wave cross-lagged models will be used to investigate directional relationships, aiming to investigate the complex mechanisms concerning the effects of exercise programmes.

Discussion

Through summarising the study’s strengths and limitations, this study may provide promising insights in terms of exercise therapy optimisation for people with knee osteoarthritis and/or other chronic pain within a psychosocial framework.

Trial registration

ChiCTR2100041978 (chictr.org.cn), January 10, 2021.