People with musculoskeletal shoulder pain demonstrate no signs of altered pain processing

The impact of central sensitization-related symptoms on subacromial steroid injection outcomes in patients with subacromial impingement syndrome: an observational study

Background

Evidence indicates that central sensitization (CS) plays a role in subacromial impingement syndrome (SIS). Reduced treatment response has been associated with pretreatment pain sensitization features, such as CSrelated symptoms.

Methods

Patients who received subacromial steroid injection were evaluated before the injection, at the first and third months. CS-related symptoms were investigated through the central sensitization inventory (CSI), and pain hypersensitivity was investigated by pressure pain threshold (PPT). Patients were evaluated using the visual analog scale (VAS), Quick Disabilities of the Arm, Shoulder, and Hand, Hospital Anxiety and Depression Scale, and Short Form-36.

Results

With the injection, all participants had a significant reduction in shoulder pain (P < 0.05). In all follow-ups, VAS values did not differ significantly between the groups, and patients with CSI ≥ 40 had higher levels of disability, anxiety, depression, and worse quality of life before treatment (P < 0.05). Post-injection disability decreased significantly in the CS group and reached similar levels in both groups at the third month (P > 0.05). Although both groups' PPT values were comparable pre-treatment and at the third month, the CS group's affected shoulder showed a notable PPT decline at the first month (P < 0.05).

Conclusions

Pre-treatment CS-related symptoms had no effect on SIS patients' responsiveness to steroid injections.

Methodological Variation Among Studies Evaluating Pain Processing in Tendinopathy: A Scoping Review

Background/Objectives: Tendinopathy is a condition associated with pain and limited function. While upper and lower extremity tendinopathies may have different functional implications, there have been a number of reports supporting different patterns of dysfunction in pain processing and inhibition. The purpose of this scoping review was to examine the methods across studies examining pain processing in patients with upper and lower extremity tendinopathy. Methods: Five electronic databases (PubMed, Scopus, CINAHL, the Cochrane Library, and SPORTDiscus) and gray literature sources were searched from inception through 15 April 2024, using appropriate keywords and relevant synonyms. Results: In total, 3219 titles were retrieved from the searches, with 43 studies retained for final inclusion. Of the 43 studies, 22 were specific to upper extremity tendinopathies, 19 were specific to lower extremity tendinopathies, and 2 studies included mixed samples. Physical testing to detect nervous system sensitization was most commonly performed using pressure pain thresholds. Although infrequent, questionnaire instruments were used mostly to include the central sensitization inventory. Substantial variation was noted across studies in mode of testing and instruments used, while patient demographics and inclusion criteria were not clearly reported in many instances. Thirty-one studies (72%) reported nervous system sensitization or dysfunction in tendinopathy, while 13 (28%) did not. Conclusions: While the difference between pain processing in tendinopathy is likely multifactorial, the results of this review identified substantial variability in methodology used and reporting in tendon pain research. As inconsistency in evidence can limit clinical guidance, efforts to standardize tendinopathy pain research appear warranted.

Altered Sensory Processing in People Attending Specialist Orthopaedic Consultation for Management of Persistent Shoulder Pain: An Observational Cross-Sectional Study

OBJECTIVES: The primary objective was to compare sensory processing measures in people attending specialist orthopaedic consultation for management of persistent shoulder pain with control participants. The secondary objective was to compare the groups' sociodemographic, clinical, general health and lifestyle, and psychological characteristics. DESIGN: Observational cross-sectional. METHODS: Participants with shoulder pain for ≥3 months, who attended a public hospital orthopaedic department (n = 119), and community participants without shoulder pain (n = 44) underwent a standardized quantitative sensory testing protocol, measuring pressure pain threshold, temporal summation, and conditioned pain modulation. Sociodemographic, clinical, general health and lifestyle, and psychological characteristics were also collected. RESULTS: Participants with shoulder pain had significantly lower pressure pain thresholds at all sites (ie, local and widespread mechanical hyperalgesia) and significantly decreased conditioned pain modulation effect (ie, descending inhibition of nociception) than control participants. There was no significant difference between groups for temporal summation. Participants with shoulder pain had decreased general health and function, less healthy lifestyles, and poorer psychological health compared with controls. CONCLUSION: People referred to specialist orthopaedic care for management of persistent shoulder pain had clinical signs of altered sensory processing and poor health outcomes. J Orthop Sports Phys Ther 2024;54(10):1-10. Epub 25 July 2024. doi:10.2519/jospt.2024.12512.

Reliability of Pressure Pain Threshold (PPT) and Conditioned Pain Modulation (CPM) in Participants with and without Chronic Shoulder Pain

The objectives of this study were to estimate the intra-rater and inter-rater reliability of the Pressure Pain Threshold (PPT) and Conditioned Pain Modulation (CPM) in healthy participants and patients with chronic shoulder pain. Additionally, the Standard Error of Measurement (SEM) and Smallest Detectable Change (SDC) were calculated. Thirty-one healthy volunteers and twenty patients with chronic shoulder pain were assessed using the PPT and CPM by two raters, with a 24 h interval between sessions. Excellent intra-rater reliability was demonstrated for PPT, with similar SEM and SDC when assessed by the same rater. The inter-rater reliability for PPTs in patients was moderate to good (ICC = 0.59-0.89) with higher SEM (73.83-121.98 kPa) and SDC (61.58-97.59) values than the asymptomatic group (ICC = 0.92-0.96, SEM = 49.61-103.12 kPa, SDC = 42.01-56.30) respectively. CPM's intra-rater reliability was good (ICC = 0.82) in the patients and moderate (ICC = 0.67) in the asymptomatic group, while inter-rater reliability was low for the asymptomatic group (ICC = 0.37) and extremely low (ICC = 0.074) for the patients, with comparable SEM and SDC outcomes in both groups. PPT and CPM measurements are highly reliable when conducted by the same rater on the same day. Patients had lower inter-rater PPT reliability but better intra-rater CPM reliability. Clinicians need to be mindful of potential variability when interpreting these test results.

Evaluation of the segmental distribution of pain sensitivity among patients with central sensitization associated with chronic subacromial pain syndrome: A cross-sectional study

INTRODUCTION

Pain sensitivity is the main finding of central sensitization (CS) and can occur in patients with chronic shoulder pain. However, there is limited evidence concerning the distribution of pain sensitivity in shoulders, forearms, and legs in patients with CS associated with chronic shoulder pain. The present study aimed to determine the distribution of pain sensitivity in patients with CS associated with chronic subacromial pain syndrome (SPS).

METHOD

This cross-sectional study included 58 patients with chronic SPS and CS (patient group) and 58 healthy participants (control group). The presence of CS was determined using the Central Sensitization Inventory (CSI). To determine the distribution of pain sensitivity, pressure pain threshold (PPT) measurements were performed from the shoulders, forearms, and legs.

RESULTS

There was no significant difference between the two groups in terms of sociodemographic data (p > 0.05). The patient group had a significantly higher CSI score (p < 0.001) and lower PPTs in all regions (p < 0.05) than the control group. Unlike the control group, the patient group had lower PPTs on the affected side for the shoulder [mean difference (MD) 95% confidence interval (CI): 1.2 (-1.7 to -0.6)], forearm [MD 95% CI: 1.1 (-1.7 to -0.6)], and leg [MD 95% CI: 0.9 (-1.4 to -0.3)] compared with the contralateral side (p < 0.001).

CONCLUSION

Pain sensitivity is more pronounced in the affected shoulder and the forearm and leg located on this side than in those on the contralateral side in patients with CS associated with chronic SPS.

Are clinical outcomes associated with baseline sensory profiles in people with musculoskeletal shoulder pain? Protocol for a prospective longitudinal observational study

BACKGROUND

Musculoskeletal shoulder pain is a common problem and its symptoms often become persistent. The experience of pain is multidimensional, and therefore, a range of patient characteristics may influence treatment response. An altered sensory processing has been associated with persistent musculoskeletal pain states and may contribute to outcomes in patients with musculoskeletal shoulder pain. The presence and potential impact of altered sensory processing in this patient cohort is not currently known. The aim of this prospective longitudinal cohort study is to investigate if baseline sensory characteristics are associated with clinical outcomes in patients presenting to a tertiary hospital with persistent musculoskeletal shoulder pain. If found, a relationship between sensory characteristics and outcome may lead to the creation of more effective treatment strategies and improvements in risk adjustment and prognosis.

METHODS

This is a single-centre prospective cohort study with 6-, 12- and 24-month follow-up. A total of 120 participants aged ≥18 years with persistent musculoskeletal shoulder pain (≥3 months) will be recruited from an Australian public tertiary hospital orthopaedic department. Baseline assessments, including quantitative sensory tests and a standardised physical examination, will be performed. In addition, information will be obtained from patient interviews, self-report questionnaires and medical records. Follow-up outcome measures will comprise information from the Shoulder Pain and Disability Index and a six-point Global Rating of Change scale.

ANALYSIS

Descriptive statistics will be used to report baseline characteristics and outcome measures over time. Change in outcome measures at the primary endpoint of six months from baseline will be calculated using paired t-tests. Associations between baseline characteristics and outcomes at a 6-month follow-up will be reported using multivariable linear and logistic regression models.

DISCUSSION

Understanding the relationship between sensory profile and the variable response to treatment in people with persistent musculoskeletal shoulder pain may enhance our understanding of the mechanisms contributing to the presentation. In addition, through better understanding of the contributing factors, the results of this study may contribute to the development of an individualised, patient-centred approach to treatment for people with this highly prevalent and debilitating condition.

Sensitivity to movement-evoked pain, central sensitivity symptoms, and pro-nociceptive profiles in people with chronic shoulder pain: A parallel-group cross-sectional investigation

OBJECTIVE

To investigate whether sensitivity to movement-evoked pain (SMEP), central sensitivity symptom burden, and quantitative sensory testing (QST) outcomes differ between healthy controls and people with chronic shoulder pain.

METHODS

People with chronic shoulder pain (n = 39) and healthy controls (n = 26) completed validated questionnaires measuring demographic, pain characteristics, psychological factors, social support, sleep quality, central sensitivity inventory (CSI), and physical activity levels. A blinded assessor administered QST measuring pressure pain threshold, temporal summation, conditioned pain modulation, and cold hyperalgesia. All participants performed repeated lifting of weighted canisters and reported severity of pain over successive lifts of the weighted canisters. Between-group differences in the QST, SMEP and CSI scores were investigated. Demographic and psychosocial variables were adjusted in the analyses.

RESULTS

Dynamic mechanical allodynia, mechanical temporal summation, movement-evoked pain scores, SMEP index, and CSI scores were significantly (p ≤ 0.05) higher in the chronic shoulder pain group than in healthy controls. A significant proportion of people with chronic shoulder pain presented with pro-nociceptive profiles and experienced higher pain severity, interference, and disability.

CONCLUSIONS

People with chronic shoulder pain displayed symptoms and signs of central sensitization. Future research should investigate the predictive role of central sensitization on clinical outcomes in shoulder pain.

Relationship between Pain Intensity, Physical Factors, Pronociceptive Pain Modulation Profile and Psychological Vulnerability on Upper Limb Disability in Older Patients with Chronic Shoulder Pain

BACKGROUND

Chronic shoulder pain is a very prevalent condition causing disability and functional impairment. The purpose of the study was to evaluate the relationship between pain intensity, physical variables, psychological vulnerability, pronociceptive pain modulation profile and disability in older people with chronic shoulder pain.

METHODS

A cross-sectional study was carried out. A total of 56 participants with non-specific chronic shoulder pain of the "Complejo Hospitalario Universitario" (Granada) and 56 healthy controls were included. The outcomes evaluated were pain intensity (visual analogue scale), physical factors (dynamometry for grip strength), psychological vulnerability (Fear-Avoidance Beliefs Questionnaire and Tampa Scale of Kinesiophobia), pronociceptive pain modulation profile (pain pressure algometry) and disability (Quick Disability Arm Shoulder Hand questionnaire).

RESULTS

Disability showed a positive correlation with pain and psychological vulnerability (p < 0.05) and a negative correlation with pronociceptive pain variables and dynamometry (p < 0.001). Psychological vulnerability also presented a strong negative correlation with proprioceptive pain variables and dynamometry and a positive correlation with pain (p < 0.05). In regard to the pronociceptive pain modulation profile, a strong negative correlation with pain (p < 0.001) and a positive moderate correlation with dynamometry (p < 0.001) were shown.

CONCLUSIONS

Our results support a strong association between disability, psychological vulnerability and pronociceptive pain modulation profile in older adults with chronic shoulder pain.

Investigating the effects of mobilization with movement and exercise on pain modulation processes in shoulder pain - a single cohort pilot study with short-term follow up

OBJECTIVE

To explore the association between manual therapy and exercise and pain modulation and clinical characteristics in people with musculoskeletal shoulder pain.

METHODS

This is a prospective, longitudinal, single cohort pilot study. People with shoulder pain for longer than 6 weeks underwent 4 weeks of glenohumeral mobilization with movement and shoulder exercises. Measures of pain modulation, shoulder pain, disability, range of motion and psychosocial factors were assessed at baseline and immediately after the 4-week period of treatment. Treatment effectiveness was assessed through parametric, non-parametric and multilevel modeling statistics.

RESULTS

Twenty-three individuals participatedwith no loss to follow-up. Significant and meaningful improvements in shoulder pain (NRS mean change 1.6/10, 95% CI 0.4 to 2.7), disability (SPADI mean change 20.5/100, 95% CI 13.1 to 27.9) and range of motion (mean change 33°, 95% CI 23 to 43°) were observed following treatment. Statistical but non-clinically meaningful changes were observed in temporal summation of pain (mean change 0.3/10, 95% CI 0.1 to 0.4) and anxiety (mean change 0.86/21, 95% CI 0.18 to 1.55). Significant reductions were observed in temporal summation of pain (mean change 0.3/10, 95% CI 0.1 to 0.4) and anxiety (mean change 0.86/21, 95% CI 0.18 to 1.55), however these were not considered clinically important. No association was found between clinical characteristics and sensory measures. No association was found between clinical characteristics and sensory measures.

CONCLUSION

Glenohumeral mobilization with movement and exercise did not improve pain modulation, despite improvements in pain, function and range of motion, in people with shoulder pain.

Mechanical Hyperalgesia but Not Forward Shoulder Posture Is Associated with Shoulder Pain in Volleyball Players: A Cross-Sectional Study

Shoulder antepulsion, altered scapular kinematics and imbalance of muscle activity are commonly associated with shoulder pain. This study aimed to observe if there is an association between the forward shoulder angle (FSA) and the pectoralis minor length index (PMI) in volleyball players with and without shoulder pain. Furthermore, this study observed if there is an association between shoulder posture and upper limb mechanical hyperalgesia in volleyball players with and without shoulder pain. Methods: a cross-sectional study was conducted in the Physiotherapy and Pain Research Center in Alcalá de Henares (Spain). A total of 56 volleyball players met the inclusion criteria and agreed to enter the study. Subjects were divided into two groups: shoulder pain group (SPG) and control group (without pain). The following measurements of the dominant sides of the players were collected: FSA, PMI, and pressure pain threshold (PPT) in serratus anterior, lower trapezius, infraspinatus, teres minor, upper trapezius, levator scapulae, pectoralis major, radial nerve, cubital nerve, and median nerve. Results: The Spearman’s Rho revealed no significant correlations were found between FSA and PMI. Moreover, Spearman’s Rho test revealed in the SPG a negative moderate correlation between FSA and Infraspinatus-PPT (Rho = −0.43; p = 0.02); FSA and levator scapulae-PPT (Rho = −0.55; p < 0.01); FSA and pectoralis major-PPT (Rho = −0.41; p = 0.02); PMI and cubital nerve-PPT (Rho = −0.44; p = 0.01). Conclusions: No association was found between the forward shoulder angle and the pectoralis minor index in volleyball players with and without shoulder pain. There is a moderate negative association between shoulder forward angle and muscle mechanical hyperalgesia in volleyball players with shoulder pain, but no such associations were found in volleyball players without shoulder pain. Treatment of the infraspinatus, levator scapulae, pectoralis major, and pectoralis minor muscles could improve shoulder pain and ulnar nerve mechanosensitivity.

A Central Nervous System Focused Treatment Program for People with Frozen Shoulder: A Feasibility Study

Background: Frozen shoulder (FS) is a highly disabling pathology of poorly understood etiology, which is characterized by the presence of intense pain and progressive loss of range of motion (ROM). The aim of this study is to evaluate the feasibility and clinical impact of a CNS-focused treatment program for people with FS. Methods: 10 subjects with primary FS received a 10-week CNS-focused intervention including sensory discrimination training and graded motor imagery techniques delivered as clinic sessions (60 min) and home therapy (30 min five times per week). Measurements were taken at baseline, after a 2-week “washout” period, after treatment, and at three months follow-up. The Shoulder Pain and Disability Index (SPADI) was the primary outcome. Secondary measures were feasibility-related outcomes, self-reported shoulder pain, active and passive range of motion, two-point discrimination threshold (TPDT), left/right judgement task (LRJT), fear-avoidance (Tampa Scale for Kinesiophobia), pain catastrophization (Pain Catastrophizing Scale), and pain sensitization (Central Sensitization Inventory). A Student’s t-test was used to assess the “washout” period. A repeated measure analysis of variance (ANOVA) was used to evaluate within-subjects’ differences for all outcome measures in the different assessment periods and a pairwise analysis was used to compare between the different assessment points. Statistical significance was set at p < 0.05. Results: 70% of participants completed the treatment. No significant changes were found after “washout” period except for TPDT (p = 0.02) and SPADI (p = 0.025). Improvements in self-reported shoulder pain (p = 0.028) and active shoulder flexion (p = 0.016) were shown after treatment (p = 0.028) and follow-up (p = 0.001) and in SPADI at follow-up (p = 0.008). No significant changes were observed in TPDT, LRJT, fear-avoidance, pain catastrophization, and pain sensitization. Conclusions: a CNS-focused treatment program might be a suitable approach to improve pain and disability in FS, but further research is needed to draw firm conclusions.

Conditioned Pain Modulation Is Not Impaired in Individuals with Frozen Shoulder: A Case-Control Study

Frozen shoulder (FS) is a poorly understood condition resulting in substantial shoulder pain and mobility deficits. The mechanisms behind FS are not yet fully understood, but, similar to other persistent pain states, central pain mechanisms may contribute to ongoing symptoms in this population. The objective of this research was to investigate conditioned pain modulation (CPM) in people with FS compared with pain-free individuals. A total of 64 individuals with FS and 64 healthy volunteers participated in this cross-sectional study. CPM was assessed by using the pressure pain threshold (PPT) and an occlusion cuff (tourniquet test) as the test and conditioning stimulus, respectively. The absolute and percentage of change in PPT (CPM effect) as well as pain profiles (pro-nociceptive vs. anti-nociceptive) of individuals with FS and healthy controls were calculated. No significant differences in the absolute change in the PPT or CPM effect were found in people with FS compared to pain-free controls. Moreover, no between-group differences in the percentage of subjects with pro-nociceptive and anti-nociceptive pain profiles were observed. These results suggest that endogenous pain inhibition is normally functioning in people with FS. Altered central pain-processing mechanisms may thus not be a characteristic of this population.

Pain-related fear phenotypes are associated with function of the upper limbs in individuals with shoulder pain

OBJECTIVE

To identify and describe phenotypes related to kinesiophobia, fear-avoidance, and pain catastrophizing, and determine clinical and demographic characteristics related to each phenotype as a function of self-reported function of the upper limbs in individuals with shoulder pain.

METHODS

One hundred and seventy-seven individuals with shoulder pain participated in this study. Tampa Scale of Kinesiophobia, Fear-Avoidance Beliefs Questionnaire, Pain Catastrophizing Scale, Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH), Numerical Pain of Rating Scale, and the angular onset of pain during the elevation of the arm were measured in all participants. A cluster analysis was performed considering kinesiophobia, fear-avoidance, and pain catastrophizing, then clinical and demographic characteristics of clusters were used to model individual's chance to belong to one of the clusters as a function of DASH.

RESULTS

Two clusters were identified based on kinesiophobia, fear-avoidance, and pain catastrophizing. The cluster with worse pain-related fear profile presented (p < 0.05) higher age, worse function, and higher pain intensity. This same cluster was also associated with involvement of the dominant side (OR = 2.10, 95% CI = 1.03, 4.41) and worse function (OR = 0.96, 95% CI = 0.94, 0.98).

CONCLUSION

This study identified that individuals with worse pain-related fear profile were older, with worse function, and higher pain intensity. Worse function and involvement of the dominant side were associated with the phenotype with a worse pain-related fear condition.

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.

Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

ABSTRACT

Mechanism-based classification of pain has been advocated widely to aid tailoring of interventions for individuals experiencing persistent musculoskeletal pain. Three pain mechanism categories (PMCs) are defined by the International Association for the Study of Pain: nociceptive, neuropathic, and nociplastic pain. Discrimination between them remains challenging. This study aimed to build on a framework developed to converge the diverse literature of PMCs to systematically review methods purported to discriminate between them; synthesise and thematically analyse these methods to identify the convergence and divergence of opinion; and report validation, psychometric properties, and strengths/weaknesses of these methods. The search strategy identified articles discussing methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system. Studies that assessed the validity of methods to discriminate between categories were assessed for quality. Extraction and thematic analysis were undertaken on 184 articles. Data synthesis identified 200 methods in 5 themes: clinical examination, quantitative sensory testing, imaging, diagnostic and laboratory testing, and pain-type questionnaires. Few methods have been validated for discrimination between PMCs. There was general convergence but some disagreement regarding findings that discriminate between PMCs. A combination of features and methods, rather than a single method, was generally recommended to discriminate between PMCs. Two major limitations were identified: an overlap of findings of methods between categories due to mixed presentations and many methods considered discrimination between 2 PMCs but not others. The results of this review provide a foundation to refine methods to differentiate mechanisms for musculoskeletal pain.

Sensory, Motor, and Psychosocial Characteristics of Individuals With Chronic Neck Pain: A Case-Control Study

OBJECTIVE

Given the complex and unclear etiology of neck pain, it is important to understand the differences in central sensitization as well as psychosocial factors in individuals with chronic neck pain and healthy controls. The purpose of this study was to benchmark differences in central sensitization, psychosocial factors, and range of motion between people with nonspecific chronic neck pain and healthy controls and to analyze the correlation between pain intensity, neck disability, and psychosocial factors in people with chronic neck pain.

METHODS

Thirty individuals with chronic neck pain and 30 healthy controls were included in this case-control study. Outcome measures were as follows: central sensitization (pressure pain threshold, temporal summation, and conditioned pain modulation), psychosocial factors (depressive symptoms, pain catastrophizing, and quality of life), and active cervical range of motion.

RESULTS

People with neck pain had lower local pressure pain threshold, a decrease in conditioned pain modulation, more depressive symptoms, greater pain catastrophizing, lower quality of life, and reduced range of motion for neck rotation when compared with healthy controls. In people with neck pain, moderate correlations were observed between pain intensity and quality of life (ρ = -0.479), disability and pain catastrophizing (ρ = 0.379), and disability and quality of life (ρ = -0.456).

CONCLUSIONS

People with neck pain have local hyperalgesia, impaired conditioning pain modulation, depressive symptoms, pain catastrophizing, low quality of life, and reduced active range of motion during neck rotation, which should be taken into account during assessment and treatment.

IMPACT

This study shows that important outcomes, such as central sensitization and psychosocial factors, should be considered during assessment and treatment of individuals with nonspecific chronic neck pain. In addition, pain intensity and neck disability are correlated with psychosocial factors.

Biopsychosocial Aspects in Individuals with Acute and Chronic Rotator Cuff Related Shoulder Pain: Classification Based on a Decision Tree Analysis

Biopsychosocial aspects seem to influence the clinical condition of rotator cuff related shoulder pain (RCRSP). However, traditional bivariate and linear analyses may not be sufficiently robust to capture the complex relationships among these aspects. This study determined which biopsychosocial aspects would better classify individuals with acute and chronic RCRSP and described how these aspects interact to create biopsychosocial phenotypes in individuals with acute and chronic RCRSP. Individuals with acute (<six months of pain, n = 15) and chronic (≥six months of pain, n = 38) RCRSP were included. Sociodemographic data, biological data related to general clinical health status, to shoulder clinical condition and to sensory function, and psychosocial data were collected. Outcomes were compared between groups and a decision tree was used to classify the individuals with acute and chronic RCRSP into different phenotypes hierarchically organized in nodes. Only conditioned pain modulation was different between the groups. However, the tree combined six biopsychosocial aspects to identify seven distinct phenotypes in individuals with RCRSP: three phenotypes of individuals with acute, and four with chronic RCRSP. While the majority of the individuals with chronic RCRSP have no other previous painful complaint besides the shoulder pain and low efficiency of endogenous pain modulation with no signs of biomechanical related pain, individuals with acute RCRSP are more likely to have preserved endogenous pain modulation and unilateral pain with signs of kinesiophobia.

Sedentary behaviour facilitates conditioned pain modulation in middle-aged and older adults with persistent musculoskeletal pain: a cross-sectional investigation

INTRODUCTION

Higher physical activity (PA) and lower sedentary behaviour (SB) levels have demonstrated beneficial effects on temporal summation (TS) and conditioned pain modulation (CPM) in healthy adults. This cross-sectional study investigated the relationships between PA and SB and TS/CPM responses in individuals with chronic musculoskeletal pain.

METHODS

Sixty-seven middle-aged and older adults with chronic musculoskeletal pain were recruited from the community. Questionnaires measuring demographics, pain, and psychological measures were completed. Physical activity/SB levels were measured using the International Physical Activity Questionnaire-short form and Sedentary Behaviour Questionnaire, respectively. Semmes monofilament was used to assess mechanical TS (MTS) at the most symptomatic (MTS-S) and a reference region (MTS-R); change in the pain scores (baseline-10th application) was used for analysis. Conditioned pain modulation procedure involved suprathreshold pressure pain threshold (PPT-pain4) administered before and after (CPM30sec, CPM60sec, and CPM90sec) conditioning stimulus (2 minutes; ∼12°C cold bath immersion). For analysis, PPT-pain4 (%) change scores were used.

RESULTS

PPT-pain4 (%) change scores at CPM30sec and CPM60sec demonstrated significant weak positive correlations with SB levels and weak negative correlations with PA measures. After adjusting for confounding variables, a significant positive association was found between SB (h/d) and PPT-pain4 (%) change scores at CPM30sec and CPM60sec. No significant associations between MTS and PA/SB measures.

CONCLUSION

Sedentariness is associated with higher pain inhibitory capacity in people with chronic musculoskeletal pain. The observed relationship may be characteristic of a protective (sedentary) behaviour to enhance pain modulatory mechanism. Prospective longitudinal studies using objective PA/SB measures are required to validate the observed relationship in a larger sample size.