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Shoulder pain is a highly prevalent musculoskeletal condition that frequently leads to suboptimal clinical outcomes. This study tested the extent to which circulating inflammatory biomarkers are associated with reports of shoulder pain and upper-extremity disability for a high-risk genetic by psychological subgroup (catechol-O-methyltransferase [COMT] variation by pain catastrophizing [PCS]). Pain-free adults meeting high-risk COMT × PCS subgroup criteria completed an exercise-induced muscle injury protocol. Thirteen biomarkers were collected and analyzed from plasma 48 hours after muscle injury. Shoulder pain intensity and disability (Quick-DASH) were reported at 48 and 96 hours to calculate change scores. Using an extreme sampling technique, 88 participants were included in this analysis. After controlling for age, sex, and BMI, there were moderate positive associations between higher c-reactive protein (CRP; βˆ = .62; 95% confidence interval [CI] = -.03, 1.26), interleukin-6 (IL-6; βˆ = 3.13; CI = -.11, 6.38), and interleukin-10 (IL-10; βˆ = 2.51; CI = -.30, 5.32); and greater pain reduction from 48 to 96 hours post exercise muscle injury. Using an exploratory multivariable model to predict pain changes from 48 to 96 hours, we found participants with higher IL-10 were less likely to experience a high increase in pain (βˆ = -10.77; CI = -21.25, -2.69). Study findings suggest CRP, IL-6, and IL-10 are related to shoulder pain change for a preclinical high-risk COMT × PCS subgroup. Future studies will translate to clinical shoulder pain and decipher the complex and seemingly pleiotropic interplay between inflammatory biomarkers and shoulder pain change. PERSPECTIVE: In a preclinical high-risk COMT × PCS subgroup, 3 circulating inflammatory biomarkers (CRP, IL-6, and IL-10) were moderately associated with pain improvement following exercise-induced muscle injury., (Copyright © 2023 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Abstract: Prior cohort studies validated that a subgroup defined by a specific COMT genotype and pain catastrophizing is at increased risk for heightened responses to exercise-induced or surgically induced shoulder pain. In this clinical trial, we used our preclinical model of exercise-induced muscle injury and pain to test the efficacy of interventions matched to characteristics of this high-risk subgroup (ie, personalized medicine approach). Potential participants provided informed consent to be screened for eligibility based on subgroup membership and then, as appropriate, were enrolled into the trial. Participants (n = 261) were randomized to 1 of 4 intervention groups comprised of pharmaceutical (propranolol or placebo) and informational (general education or psychologic intervention) combinations. After muscle injury was induced, participants received randomly assigned treatment and were followed for the primary outcome of shoulder pain intensity recovery over 4 consecutive days. Recovery rates were 56.4% (placebo and psychologic intervention), 55.4% (placebo and general education), 62.9% (propranolol and psychologic intervention), and 56.1% (propranolol and general education). No statistical differences were found between intervention groups in the primary analyses. Additional analyses found no differences between these intervention groups when shoulder pain duration was an outcome, and no differential treatment responses were detected based on sex, race, or level of pain catastrophizing. This trial indicates that these treatments were not efficacious for this high-risk subgroup when shoulder pain was induced by exercise-induced muscle injury. Accordingly, this phenotype should only be used for prognostic purposes until additional trials are completed in clinical populations., (Copyright © 2022 International Association for the Study of Pain.)

Background: Despite similar outcomes for surgery and conservative care, the number of surgeries to treat rotator cuff related shoulder pain has increased. Interventions designed to enhance treatment expectations for conservative care have been shown to improve patient expectations, but no studies have yet explored whether such interventions influence patient decisions to pursue surgery. The purpose of this randomized clinical trial is to examine the effect of an intervention designed to improve expectations of conservative care on the decision to have surgery., Methods: We will test the effectiveness of the Patient Engagement, Education, and Restructuring of Cognitions (PEERC) intervention which is intended to change expectations regarding conservative care. The PEERC intervention will be evaluated in a randomized, pragmatic "add-on" trial, to better understand the effect the intervention has on outcomes. Ninety-four (94) participants with rotator cuff related shoulder pain referred for physical therapy will be randomized to receive either impairment-based care or impairment-based care plus PEERC. Both groups will receive impairment-based conservative treatment created by compiling the evidence associated with established, effective interventions. Participants assigned to the impairment-based care plus PEERC condition will also receive the PEERC intervention. This intervention, informed by principles of cognitive behavioral therapy, involves three components: (1) strategies to enhance engagement, (2) education and (3) cognitive restructuring and behavioral activation. Outcomes will be assessed at multiple points between enrolment and six months after discharge. The primary outcome is patient reported decision to have surgery and the secondary outcomes are pain, function, expectations and satisfaction with conservative care., Discussion: Rotator cuff related shoulder pain is highly prevalent, and because conservative and surgical treatments have similar outcomes, an intervention that changes expectations about conservative care could alter patient reports of their decision to have surgery and ultimately could lead to lower healthcare costs and decreased risk of surgical complications., Trial Registration: This study is registered as NCT03353272 at ClincialTrials.gov., (© 2021. The Author(s).)

Our prior studies identified a high-risk phenotype (ie, high pain sensitivity variant of the catechol-O-methyltransferase gene (Single Nucleotide Polymorphism [SNP] rs6269) and pain catastrophizing scores) for shoulder pain. The current study identified sensory and psychological predictors of heightened pain responses following exercise-induced shoulder injury. Healthy participants (N = 131) with the SNP rs6269 catechol-O-methyltransferase gene and Pain Catastrophizing Scale scores ≥5 underwent baseline sensory and psychological testing followed by an established shoulder fatigue protocol, to induce muscle injury. Movement-evoked pain, pain intensity, disability, and strength were assessed 24 hours postinjury. Demographic, sensory, and psychological variables were included as predictors in full and parsimonious models for each outcome. The highest variance explained was for the shoulder disability outcome (full model R 2  = .20, parsimonious R 2  = .13). In parsimonious models, the individual predictors identified were: 1) 1st pulse heat pain sensitivity for isometric shoulder movement-evoked pain and pain intensity; 2) pressure pain threshold for shoulder disability; 3) fear of pain for active shoulder movement-evoked pain and shoulder disability; and 4) depressive symptoms for shoulder strength. Findings indicate specific pain sensitivity and psychological measures may have additional prognostic value for self-reported disability within a high-risk phenotype. These findings should be tested in a clinical cohort for validation. PERSPECTIVE: The current study extends previous work by providing insight regarding how poor shoulder outcomes may develop within a high-risk phenotype. Specifically, 1st pulse heat pain sensitivity and pressure pain threshold were sensory measures, and fear of pain and depressive symptoms were psychological measures, that improved prediction of different shoulder outcomes., (Copyright © 2021 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Shoulder surgery is a primary intervention for shoulder pain, yet many individuals experience persistent postoperative pain. Previously, we found individuals categorized as having a high-risk phenotype (comprised of COMT variation and pain catastrophizing) had approximately double the chance of not reaching a 12-month pain recovery criterion. As a means to better understand the development of persistent postoperative shoulder pain, this study advanced our previous work by examining temporal ordering of postoperative shoulder recovery based on potential mediating factors, and expansion of outcomes to include movement-evoked pain and shoulder active range of motion. Before surgery, individuals were categorized as either high-risk (high pain catastrophizing, COMT-genotype linked to low enzyme activity [n = 41]) or low-risk (low pain catastrophizing, COMT-genotype linked to normal enzyme activity [n = 107]). We then compared potential mediating variables at 3, 6, and 12 months postoperatively 1) endogenous pain modulation defined by a conditioned pain modulation paradigm; and 2) and emotion factors such as anxiety, fear of movement, and depressive symptoms. At 3 months, the high-risk subgroup had higher fear and movement-evoked pain, and causal mediation analysis confirmed the direct effect of risk subgroup on 12-month movement evoked pain. However, baseline to 12-month change in depressive symptoms were found to mediate 53% of the total effect of risk subgroup on 12-month movement-evoked pain. This study introduces potential temporal components and relationships to the development of persistent postoperative shoulder pain, which future studies will confirm and assess for potential therapeutic targets. PERSPECTIVE: This study expands upon postoperative shoulder recovery measures to include movement-evoked pain and depressive symptoms, and provides preliminary indication of temporal ordering to postoperative shoulder recovery for a preidentified high-risk subgroup. Future studies will distinguish temporal components of shoulder surgery that may optimize treatment targets of postoperative recovery., (Copyright © 2019 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Background: The Central Sensitization Inventory (CSI) and Pain Sensitivity Questionnaire (PSQ) are alternatives to quantitative sensory testing (QST) for inferring central sensitization., Objective: Explore 1) comparative validity of the CSI and PSQ with QST (construct validity) and pain-related psychological questionnaires (concurrent validity), and 2) associations with widespread pain sensitivity., Methods: Seventy-eight participants with unilateral shoulder pain less than 6 months (mean ± SD age = 39.0 ± 14.5 years, N (%) females = 36 (46.2%)) completed the CSI, PSQ, psychological questionnaires, and underwent QST for local and remote pressure pain thresholds (PPT), heat pain threshold, and suprathreshold heat pain ratings. Data from 25 age and sex-matched healthy participants (mean ± SD age = 35.2 ± 11.1 year, N (%) females = 13 (52.0%)) were used to determine a composite index for widespread pressure pain sensitivity in the shoulder pain group. Analyses included correlations between measures and between-group comparisons., Results: Only the PSQ was associated with remote PPT (rho range = -0.25 to -0.27). Both the CSI and PSQ were associated with resilience (rho range = -0.29 to -0.39), anxiety (rho range = 0.25 to 0.66), and negative affect (rho range = 0.27 to 0.67). Neither the CSI nor PSQ were associated with widespread pain sensitivity (p > 0.05). Resilience (adjusted OR = 0.41, 95% CI = 0.18; 0.94) was a distinctive feature for widespread pain sensitivity., Conclusions: These preliminary findings challenge the exclusive use of the CSI or PSQ for inferring central sensitization among individuals with shoulder pain., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Chronic musculoskeletal pain conditions are a prevalent and disabling problem. Preventing chronic musculoskeletal pain requires multifactorial treatment approaches that address its complex etiology. Prior cohort studies identified a high risk subgroup comprised of variation in COMT genotype and pain catastrophizing. This subgroup had increased chance of heightened pain responses (in a pre-clinical model) and higher 12month post-operatives pain intensity ratings (in a clinical model). This pre-clinical trial will test mechanisms and efficacy of personalized pain interventions matched to the genetic and psychological characteristics of the high-risk subgroup., Methods: Potential participants will be screened for high risk subgroup membership, appropriateness for exercise-induced muscle injury protocol, and appropriateness for propranolol administration. Eligible participants that consent to the study will then be randomized into one of four treatment groups; 1) personalized pharmaceutical and psychological education; 2) personalized pharmaceutical and general education; 3) placebo pharmaceutical and psychological education; 4) placebo pharmaceutical and psychological education. Over the 5-day study period participants will complete an exercise-induced muscle injury protocol and receive study interventions. Pain and disability assessments will be completed daily, with primary outcomes being duration of shoulder pain (number of days until recovery), peak shoulder pain intensity, and peak shoulder disability. Secondary outcomes include inflammatory markers, psychological mediators, and measures of pain sensitivity regulation., Conclusion: This pre-clinical trial builds on prior cohort studies and its completion will provide foundational data supporting efficacy and mechanisms of personalized interventions for individuals that may be at increased risk for developing chronic shoulder pain., Trial Registration: ClinicalTrials.gov registry, NCT02620579 (Registered on November 13, 2015)., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design Secondary analysis of prospectively collected data. Background An abundance of evidence has highlighted the influence of pain catastrophizing and fear avoidance on clinical outcomes. Less is known about the interaction of positive psychological resources with these pain-associated distress factors. Objective To assess whether optimism moderates the influence of pain catastrophizing and fear avoidance on 3-month clinical outcomes in patients with shoulder pain. Methods Data from 63 individuals with shoulder pain (mean ± SD age, 38.8 ± 14.9 years; 30 female) were examined. Demographic, psychological, and clinical characteristics were obtained at baseline. Validated measures were used to assess optimism (Life Orientation Test-Revised), pain catastrophizing (Pain Catastrophizing Scale), fear avoidance (Fear-Avoidance Beliefs Questionnaire physical activity subscale), shoulder pain intensity (Brief Pain Inventory), and shoulder function (Pennsylvania Shoulder Score function subscale). Shoulder pain and function were reassessed at 3 months. Regression models assessed the influence of (1) pain catastrophizing and optimism and (2) fear avoidance and optimism. The final multivariable models controlled for factors of age, sex, education, and baseline scores, and included 3-month pain intensity and function as separate dependent variables. Results Shoulder pain (mean difference, -1.6; 95% confidence interval [CI]: -2.1, -1.2) and function (mean difference, 2.4; 95% CI: 0.3, 4.4) improved over 3 months. In multivariable analyses, there was an interaction between pain catastrophizing and optimism (β = 0.19; 95% CI: 0.02, 0.35) for predicting 3-month shoulder function (F = 16.8, R 2 = 0.69, P<.001), but not pain (P = .213). Further examination of the interaction with the Johnson-Neyman technique showed that higher levels of optimism lessened the influence of pain catastrophizing on function. There was no evidence of significant moderation of fear-avoidance beliefs for 3-month shoulder pain (P = .090) or function (P = .092). Conclusion Optimism decreased the negative influence of pain catastrophizing on shoulder function, but not pain intensity. Optimism did not alter the influence of fear-avoidance beliefs on these outcomes. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2017;47(1):21-30. Epub 5 Nov 2016. doi:10.2519/jospt.2017.7068.

Objective: To identify novel combinations of genetic and psychological factors that predicted 12-month postoperative pain and disability outcomes following arthroscopic shoulder surgery., Methods: A prospective presurgical cohort (n = 150) was recruited to complete validated psychological questionnaires and have their DNA collected from saliva. DNA was genotyped for a priori selected genes involved with pain modulation (ADRB2, OPRM1, AVPR1A, GCH1, and KCNS1) and inflammation (IL1B, TNF/LTA, and IL6). The outcome measures of interest were the Brief Pain Inventory and Disabilities of the Arm, Shoulder, and Hand questionnaire. Followup for the cohort was at 3, 6, and 12 months postoperatively. After controlling for age, sex, race, and preoperative status, genetic and psychological factors were entered as main effects and interaction terms in separate general linear models for predicting postoperative pain and disability outcomes., Results: Seven interactions involving pain-modulatory genes were identified. Three provided strong statistical evidence for different outcomes, including KCNS1 and kinesiophobia for preoperative pain intensity, ADRB2 and depressive symptoms for postoperative course, and GCH1 and anxiety symptoms for 12-month pain-intensity outcome. Ten interactions involving inflammatory genes were identified. Three provided strong statistical evidence for the 12-month postoperative course outcome, including 2 different IL6 single-nucleotide polymorphism and pain catastrophizing, and IL6 and depressive symptoms., Conclusion: The current study identified novel genetic and psychological interactions that can be used in future studies to further understand the development of persistent postoperative pain and investigate the effectiveness of tailored treatment., (© 2016, American College of Rheumatology.)

Background: The STarT Back Screening Tool is a validated multidimensional screening measure and risk stratification tool for people with low back pain., Objective: The study objective was to compare relationships between a modified STarT Back Screening Tool (mSBT) and clinical and psychological measures in people with low back, neck, shoulder, and knee pain. The hypothesis was that the relationships between mSBT scores and clinical and psychological measure scores would be similar across the included musculoskeletal pain conditions., Design: A cross-sectional, secondary analysis was done in this study., Methods: Participants with low back (n=118), neck (n=92), shoulder (n=106), or knee (n=111) pain were recruited, and an mSBT was developed for use across the pain conditions. Separate hierarchical linear regression models were developed, with clinical (health status, pain intensity, and disability) and psychological (kinesiophobia, catastrophizing, fear avoidance, anxiety, depressive symptoms, and self-efficacy) measures as dependent variables. Demographic and pain region variables were entered in the first step, mSBT scores were entered in the second step, and pain region × mSBT interactions were entered in the last step., Results: In the final models, no interactions were identified, suggesting that dependent measure scores did not differ by pain region. The strongest contributor for all dependent variables was mSBT scores (β=|0.32|-|0.68|); higher mSBT scores were associated with poorer health status and self-efficacy and with higher levels of pain intensity, disability, kinesiophobia, catastrophizing, fear avoidance, anxiety, and depressive symptoms., Limitations: Generalizability was restricted to physical therapy outpatients with the included pain conditions. The mSBT used in this study is not ready for clinical implementation., Conclusions: The results of this study support the feasibility of using a single measure for concise risk assessment across different musculoskeletal pain conditions. Further longitudinal studies are needed to better direct the clinical use of an mSBT in people with low back, neck, shoulder, and knee pain., (© 2016 American Physical Therapy Association.)

Background: Shoulder pain and surgery are common among older adults. However, the extent to which older age affects recovery after shoulder surgery is not well understood., Objective: To assess influence of older age on postoperative recovery factors 3 and 6 months after shoulder arthroscopy., Design: Prospective cohort study., Setting: University-affiliated outpatient orthopedic surgical center., Patients: A convenience sample of 139 persons between 20 and 79 years of age who experienced shoulder pain, had musculoskeletal dysfunction based on imaging and physician assessment, and were scheduled for an arthroscopic shoulder procedure., Main Outcome Measures: Postoperative outcomes were compared among younger, middle-aged, and older adults before surgery and at 3 and 6 months after surgery using analysis of variance modeling. Movement-evoked pain and an experimental laboratory correlate of pain processing were assessed at each time point. The influence of older age on 3- and 6-month pain outcomes were determined via multivariate regression analyses after accounting for preoperative, intraoperative, and postoperative prognostic factors., Results: Older adults had higher movement-evoked pain intensity (F2,108 = 5.18, P = .007) and experimental pain response (F2,111 = 7.24, P = .001) at 3 months compared with young and middle-aged adults. After controlling for key prognostic factors, older age remained a positive predictor of 3-month movement-evoked pain (R(2) = 0.05; standardized [St.] β = 0.263, P = .031) and experimental pain response (R(2) = 0.07; St. β = 0.295, P = .014). Further, older age remained a positive predictor of movement-evoked pain at 6 months (R(2) = 0.04; St. β = 0.231, P = .004), despite no age group differences in outcome. Older age was found to be the strongest predictor of 3- and 6-month movement-evoked pain., Conclusion: Older adults may experience more pain related to movement, as well as endogenous pain excitation, in the first few months after shoulder arthroscopy. Future age-related research should consider use of movement-evoked pain intensity and experimental pain response as pain outcomes, as well as the utility of such measures in clinical care., (Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Study Design: Single-blind randomized trial., Objectives: To compare the effects of cervical and shoulder thrust manipulation (TM) and exercise on pain sensitivity, and to explore associations with clinical outcomes in patients with shoulder pain., Background: Experimental studies indicate that spinal TM has an influence on central pain processes, supporting its application for treatment of extremity conditions. Direct comparison of spinal and peripheral TM on pain sensitivity has not been widely examined., Methods: Seventy-eight participants with shoulder pain (36 female; mean ± SD age, 39.0 ± 14.5 years) were randomized to receive 3 treatments of cervical TM (n = 26), shoulder TM (n = 27), or shoulder exercise (n = 25) over 2 weeks. Twenty-five healthy participants (13 female; mean ± SD age, 35.2 ± 11.1 years) were assessed to compare pain sensitivity with that in clinical participants at baseline. Primary outcomes were changes in local (eg, shoulder) and remote (eg, tibialis anterior) pressure pain threshold and heat pain threshold occurring over 2 weeks. Secondary outcomes were shoulder pain intensity and patient-rated function at 4, 8, and 12 weeks. Analysis-of-variance models and partial-correlation analyses were conducted to examine comparative effects and the relationship between measures., Results: At baseline, clinical participants demonstrated lower local (mean difference, - 1.63 kg; 95% confidence interval [CI]: -2.40, -0.86) and remote pressure pain threshold (mean difference, -1.96 kg; 95% CI: -3.09, -0.82) and heat pain threshold (mean difference, -1.15°C; 95% CI: -2.06, -0.24) compared to controls, suggesting enhanced pain sensitivity. Following intervention, there were no between-group differences in pain sensitivity or clinical outcome (P>.05). However, improvements were noted, regardless of intervention, for pressure pain threshold (range of mean differences, 0.22-0.32 kg; 95% CI: 0.03, 0.43), heat pain threshold (range of mean differences, 0.30-0.58; 95% CI: 0.06, 0.96), pain intensity (range of mean differences, -1.79 to -1.45; 95% CI: -2.34, -0.94), and function (range of mean differences, 3.15-3.82; 95% CI: 0.69, 6.20) at all time points. We did not find an association between pain sensitivity changes and clinical outcome (P>.05). Conclusion Clinical participants showed enhanced pain sensitivity, but did not respond differently to cervical or peripheral TM. In fact, in this sample, cervical TM, shoulder TM, and shoulder exercise had similar pain sensitivity and clinical effects. The lack of association between pain sensitivity and clinical pain and function outcomes suggests different (eg, nonspecific) pain pathways for clinical benefit following TM or exercise., Level of Evidence: Therapy, level 1b.

Context: Athletic trainers use clinical pain and range of motion (ROM) to gauge recovery after musculoskeletal injury. Limited evidence to date suggests which shoulder ROM measures can predict symptomatic relief and functional recovery after delayed-onset muscle soreness (DOMS)., Objective: To determine whether shoulder passive internal rotation, passive external rotation, active abduction, and active flexion and evoked pain with abduction are associated with resting pain experienced after exercise-induced DOMS., Design: Descriptive laboratory study., Setting: Controlled research laboratory., Patients or Other Participants: A total of 110 healthy, right-hand-dominant participants (44 men: age = 25.39 ± 7.00 years, height = 178.93 ± 7.01 cm, weight = 78.59 ± 14.04 kg; 66 women: age = 22.98 ± 6.11 years, height = 164.64 ± 6.94 cm, weight = 61.86 ± 11.67 kg)., Intervention(s): Participants completed an exercise-induced DOMS protocol for the external rotators of the dominant shoulder to replicate muscle injury., Main Outcome Measure(s): Current resting pain was assessed daily for 96 hours using the Brief Pain Inventory. We evaluated functional recovery with measures of ROM in abduction, internal rotation, external rotation, and flexion. Evoked pain with active abduction was reported, and the pain rating served as the dependent variable in the regression model., Results: Impairment measures explained resting pain at 48 (R2 = 0.392) and 96 hours (R2 = 0.164). Abduction and internal-rotation ROM and evoked pain with abduction predicted resting pain at 48 hours (P < .001). At 96 hours, evoked pain with abduction of the injured arm (P < .001) was the significant contributor to resting pain., Conclusions: These models suggest that resting pain after experimentally induced DOMS occurs at 48 hours and is associated with specific ranges of motion and evoked pain with abduction.

Tailored treatment based on individual risk factors is an area with promise to improve options for pain relief. Musculoskeletal pain has a biopsychosocial nature, and multiple factors should be considered when determining risk for chronic pain. This study investigated whether subgroups comprised genetic and psychological factors predicted outcomes in preclinical and clinical models of shoulder pain. Classification and regression tree analysis was performed for an exercise-induced shoulder injury cohort (n = 190) to identify high-risk subgroups, and a surgical pain cohort (n = 150) was used for risk validation. Questionnaires for fear of pain and pain catastrophizing were administered before injury and preoperatively. DNA collected from saliva was genotyped for a priori selected genes involved with pain modulation (COMT and AVPR1A) and inflammation (IL1B and TNF/LTA). Recovery was operationalized as a brief pain inventory rating of 0/10 for current pain intensity and <2/10 for worst pain intensity. Follow-up for the preclinical cohort was in daily increments, whereas follow-up for the clinical cohort was at 3, 6, and 12 months postoperatively. Risk subgroups comprised the COMT high pain sensitivity variant and either pain catastrophizing or fear of pain were predictive of heightened shoulder pain responses in the preclinical model. Further analysis in the clinical model identified the COMT high pain sensitivity variant and pain catastrophizing subgroup as the better predictor. Future studies will determine whether these findings can be replicated in other anatomical regions and whether personalized medicine strategies can be developed for this risk subgroup.

Purpose: The pain experience has multiple influences, but little is known about how specific biological and psychological factors interact to influence pain responses. The current study investigated the combined influences of genetic (pro-inflammatory) and psychological factors on several preclinical shoulder pain phenotypes., Methods: An exercise-induced shoulder injury model was used, and a priori selected genetic (IL1B, TNF/LTA region, and IL6 single nucleotide polymorphisms (SNP)) and psychological (anxiety, depression symptoms, pain catastrophizing, fear of pain, and kinesiophobia) factors were included as the predictors of interest. The phenotypes were pain intensity (5-d average and peak reported on numerical rating scale), upper extremity disability (5-d average and peak reported on the Quick Disabilities of the Arm, Shoulder and Hand instrument), and duration of shoulder pain (d)., Results: After controlling for age, sex, and race, the genetic and psychological predictors were entered separately as main effects and interaction terms in regression models for each pain phenotype. Results from the recruited cohort (n = 190) indicated strong statistical evidence for the interactions between 1) TNF/LTA SNP rs2229094 and depression symptoms for average pain intensity and duration and 2) IL1B two SNP diplotype and kinesiophobia for average shoulder pain intensity. Moderate statistical evidence for prediction of additional shoulder pain phenotypes included interactions of kinesiophobia, fear of pain, or depressive symptoms with TNF/LTA rs2229094 and IL1B., Conclusions: These findings support the combined predictive ability of specific genetic and psychological factors for shoulder pain phenotypes by revealing novel combinations that may merit further investigation in clinical cohorts to determine their involvement in the transition from acute to chronic pain conditions.

Exercise-induced injury models are advantageous for studying pain since the onset of pain is controlled and both pre-injury and post-injury factors can be utilized as explanatory variables or predictors. In these studies, rest-related pain is often considered the primary dependent variable or outcome, as opposed to a measure of activity-related pain. Additionally, few studies include pain sensitivity measures as predictors. In this study, we examined the influence of pre-injury and post-injury factors, including pain sensitivity, for induced rest and activity-related pain following exercise induced muscle injury. The overall goal of this investigation was to determine if there were convergent or divergent predictors of rest and activity-related pain. One hundred forty-three participants provided demographic, psychological, and pain sensitivity information and underwent a standard fatigue trial of resistance exercise to induce injury of the dominant shoulder. Pain at rest and during active and resisted shoulder motion were measured at 48- and 96-hours post-injury. Separate hierarchical models were generated for assessing the influence of pre-injury and post-injury factors on 48- and 96-hour rest-related and activity-related pain. Overall, we did not find a universal predictor of pain across all models. However, pre-injury and post-injury suprathreshold heat pain response (SHPR), a pain sensitivity measure, was a consistent predictor of activity-related pain, even after controlling for known psychological factors. These results suggest there is differential prediction of pain. A measure of pain sensitivity such as SHPR appears more influential for activity-related pain, but not rest-related pain, and may reflect different underlying processes involved during pain appraisal.

Background: Measures of central pain processing like conditioned pain modulation and suprathreshold heat pain response (SHPR) have been described to assess different components of central pain modulatory mechanisms. Central pain processing potentially plays a role in the development of postsurgical pain, however, the role of conditioned pain modulation and SHPR in explaining postoperative clinical pain and disability is still unclear., Methods: Seventy-eight patients with clinical shoulder pain were included in this study. Patients were examined before shoulder surgery, at 3 months, and 6 months after surgery. The primary outcome measures were pain intensity and upper extremity disability., Results: Analyses revealed that the change score (baseline- 3 mo) of fifth pain rating of SHPR accounted for a significant amount of variance in 6-month postsurgical clinical pain intensity and disability after age, sex, preoperative pain intensity, and relevant psychological factors were considered., Conclusions: The present study suggests that baseline measures of central pain processing were not predictive of 6-month postoperative pain outcome. Instead, the 3-month change in SHPR might be a relevant factor in the transition to an elevated 6-month postoperative pain and disability outcomes. In patients with shoulder pain, the 3-month change in a measure of central pain processing might be a relevant factor in the transition to elevated 6-month postoperative pain and disability scores.

Objective: The aims of this study were to (1) examine the pattern of experimental pain responses in the affected and nonaffected extremities in patients with shoulder pain and (2) explore the intraindividual association between sensitization states derived from experimental pain testing., Methods: Experimental pain responses from 58 patients with shoulder pain (17 women, aged 18 to 52 y) were compared with those from 56 age-matched and sex-matched pain-free volunteers (16 women, aged 21 to 58 y). Experimental pain responses included pressure pain threshold (PPT), thermal pain threshold and tolerance, and suprathreshold heat pain response. Comparisons were made between the affected and nonaffected extremities of clinical participants and the average response of extremities in control participants. Peripheral and central sensitization indexes were computed for clinical participants using standardized scores and percentile cutoffs on the basis of the data from the control sample. Experimental pain responses in clinical participants observed beyond the 25th and 75th percentile of control sample responses were used for investigation of intraindividual association of sensitization states., Results: PPT at the acromion and masseter on the affected side of clinical participants were diminished compared with that on their nonaffected side (P<0.015). Bilateral sensitivity in clinical participants was noted for PPT at the acromion and suprathreshold heat pain response (P<0.015). Peripheral and central sensitization indexes demonstrated that individuals with shoulder pain present with variable patterns of peripheral and central sensitization., Conclusions: Collectively, experimental pain responses supported peripheral and central sensitization in response to pressure and thermal stimuli. No clear association was made between individuals exhibiting peripheral or central sensitization, thus suggesting heterogeneity in pain processing in this clinical population.

Unlabelled: Chronic pain is influenced by biological, psychological, social, and cultural factors. The current study investigated potential roles for combinations of genetic and psychological factors in the development and/or maintenance of chronic musculoskeletal pain. An exercise-induced shoulder injury model was used, and a priori selected genetic (ADRB2, COMT, OPRM1, AVPR1 A, GCH1, and KCNS1) and psychological (anxiety, depressive symptoms, pain catastrophizing, fear of pain, and kinesiophobia) factors were included as predictors. Pain phenotypes were shoulder pain intensity (5-day average and peak reported on numerical rating scale), upper extremity disability (5-day average and peak reported on the QuickDASH), and shoulder pain duration (in days). After controlling for age, sex, and race, the genetic and psychological predictors were entered as main effects and interaction terms in separate regression models for the different pain phenotypes. Results from the recruited cohort (N = 190) indicated strong statistical evidence for interactions between the COMT diplotype and 1) pain catastrophizing for 5-day average upper extremity disability and 2) depressive symptoms for pain duration. There was moderate statistical evidence for interactions for other shoulder pain phenotypes between additional genes (ADRB2, AVPR1 A, and KCNS1) and depressive symptoms, pain catastrophizing, or kinesiophobia. These findings confirm the importance of the combined predictive ability of COMT with psychological distress and reveal other novel combinations of genetic and psychological factors that may merit additional investigation in other pain cohorts., Perspective: Interactions between genetic and psychological factors were investigated as predictors of different exercise-induced shoulder pain phenotypes. The strongest statistical evidence was for interactions between the COMT diplotype and pain catastrophizing (for upper extremity disability) or depressive symptoms (for pain duration). Other novel genetic and psychological combinations were identified that may merit further investigation., (Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.)

Background: Several chronic pain populations have demonstrated decreased conditioned pain modulation (CPM). However there is still a need to investigate the stability of CPM paradigms before the measure can be recommended for implementation. The purpose of the present study was to assess whether shoulder pain intensity and gender influence CPM stability within and between sessions., Methods: This study examined two different musculoskeletal pain models, clinical shoulder pain and an experimental model of shoulder pain induced with eccentric exercise in healthy participants. Patients in the clinical cohort (N = 134) were tested before surgery and reassessed 3 months post-surgery. The healthy cohort (N = 190) was examined before inducing pain at the shoulder, and 48 and 96 hours later., Results: Our results provide evidence that 1) stability of inhibition is not related to changes in pain intensity, and 2) there are sex differences for CPM stability within and between days., Conclusions: Fluctuation of pain intensity did not significantly influence CPM stability. Overall, the more stable situations for CPM were females from the clinical cohort and males from the healthy cohort.

Unlabelled: Recent reports suggest deficits in conditioned pain modulation (CPM) and enhanced suprathreshold heat pain response (SHPR) potentially play a role in the development of chronic pain. The purpose of this study was to investigate whether central pain processing was altered in 2 musculoskeletal shoulder pain models. The goals of this study were to determine whether central pain processing: 1) differs between healthy subjects and patients with clinical shoulder pain; 2) changes with induction of exercise-induced muscle pain; and 3) changes 3 months after shoulder surgery. Fifty-eight patients with clinical shoulder pain and 56 age- and sex-matched healthy subjects were included in these analyses. The healthy cohort was examined before inducing EIMP, and 48 and 96 hours later. The clinical cohort was examined before shoulder surgery and 3 months later. CPM did not differ between the cohorts, however; SHPR was elevated for patients with shoulder pain compared to healthy controls. Induction of acute shoulder pain with EIMP resulted in increased shoulder pain intensity but did not change CPM or SHPR. Three months following shoulder surgery, clinical pain intensity decreased but CPM was unchanged from preoperative assessment. In contrast, SHPR was decreased and showed values comparable with healthy controls at 3 months. Therefore, the present study suggests that: 1) clinical shoulder pain is associated with measurable changes in central pain processing; 2) exercise-induced shoulder pain did not affect measures of central pain processing; and 3) elevated SHPR was normalized with shoulder surgery. Collectively our findings support neuroplastic changes in pain modulation were associated with decreases in clinical pain intensity only, and could be detected more readily with thermal stimuli., Perspective: Longitudinal studies involving quantitative sensory testing are rare. In exploring 2 musculoskeletal shoulder pain models (exercise-induced muscle pain and surgical pain), conditioned pain modulation was unchanged from pre- to post-assessment in both models. Suprathreshold heat pain response decreased after shoulder surgery and was comparable to healthy controls, suggesting this measure may be sensitive to decreases in clinical pain intensity., (Copyright © 2012 American Pain Society. Published by Elsevier Inc. All rights reserved.)

Study Design: Cross-sectional., Background: In the examination of patients with unilateral shoulder pain, pain provocation testing to compare the involved and uninvolved sides has been considered useful. However, side-to-side comparisons of experimental pain sensitivity in patients with unilateral shoulder pain are not widely reported in the literature., Objectives: To compare experimental pain sensitivity between the involved and uninvolved sides in patients with unilateral shoulder pain., Methods: In consecutive patients seeking operative treatment for shoulder pain, sensitivity measures of bilateral pressure pain threshold at the shoulder and forearm, and thermal pain threshold, tolerance, and temporal summation at the forearm, were examined. Pressure sensitivity was tested with a Fischer pressure algometer, and thermal sensitivity with a computer-controlled Medoc neurosensory analyzer. The involved and uninvolved sides were compared with an analysis of variance. Influence of sex and location of testing were considered as covariates in the analysis., Results: Fifty-nine consecutively recruited participants completed experimental pain sensitivity testing. Participants reported significantly lower pressure pain thresholds in the involved side compared to the uninvolved side (F1,56 = 4.96, P = .030). In addition, female compared to male participants demonstrated lower pressure pain thresholds in the bilateral shoulder regions (F1,56 = 10.84, P = .002). There was no difference in thermal pain sensitivity between sides. Average clinical pain intensity was negatively correlated with pressure pain threshold at the involved local site (r = -0.284, P = .029), indicating an influence of clinical pain intensity on local pressure pain., Conclusion: The results of this study provide evidence for higher experimental pressure pain sensitivity in the involved side of patients with unilateral shoulder pain and no difference between sides for thermal pain sensitivity. Females demonstrated higher pain sensitivity than males to pressure stimuli at the local shoulder region but not at the distal regions. Future studies should incorporate multiple stimuli when describing the pain profile of clinical populations.

Previous research demonstrates that men and women differ in the way that they perceive and process pain. Much of this work has been done in healthy adults with a lack of consensus in clinical pain populations. The purpose of this study was to investigate how men and women with shoulder pain differ in their experience of experimental and clinical pain and whether psychological processes differentially affect these responses. Fifty-nine consecutive subjects (24 women, 35 men) seeking operative treatment for shoulder pain were enrolled in this study. Subjects completed self report questionnaires to assess clinical pain, catastrophizing, anxiety and depression and underwent a series of experimental pain tests consisting of pressure pain, thermal pain (threshold and tolerance), and thermal temporal summation. Results indicated that women experienced greater clinical pain and enhanced sensitivity to pressure pain. Age did not affect the observed sex differences. There were no sex differences in psychological association with experimental and clinical pain in this cohort. The relationship between clinical and experimental pressure pain was stronger in women as compared to men. These findings offer insight into the interactions between biological and psychosocial influences of pain and how these interactions vary by sex., (Copyright © 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.)

Unlabelled: Quantitative sensory testing (QST) has become commonly used for the assessment of pain in subjects with clinical conditions. However, there is no consensus about which type of QST is the best predictor of clinical pain responses. The purposes of this study were to determine: a) the QST measure with the strongest association with clinical pain intensity; and b) if the QST measure continued to predict clinical pain intensity in a model including relevant psychological factors. Fifty-nine patients seeking treatment for shoulder pain underwent experimental pain assessment involving heat and pressure stimuli. The patients also completed validated questionnaires for pain intensity, pain catastrophizing, anxiety, and depression. The 5th pain rating in a series of suprathreshold heat pain stimuli accounted for a significant amount of variance in clinical pain intensity, with no other QST measure contributing to the model. The 5th pain rating remained a significant contributor to clinical pain intensity when psychological factors were included in the model. Furthermore, subjects with elevated 5th pain rating, pain catastrophizing, and depression scores had higher clinical pain intensity ratings in pre- and postoperative assessments. These data suggest that assessment of pain should include suprathreshold heat stimuli and psychological factors separately, and a combination of these factors may be predictive of pain intensity outcomes., Perspective: The current study provides evidence for a suprathreshold heat pain response as a clinically relevant QST measure for patients with shoulder pain, even after psychological factors were considered. The present findings suggest that the 5th pain rating from a series of suprathreshold stimuli, pain catastrophizing, and depression might play a role in predicting pain intensity outcomes., (Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the reliability and validity of 2 commonly used measures of pain related fear in patients with shoulder pain., Design: A preplanned secondary analysis of a prospective single-arm trial involving a repeated-measures design., Setting: Outpatient physical therapy clinics., Participants: Patients (N=80) with a primary report of shoulder pain., Intervention: All patients completed the outcome measures at baseline and at follow-up., Main Outcome Measures: Patients completed a modified Fear-Avoidance Beliefs Questionnaire (FABQ), the 11-item version of Tampa Scale of Kinesiophobia (TSK-11), and the Shoulder Pain and Disability Index (SPADI) at baseline and at a 48-hour follow-up. Patients were dichotomized as improved or stable at follow-up based on the Global Rating of Change., Results: Factor analysis indicated 3 stable factors for the FABQ and 1 stable factor for the TSK-11. Shoulder specific scoring for the FABQ and TSK-11 were used in subsequent analyses. Test-retest reliability intraclass correlation coefficient (ICC) was substantial for the FABQ and the TSK-11. The FABQ correlated significantly with SPADI pain and disability scores, while the TSK-11 correlated significantly only with SPADI pain scores. The shoulder-specific FABQ-W (work beliefs subscale) was a better than chance predictor of missing days of work during the 48-hour study period., Conclusions: The modified FABQ and TSK-11 may be appropriate for use in patients with shoulder pain. Shoulder-specific scoring of these measures resulted in substantial test-retest reliability, and the FABQ correlated with the SPADI for pain and disability. The FABQ also showed potential for prediction of short-term work loss in this sample. Pain-related fear may be an important variable in patients with shoulder pain and merits future consideration in longitudinal studies., (Copyright 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Study Design: Cross-sectional., Objectives: This study examined the baseline relationship of pain intensity, physical impairment, and pain-related fear to shoulder function., Background: There is no consensus regarding the influence psychological variable have on function and recovery in individuals with shoulder pathologies. While pain-related fear has been shown to predict disability for patients with low-back and cervical pain, this relationship has not been consistently reported for patients with shoulder pain., Methods and Measures: One hundred forty-two subjects (78 male, 64 female; mean age, 41.4 years) with nonoperative unilateral shoulder disorders were identified from a clinical database of impairment and outcome measures.Demographic information, duration of symptoms, mechanism of injury, pain intensity, pain-related fear, and range-of-motion (ROM) measures were collected. Self-report of function was measured with the Shoulder Pain and Disability Index (SPADI). Hierarchical regression analysis determined the proportions of explained variance in function., Results: Demographic variables (duration of symptoms, sex, age, and mechanism of injury) collectively contributed approximately 9% (P=.003) of the variance in function scores. Average pain intensity and flexion ROM contributed an additional 22% (P<.001) of the variance, and Tampa Scale of Kinesiophobia (TSK-11) scores contributed an additional 3% (P<.001). In the final parsimonious model, presence of symptoms longer than 3 months (beta=.23, P=.003), pain intensity (beta=.25, P=.002), shoulder flexion ROM index (beta=-.35, P=.001), and kinesiophobia (beta=.17, P=.026) explained 33% of the variance in SPADI function score (P<.001)., Conclusions: Presence of symptoms longer than 3 months, average pain intensity, flexion ROM index (strongest contributor in multivariate model), and fear-of-pain scores all contributed to baseline shoulder function. The immediate clinical relevance of these findings is unclear but they do provide direction for prospective studies.

Unlabelled: Pain-related fear and pain catastrophizing are 2 central psychologic factors in fear-avoidance models. Our previous studies in healthy subjects indicated that pain-related fear, but not pain catastrophizing, was associated with cold pressor pain outcomes. The current study extends previous work by investigating pain-related fear and pain catastrophizing in a group of subjects with shoulder pain, and included concurrent measures of experimental and clinical pain. Fifty nine consecutive subjects seeking operative treatment of shoulder pain were enrolled in this study (24 women, mean age = 50.4, SD = 14.9). Subjects completed validated measures of pain-related fear, pain catastrophizing, and clinical pain intensity and then underwent a cold pressor task to determine experimental pain sensitivity. Multivariate regression models used sex, age, pain-related fear, and pain catastrophizing to predict experimental pain sensitivity and clinical pain intensity. Results indicated that only pain-related fear uniquely contributed to variance in experimental pain sensitivity (beta = -.42, P < .01). In contrast, sex (beta = -.29, P = .02) and pain catastrophizing (beta = .43, P < .01) uniquely contributed to variance in clinical pain intensity. These data provide additional support for application of fear-avoidance models to subjects with shoulder pain. Our results also suggest that pain-related fear and pain catastrophizing may influence different components of the pain experience, providing preliminary support for recent theoretical conceptualizations of the role of pain catastrophizing., Perspective: This study provided additional information on how specific psychological variables potentially influence experimental and clinical pain. In this sample of subjects with shoulder pain, we replicated findings from our previous studies involving healthy subjects, as fear of pain was uniquely associated with experimental pain sensitivity. In contrast, pain catastrophizing emerged as the sole psychological variable related to clinical pain intensity.

Objective: The experience of pain is believed to be influenced by psychologic and genetic factors. A previous study suggested pain catastrophizing and catechol-O-methyltransferase (COMT) genotype influenced clinical pain ratings for patients seeking operative treatment of shoulder pain. This study investigated whether these same psychologic and genetic factors predicted responses to induced shoulder pain., Methods: Participants (n=63) completed self-report questionnaires and had COMT genotype determined before performing a standardized fatigue protocol to induce delayed onset muscle soreness. Then, shoulder pain ratings, self-report of upper-extremity disability ratings, and muscle torque production were reassessed 24, 48, and 72 hours later., Results: This cohort consisted of 35 women and 28 men, with a mean age of 20.9 years (SD=1.7). The frequency of COMT diplotypes was 42 with "high COMT enzyme activity" (low pain sensitivity group) and 21 with "low COMT enzyme activity" (average pain sensitivity/high pain sensitivity group). A hierarchical regression model indicated that an interaction between pain catastrophizing and COMT diplotype was the strongest unique predictor of 72-hour pain ratings. The same interaction was not predictive of self-report of disability or muscle torque production at 72 hours. The pain catastrophizingxCOMT diplotype interaction indicated that participants with high pain catastrophizing and low COMT enzyme activity (average pain sensitivity/high pain sensitivity group) were more likely (relative risk=3.5, P=0.025) to have elevated pain intensity ratings (40/100 or higher)., Discussion: These findings from an experimental model converge with those from a surgical cohort and provide additional evidence that the presence of elevated pain catastrophizing and COMT diplotype indicative of low COMT enzyme activity have the potential to increase the risk of developing chronic pain syndromes.

The experience of pain is believed to be influenced by social, cultural, environmental, psychological, and genetic factors. Despite this assertion, few studies have included clinically relevant pain phenotypes when investigating interactions among these variables. This study investigated whether psychological variables specific to fear-avoidance models and catechol-O-methyltransferase (COMT) genotype influenced pain ratings for a cohort of patients receiving operative treatment of shoulder pain. Patients (n=58) completed questionnaires and had COMT genotype determined pre-operatively. Then, shoulder pain ratings were collected 3-5 months post-operatively. This cohort consisted of 24 females and 34 males, with mean age of 50.3 (SD=15.0) and pre-operative pain rating of 4.5/10 (SD=1.8). The frequency of COMT diplotypes was 34 with "high COMT activity" (LPS group) and 24 with "low COMT activity" (APS/HPS group). Preliminary analysis indicated that of all the fear-avoidance variables considered (fear of pain, kinesiophobia, pain catastrophizing, and anxiety), only pain catastrophizing was a unique contributor to clinical pain ratings. A hierarchical regression model indicated that an interaction between pain catastrophizing and COMT diplotype contributed additional variance in pre-operative pain ratings. The pain catastrophizingxCOMT diplotype interaction demonstrated predictive validity as patients with high pain catastrophizing and low COMT activity (APS/HPS group) were more likely (RR=6.8, 95% CI=2.8-16.7) to have post-operative pain ratings of 4.0/10 or higher. Our findings suggest that an interaction between pain catastrophizing and COMT diplotype has the potential to influence pain ratings in patients seeking operative treatment of their shoulder pain.

The current literature offers limited evidence supporting sport-specific plyometric rehabilitation for young throwing athletes. The purposes of this case report were to 1) describe the focused differential diagnosis of a young throwing athlete with shoulder pain and 2) use previously validated, region-specific, health-related quality of life measures to describe clinical outcomes for a rehabilitation program that included sport-specific, plyometric training. The 13-year-old male patient presented in this case report experienced a sudden onset of right shoulder pain while pitching in a baseball game. On physical examination, this patient demonstrated shoulder pain, pain with palpation of the infraspinatus and teres minor muscles, decreased strength of the infraspinatus and teres minor with resultant impaired rotator cuff performance, and signs consistent with anterior shoulder instability. Early rehabilitation consisted of modalities for pain relief and therapeutic exercises to improve strength. In the return to sport phase of rehabilitation, the patient performed sport-specific plyometric exercises that were progressed in difficulty based on the patient's report of pain and muscle soreness. Health-related quality of life was assessed by using the Shoulder Pain and Disability Index (SPADI) and the sports module of the Disability of Arm, Shoulder and Hand (DASH) questionnaires. A standard error of measurement (SEM)-based criterion was used to determine if the patient demonstrated meaningful changes in outcome measures. The patient did not demonstrate meaningful improvement in pain or general disability with the SPADI. The patient did demonstrate a meaningful improvement in sport-specific function with the DASH. It is possible that sport-specific plyometric rehabilitation may have provided additional benefit for this athlete's ability to return to sport, but definite conclusions regarding treatment effectiveness are limited by the case report design. Properly designed studies investigating the benefits of sport-specific plyometric rehabilitation are warranted before the effectiveness of these techniques can be determined.

Objectives: This study investigated whether anxiety, fear of pain, or pain catastrophizing were predictive of pain-related outcomes after induced delayed onset muscle soreness (DOMS) at the shoulder., Methods: Healthy participants (19 males and 23 females) were eligible for participation if they had (a) no history of neck or shoulder pain, (b) no sensory or motor impairments of the upper-extremity, (c) not regularly participating in upper-extremity weight training, (d) not currently or regularly taking pain medication, and (e) no history of upper-extremity surgery. Participants completed self-report measures for fear of pain, pain catastrophizing, and anxiety. Then, participants underwent a standard fatigue protocol to induce DOMS in the shoulder external rotator muscles. Participants were reassessed 24 hours after DOMS induction on clinical and evoked pressure pain reports, muscle force production, self-report of upper-extremity disability, and kinesiophobia. Stepwise regression models considered sex, anxiety, pain intensity, fear of pain, and pain catastrophizing as outcome predictors., Results: Fear of pain alone explained 16% (P=0.008) of the variance in clinical pain and 10% (P=0.047) evoked pressure pain intensity. Clinical pain intensity alone explained 11% (P<0.031) of the variance in muscle force production. Clinical pain intensity and fear of pain explained 50% (P<0.001) of the variance in upper-extremity disability, whereas fear of pain and sex accounted for 26% (P=0.005) of the variance in kinesiophobia., Conclusions: With the exception of muscle force production, fear of pain had a consistent influence on shoulder DOMS outcomes, even after controlling for pain intensity. This study suggests fear of pain may be a relevant psychologic factor to consider in clinical studies investigating the development and treatment of chronic shoulder pain.

Background: Despite similar outcomes for surgery and physical therapy (PT), the number of surgeries to treat rotator cuff related shoulder pain (RCRSP) is increasing. Interventions designed to enhance treatment expectations for PT have been shown to improve patient expectations, but no studies have explored whether such interventions influence patient reports of having had surgery, or being scheduled for surgery. The purpose of this randomized clinical trial was to examine the effect of a cognitive behavioral intervention aimed at changing expectations for PT on patient-report of having had or being scheduled for surgery and on the outcomes of PT. Methods: The Patient Engagement, Education, and Restructuring of Cognitions (PEERC) intervention, was designed to change expectations regarding PT. PEERC was evaluated in a randomized, pragmatic "add-on" trial in by randomizing patients with RCRSP to receive either PT intervention alone (PT) or PT + PEERC. Fifty-four (54) individuals, recruited from an outpatient hospital-based orthopedic clinic, were enrolled in the trial (25 randomized to PT, 29 randomized to PT + PEERC). Outcomes assessed at enrollment, 6 weeks, discharge, and six months after discharge included the patient report of having had surgery, or being scheduled for surgery (primary) and satisfaction with PT outcome, pain, and function (secondary outcomes). Results: The average age of the 54 participants was 51.81; SD = 12.54, and 63% were female. Chronicity of shoulder pain averaged 174.61 days; SD = 179.58. Study results showed that at the time of six months follow up, three (12%) of the participants in the PT alone group and one (3.4%) in the PT + PEERC group reported have had surgery or being scheduled for surgery (p =.32). There were no significant differences between groups on measures of satisfaction with the outcome of PT (p =.08), pain (p =.58) or function (p =.82). Conclusions: In patients with RCRSP, PT plus the cognitive behavioral intervention aimed at changing expectations for PT provided no additional benefit compared to PT alone with regard to patient report of having had surgery, or being scheduled to have surgery, patient reported treatment satisfaction with the outcome of PT, or improvements in pain, or function. Trial registration: The trial is registered on ClinicalTrials.gov: NCT 03353272 (27/11/2017). [ABSTRACT FROM AUTHOR]

Introduction: Biochemical biomarkers may provide insight into musculoskeletal pain reported at individual or multiple body sites. The purpose of this study was to determine if biomarkers or pressure-pain threshold (PPT) were associated with individual or multiple sites of pain. Methods: This cross-sectional analysis included 689 community-based participants. Self-reported symptoms (ie, pain, aching, or stiffness) were ascertained about the neck, upper back/thoracic, low back, shoulders, elbows, wrist, hands, hips, knees, ankles, and feet. Measured analytes included CXCL-6, RANTES, HA, IL-6, BDNF, OPG and NPY. A standard dolorimeter measured PPT. Logistic regression was used determine the association between biomarkers and PPT with individual and summed sites of pain. Results: Increased IL-6 and HA were associated with knee pain (OR=1.30, 95% CI 1.03, 1.64) and (OR=1.32, 95% CI 1.01, 1.73) respectively; HA was also associated with elbow/wrist/hand pain (OR=1.60, 95% CI 1.22, 2.09). Those with increased NPY levels were less likely to have shoulder pain (OR=0.56, 95% CI 0.33, 0.93). Biomarkers HA (OR=1.50, 95% CI 1.07, 2.10), OPG (OR=1.74, 95% CI 1.00, 3.03), CXCL-6 (OR=1.75, 95% CI 1.02, 3.01) and decreased PPT (OR=3.97, 95% CI 2.22, 7.12) were associated with multiple compared to no sites of pain. Biomarker HA (OR=1.57, 95% CI 1.06, 2.32) and decreased PPT (OR=3.53, 95% CI 1.81, 6.88) were associated with multiple compared to a single site of pain. Conclusion: Biomarkers of inflammation (HA, OPG, IL-6 and CXCL-6), pain (NPY) and PPT may help to understand the etiology of single and multiple pain sites. [ABSTRACT FROM AUTHOR]

Psychological distress is associated with disability and quality of life for patients with shoulder pain. However, uncertainty around heterogeneity of psychological distress has limited the adoption of shoulder care models that address psychological characteristics. In a cohort of patients with shoulder pain, our study sought to (1) describe the prevalence of various subtypes of psychological distress; (2) evaluate associations between psychological distress and self-reported shoulder pain, disability, and function; and (3) determine differences in psychological distress profiles between patients receiving nonoperative vs. operative treatment. The sample included 277 patients who were evaluated in clinic by a shoulder surgeon and completed the Optimal Screening for Prediction of Referral and Outcome Yellow Flag Assessment Tool (OSPRO-YF) from 2019 to 2021. This tool categorizes maladaptive and adaptive psychological traits, and the number of yellow flags (YFs) ranges from 0 to 11, with higher YF counts indicating higher pain-related psychological distress. Operative and nonoperative cohorts were compared using χ2 test and Student t test. Linear regression was used to evaluate the association between pain, disability, and YFs, whereas Poisson regression evaluated the association between operative treatment and psychological distress. K-means cluster analysis was performed to propose potential psychological distress phenotypes. Two hundred fifty-one patients (91%) had at least 1 YF on the OSPRO-YF tool, with a mean number of 6 ± 3.5 YFs. YFs in unhelpful coping (85%) and helpful coping domains (78%) were most prevalent. The number of YFs was significantly associated with baseline shoulder pain (P <.001), Single Assessment Numeric Evaluation (P <.001), and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (P <.001) scores. Comparing operative and nonoperative cohorts, the operative cohort had a significantly higher mean number of YFs (6.5 vs. 5.6, P =.035), presence of any YF (94.3% vs. 85.7%, P =.015), and presence of YFs within the unhelpful coping domain (91.8% vs. 75.6%, P <.001). Three phenotypes were described, corresponding to low, moderate, and severe psychological distress (P <.001), with females (P =.037) and smokers (P =.018) associated with higher psychological distress phenotypes. YFs, particularly within the unhelpful coping and helpful coping domains, were highly prevalent in a cohort of patients presenting to a shoulder surgeon's clinic. Additionally, operative patients were found to have a significantly higher rate of YFs across multiple dimensions of psychological distress. These findings stress the importance of routine attentiveness to multiple dimensions of pain-related psychological distress in shoulder populations, which can provide an opportunity to reinforce healthy interpretation of pain while minimizing distress in appropriately identified patients. [ABSTRACT FROM AUTHOR]

Objectives: Transcutaneous electrical nerve stimulation (TENS) is commonly used for reducing musculoskeletal pain to improve function. However, peripheral nerve stimulation using TENS can alter muscle motor output. Few studies examine motor outcomes following TENS in a human pain model. Therefore, this study investigated the influence of TENS sensory stimulation primarily on motor output (strength) and secondarily on pain and disability following exercise‐induced delayed‐onset muscle soreness (DOMS). Methods: Thirty‐six participants were randomized to a TENS treatment, TENS placebo, or control group after completing a standardized DOMS protocol. Measures included shoulder strength, pain, mechanical pain sensitivity, and disability. TENS treatment and TENS placebo groups received 90 minutes of active or sham treatment 24, 48, and 72 hours post‐DOMS. All participants were assessed daily. Results: A repeated measures analysis of variance and post‐hoc analysis indicated that, compared to the control group, strength remained reduced in the TENS treatment group (48 hours post‐DOMS, P < 0.05) and TENS placebo group (48 hours post‐DOMS, P < 0.05; 72 hours post‐DOMS, P < 0.05). A mixed‐linear modeling analysis was conducted to examine the strength (motor) change. Randomization group explained 5.6% of between‐subject strength variance (P < 0.05). Independent of randomization group, pain explained 8.9% of within‐subject strength variance and disability explained 3.3% of between‐subject strength variance (both P < 0.05). Discussion: While active and placebo TENS resulted in prolonged strength inhibition, the results were nonsignificant for pain. Results indicated that higher pain and higher disability were independently related to decreased strength. Regardless of the impact on pain, TENS, or even the perception of TENS, may act as a nocebo for motor output. [ABSTRACT FROM AUTHOR]

Background: Shoulder pain and surgery are common among older adults. However, the extent to which older age affects recovery after shoulder surgery is not well understood.Objective: To assess influence of older age on postoperative recovery factors 3 and 6 months after shoulder arthroscopy.Design: Prospective cohort study.Setting: University-affiliated outpatient orthopedic surgical center.Patients: A convenience sample of 139 persons between 20 and 79 years of age who experienced shoulder pain, had musculoskeletal dysfunction based on imaging and physician assessment, and were scheduled for an arthroscopic shoulder procedure.Main Outcome Measures: Postoperative outcomes were compared among younger, middle-aged, and older adults before surgery and at 3 and 6 months after surgery using analysis of variance modeling. Movement-evoked pain and an experimental laboratory correlate of pain processing were assessed at each time point. The influence of older age on 3- and 6-month pain outcomes were determined via multivariate regression analyses after accounting for preoperative, intraoperative, and postoperative prognostic factors.Results: Older adults had higher movement-evoked pain intensity (F2,108 = 5.18, P = .007) and experimental pain response (F2,111 = 7.24, P = .001) at 3 months compared with young and middle-aged adults. After controlling for key prognostic factors, older age remained a positive predictor of 3-month movement-evoked pain (R(2) = 0.05; standardized [St.] β = 0.263, P = .031) and experimental pain response (R(2) = 0.07; St. β = 0.295, P = .014). Further, older age remained a positive predictor of movement-evoked pain at 6 months (R(2) = 0.04; St. β = 0.231, P = .004), despite no age group differences in outcome. Older age was found to be the strongest predictor of 3- and 6-month movement-evoked pain.Conclusion: Older adults may experience more pain related to movement, as well as endogenous pain excitation, in the first few months after shoulder arthroscopy. Future age-related research should consider use of movement-evoked pain intensity and experimental pain response as pain outcomes, as well as the utility of such measures in clinical care. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: Literature review and cross-sectional study. BACKGROUND: Direct access to physical therapy necessitates greater responsibility to determine appropriateness of care by recognizing the potential for concomitant disease or systemic involvement. Recent research has identified excessive variability in the reporting of red flag symptoms. An initial step to improve the identification of red flag symptoms is the development of a standardized screening tool. OBJECTIVE: To describe the development of a review-of-systems screening tool appropriate for use by orthopaedic physical therapists. METHODS: First, a red flag symptom item bank was compiled from a systematic literature review to allow for further psychometric testing and development of a screening tool. Second, physical therapists in 11 outpatient clinics recruited patients presenting with primary complaints of neck, shoulder, low back, or knee pain. Patients completed the red flag symptom item bank and standard questionnaires for comorbidities, negative mood, quality of life, pain, and function. The development of the screening tool involved identifying and combining different 3-item sets that characterized the highest number of patients reporting at least 1 positive symptom response (operationally defined as "red flag symptom responder"). RESULTS: The literature search yielded 103 studies that met the inclusion criteria, and the final item bank consisted of 97 items representing 8 body systems. Four hundred thirty-one patients with primary complaints of neck (n = 93), shoulder (n = 108), low back (n = 119), or knee (n = 111) disorders contributed to the cross-sectional study. The number of red flag symptom responders was 393 of 431 (91.2%). These patients were older, more likely to be female, had lower income, and were more likely to report neck or back pain (all, P<.05). A 10-item review-of-systems screening tool correctly identified 372 of 393 (94.7%) responders, and a 23-item version identified all 393 (100%) responders. The review-of-systems screening tools and the complete 97-item bank had similar correlations with concurrent clinical measures, except for depressive symptoms. CONCLUSION: Concise red flag symptom identification appears to be feasible in outpatient orthopaedic physical therapy settings. Future research will determine how this review-of-systems screening tool needs refinement for different patient populations and whether it predicts clinical outcomes or the need for referral to other providers. [ABSTRACT FROM AUTHOR]