Functional and Structural Neuroplastic Changes Related to Sensitization Proxies in Patients with Osteoarthritis: A Systematic Review.

OBJECTIVE: Several reports in literature have identified sensitization as a possible basis for the enhanced pain reactions associated with osteoarthritis (OA). The aim of this current systematic review is to summarize functional and structural brain changes associated with surrogate sensitization parameters assessed in patients with OA-related pain. DESIGN: Systematic review. SUBJECTS: Patients with OA related pain. METHODS: A literature search was conducted systematically in MEDLINE, CINAHL, EMBASE databases for human studies up to December 2019. Articles were included if they assessed brain imaging and sensitization parameters (quantitative sensory testing and questionnaires) in adults with OA-related pain. Methodological quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) score. RESULTS: Five studies reporting on 138 patients were included in this review. The MINORS scale yielded mean scores of 8.5/16 and 12.3/24, for the cohort and case-control studies respectively. Four low-quality studies suggest a greater pain matrix activation associated with clinical measures of sensitization in patients with OA, while another study underlined the presence of structural changes (reduced gray matter volume) in the cortical areas involved in the nociceptive processing possible also related to sensitization. CONCLUSIONS: This review shows conflicting evidence for structural and functional neuroplastic brain changes related to sensitization proxies in patients with OA.

Physical therapists' attitudes are associated with their confidence in and the frequency with which they engage in prescription opioid medication misuse management practices with their patients. A cross-sectional study.

Background: In the US, prescription opioid medication misuse (POMM) necessitates engagement of physical therapists (PTs). We (1) evaluated the attitudes of (PT) related to their management of patients with POMM and (2) examined the association between these attitudes and PTs confidence in POMM-related management abilities and the frequency with which they engaged in POMM-related management practices. Methods: We conducted a national survey of PTs that included a modified Drug and Drug Problems Perception Questionnaire (DDPPQ). Confidence in POMM-related abilities and the frequency of engaging in POMM-related management practices were measured. Logistic regression evaluated the association between the DDPPQ subscales (role adequacy, role legitimacy, role self-esteem, role support, job satisfaction) and confidence and frequency outcomes. Results: The analysis included 402 respondents. Role adequacy and legitimacy subscales were associated with confidence and frequency outcomes (p<.05), indicating that more favorable role adequacy and legitimacy attitudes are associated with greater odds of having more confidence in POMM-related management abilities and of engaging in more frequent POMM-related management practices. Conclusions: PTs with a greater sense of preparedness to engage in POMM-related management were more likely to report greater confidence in POMM-related management abilities and engage in POMM-related management practices with greater frequency.

An Examination of Day-to-Day and Intraindividual Pain Variability in Low Back Pain.

OBJECTIVE: This study aimed to capture day-to-day changes in pain intensity in individuals with low back pain (LBP), which may be indicative of patients' ability to modulate their pain levels. A secondary aim was to explore the presence of latent subgroups characterized by pain level, intraindividual pain variability, and change in pain over a 14-day period. SUBJECTS: Participants were 54 adults with self-reported LBP recruited from outpatient physical therapy clinics and the community. METHODS: Over the course of 14 days, participants completed daily measures of pain intensity, catastrophizing, pain self-efficacy, and negative affect. Change in pain intensity as well as total amount of intraindividual pain variability were also calculated. RESULTS: Daily increases in maladaptive coping and affective responses (i.e., higher catastrophizing, higher negative affect, lower pain self-efficacy) were associated with increases in pain intensity. A hierarchical cluster analysis revealed three subgroups: 1) moderate pain intensity, moderate pain variability, increase in pain over time; 2) low pain intensity, low pain variability, no change in pain over time; and 3) moderate pain intensity, high pain variability, decrease in pain over time. Cluster 2 demonstrated more adaptive coping and affective responses at baseline and during the 14-day period, and clusters 1 and 3 did not differ in their coping or affective responses. CONCLUSIONS: These findings provide support that day-to-day changes in pain, coping, and affective responses are meaningful and provide additional evidence of pain variability as a potential phenotypic characteristic.

Effects of High-Intensity Laser Therapy on Pain Sensitivity and Motor Performance in Patients with Thumb Carpometacarpal Joint Osteoarthritis: A Randomized Controlled Trial.

OBJECTIVE: To examine the effects of high-intensity laser therapy (HILT) on pain sensitivity and motor performance in patients with thumb carpometacarpal (CMC) osteoarthritis (OA). DESIGN: Prospective, triple-blinded, randomized, placebo-controlled trial. SETTING: Private practice, Malaga, Spain. SUBJECTS: Forty-three patients (mean ± SD age = 71 ± 12 years) with a diagnosis of thumb CMC OA grade 1-2 were randomized to the control group (N = 21) or experimental group (N = 22). METHODS: The experimental group (ExpG) received high-intensity laser therapy (HILT), and the control group (ConG) received a placebo treatment. The outcome measures were pain intensity (visual analog scale) and key pinch strength measurements (dynamometer). All outcome measures were collected at baseline, immediately following the intervention, at four weeks, and at 12 weeks following the intervention. RESULTS: Analysis of variance revealed a group × time interaction (F = 40.8, P < 0.001) for pain intensity, with those patients receiving LT experiencing a greater reduction in pain compared with those receiving placebo therapy at the end of the intervention (P < 0.001), as well as at 12 weeks after the intervention. Although mean values in the ExpG were higher than in the ConG for key pinch at assessment, these differences were not statistically significant. CONCLUSIONS: HILT effectively diminishes pain intensity when used as an isolated treatment for patients with thumb CMC OA, but the effect of treatment decreases after 12 weeks.

Pressure algometry and palpation of the upper limb peripheral nervous system in subjects with hand osteoarthritis are repeatable and suggest central changes.

STUDY DESIGN: Case-control study. INTRODUCTION: A subset of patients with hand osteoarthritis (OA) shows evidence of central pain phenotypes. PURPOSE OF THE STUDY: To examine whether differences exist in experimental pain responses in the affected and nonaffected sides of patients with unilateral hand OA. To investigate the test-retest reliability of pressure algometry and manual digital palpation in patients with unilateral hand OA. METHODS: The hand OA group consisted of 20 patients, and the control group consisted of 20 healthy subjects. Pressure pain threshold (PPT) measurements were made 2 times, consisting of 3 repeat trials, each using computerized algometry and manual digital palpation. Grip and key strength (dynamometer), pain (visual analog scale), and function (Disabilities of the Arm, Shoulder and Hand [short version]) were also measured. The 2-way analysis of variance was conducted to determine the differences between sides and groups. Intraclass correlation coefficient (ICC) and standard error of measurement were calculated. RESULTS: Patients with hand OA had decreased PPTs over the thumb carpometacarpal joint as well as radial and median nerves compared with controls (all P < .01). No significant group effect by side interaction was detected for any measure. The minimal detectable change values needed to detect change in subjects with hand OA were C5-C6 joint (0.3-0.5 kg/cm2), carpometacarpal joint (0.3-0.5 kg/cm2), hamate bone (0.2-0.4 kg/cm2), radial nerve (0.2-0.8 kg/cm2), median nerve (0.3-0.6 kg/cm2), and ulnar nerve (0.2-0.4 kg/cm2) for PPT. Test-retest reliability was calculated for both hands of participants with OA (ICC, 0.98-0.99) and healthy participants (ICC, 0.74-0.99). DISCUSSION: Although pressure algometry and manual digital palpation are techniques already used in previous studies and have been shown to be reproducible and moderately reliable for joint palpation, this current study suggests that pressure algometry and manual digital palpation could also be reliable methods of determining nerve sensitivity of the radial, ulnar and median nerves in subjects with hand OA. CONCLUSIONS: Hyperalgesia in patients with hand OA might be associated with clinical measures, and bilateral signs in unilateral OA could suggest central changes.

Motoneuron Function Does not Change Following Whole-Body Vibration in Individuals With Chronic Ankle Instability.

CONTEXT: Following a lateral ankle sprain, ∼40% of individuals develop chronic ankle instability (CAI), characterized by recurrent injury and sensations of giving way. Deafferentation due to mechanoreceptor damage postinjury is suggested to contribute to arthrogenic muscle inhibition (AMI). Whole-body vibration (WBV) has the potential to address the neurophysiologic deficits accompanied by CAI and, therefore, possibly prevent reinjury. OBJECTIVE: To determine if an acute bout of WBV can improve AMI and proprioception in individuals with CAI. DESIGN AND PARTICIPANTS: The authors examined if an acute bout of WBV can improve AMI and proprioception in individuals with CAI with a repeated-measures design. A total of 10 young adults with CAI and 10 age-matched healthy controls underwent a control, sham, and WBV condition in randomized order. SETTING: Biomechanics laboratory. INTERVENTION: WBV. MAIN OUTCOME MEASURES: Motoneuron pool recruitment was assessed via Hoffmann reflex (H-reflex) in the soleus. Proprioception was evaluated using ankle joint position sense at 15° and 20° of inversion. Both were assessed prior to, immediately following, and 30 minutes after the intervention (pretest, posttest, and 30mPost, respectively). RESULTS: Soleus maximum H-reflex:M-response (H:M) ratios were 25% lower in the CAI group compared with the control group (P = .03). Joint position sense mean constant error did not differ between groups (P = .45). Error at 15° in the CAI (pretest 0.8 [1.6], posttest 2.0 [2.8], 30mPost 2.0 [1.9]) and control group (pretest 0.8 [2.0], posttest 0.6 [2.9], 30mPost 0.5 [2.1]) did not improve post-WBV. Error at 20° did not change post-WBV in the CAI (pretest 1.3 [1.7], posttest 1.0 [2.4], 30mPost 1.5 [2.2]) or control group (pretest -0.3 [3.0], posttest 0.8 [2.1], 30mPost 0.6 [1.8]). CONCLUSION: AMI is present in the involved limb of individuals with CAI. The acute response following a single bout of WBV did not ameliorate the presence of AMI nor improve proprioception in those with CAI.

Impact of expectations on functional recovery in individuals with chronic shoulder pain.

STUDY DESIGN: Retrospective cohort. OBJECTIVES: To examine general expectations for treatment by physical therapists and specific expectations for common interventions in patients with shoulder pain. A secondary objective was to assess the extent to which patients' general and specific expectations for treatment affect clinical outcomes. METHODS: We performed a secondary analysis of data from a clinical trial of interventions for shoulder pain. Prior to beginning treatment for shoulder pain, 140 patients were asked their general expectations of benefit and their specific expectations for individual interventions. Next we examined how these expectations related to the patients' ratings of the success of treatment at one and six months after treatment. RESULTS: Patients had positive general expectations for treatment by a physical therapist. Specific manual therapy interventions of range of motion and strengthening had the highest proportion of patients who expected these interventions to significantly improve shoulder pain. Seventy-two patients (58%) reported themselves to be improved using the global rating of change (GROC) at one month and six months. In the full model predicting one-month GROC, only the expectation of moderate relief (p = 0.012) and body mass index (BMI) (p = 0.013) had significant effects. Overall, the Shoulder Pain and Disability Index (SPADI) significantly decreased over time (p = 0.004); however, a significant interaction did occur between time and BMI (p = 0.021). DISCUSSION: Patients expect common interventions used by physical therapists to be effective to manage shoulder pain. In conclusion, patients with shoulder pain had high general expectations for physical therapy. LEVEL OF EVIDENCE: Prognosis, level 2b.

A value proposition for early physical therapist management of neck pain: a retrospective cohort analysis.

BACKGROUND: Neck pain is one of the most common reasons for entry into the healthcare system. Recent increases in healthcare utilization and medical costs have not correlated with improvements in health. Therefore there is a need to identify management strategies for neck pain that are effective for the patient, cost efficient for the payer and provided at the optimal time during an episode of neck pain. METHODS: One thousand five hundred thirty-one patients who underwent physical therapist management with a primary complaint of non-specific neck pain from January 1, 2008 to December 31, 2012 were identified from the Rehabilitation Outcomes Management System (ROMS) database at Intermountain Healthcare. Patients reporting duration of symptoms less than 4 weeks were designated as undergoing "early" management and patients with duration of symptoms greater than 4 weeks were designated as receiving "delayed" management. These groups were compared using binary logistic regression to examine odds of achieving Minimal Clinically Important Difference (MCID) on the Neck Disability Index (NDI) and Numerical Pain Rating Scale (NPRS). Separate generalized linear modeling examined the effect of timing of physical therapist management on the metrics of value and efficiency. RESULTS: Patients who received early physical therapist management had increased odds of achieving MCID on the NDI (aOR = 2.01, 95 % CI 1.57, 2.56) and MCID on the NPRS (aOR = 1.82, 95 % CI 1.42, 2.38), when compared to patients receiving delayed management. Patients who received early management demonstrated the greatest value in decreasing disability with a 2.27 percentage point change in NDI score per 100 dollars, best value in decreasing pain with a 0.38 point change on the NPRS per 100 dollars. Finally, patients receiving early management were managed more efficiently with a 3.44 percentage point change in NDI score per visit and 0.57 point change in NPRS score per visit. CONCLUSIONS: These findings suggest that healthcare systems that provide pathways for patients to receive early physical therapist management of neck pain may realize improved patient outcomes, greater value and higher efficiency in decreasing disability and pain compared to delayed management. Further research is needed to confirm this assertion.

Association between malnutrition and Barthel Index in a cohort of hospitalized older adults article information.

[Purpose] In this study, we sought to evaluate the relationship between the Barthel Index and the Mini Nutritional Assessment Short Form in a cohort of elderly patients hospitalized in the General Rehabilitation Center. [Subjects and Methods] Three hundred and forty-four patients underwent an extensive evaluation, which included the following tests: 1) a Mini Nutritional Assessment Short Form to evaluate nutritional status; and 2) a Barthel Index assessment to evaluate functional status. We categorized patients into three age groups (65-74 yrs, 75-84 yrs, and >85 yrs). Barthel Index cutoff scores were defined as ≥45 out of 100 for better functional status and <45 for worse functional status. [Results] Significant associations between age distribution and the scores obtained with the Barthel Index and Mini Nutritional Assessment Short Form were found; nutritional status measured with Mini Nutritional Assessment Short Form and functional status measured with the Barthel Index were positively related. [Conclusion] This study shows that the Mini Nutritional Assessment Short Form value was associated with the Barthel Index score, and that these scores varied with age.

Description of Common Clinical Presentations and Associated Short-Term Physical Therapy Clinical Outcomes in Patients With Neck Pain.

OBJECTIVE: To determine the effect of clinical presentations of neck pain on short-term physical therapy outcomes. DESIGN: Retrospective analysis of pair-matched groups from a clinical cohort. SETTING: Thirteen outpatient physical therapy clinics in 1 health care system. PARTICIPANTS: Patients (N=1069) grouped by common clinical presentations of neck pain: nonspecific neck pain (NSNP) with duration <4 weeks; NSNP with duration >4 weeks; neck pain with arm pain; neck pain with headache; and neck pain from whiplash. INTERVENTION: Conservative interventions provided by physical therapists. MAIN OUTCOME MEASURES: Neck Disability Index (NDI) and numerical pain rating scale (NPRS) recorded at the initial and last visits. The main outcome of interest was achieving recovery status on the NDI. Changes in NDI and NPRS were compared between clinical presentation groups. RESULTS: Compared with patients presenting with NSNP >4 weeks, patients with NSNP <4 weeks had increased odds of achieving recovery status on the NDI (P<.0001) and demonstrated the greatest changes in clinical outcomes of pain (P≤.0001) and disability (P≤.0001). Patients with neck pain and arm pain demonstrated an increased odds of achieving recovery status on the NDI (P=.04) compared with patients presenting with NSNP >4 weeks. CONCLUSIONS: Treating patients with NSNP within <4 weeks of onset of symptoms may lead to improved clinical outcomes from physical therapy compared with other common clinical presentations.

Immediate changes after manual therapy in resting-state functional connectivity as measured by functional magnetic resonance imaging in participants with induced low back pain.

OBJECTIVE: The purposes of this study were to use functional magnetic resonance imaging to investigate the immediate changes in functional connectivity (FC) between brain regions that process and modulate the pain experience after 3 different types of manual therapies (MT) and to identify reductions in experimentally induced myalgia and changes in local and remote pressure pain sensitivity. METHODS: Twenty-four participants (17 men; mean age ± SD, 21.6 ± 4.2 years) who completed an exercise-injury protocol to induce low back pain were randomized into 3 groups: chiropractic spinal manipulation (n = 6), spinal mobilization (n = 8), or therapeutic touch (n = 10). The primary outcome was the immediate change in FC as measured on functional magnetic resonance imaging between the following brain regions: somatosensory cortex, secondary somatosensory cortex, thalamus, anterior and posterior cingulate cortices, anterior and poster insula, and periaqueductal gray. Secondary outcomes were immediate changes in pain intensity, measured with a 101-point numeric rating scale, and pain sensitivity, measured with a handheld dynamometer. Repeated-measures analysis of variance models and correlation analyses were conducted to examine treatment effects and the relationship between within-person changes across outcome measures. RESULTS: Changes in FC were found between several brain regions that were common to all 3 MT interventions. Treatment-dependent changes in FC were also observed between several brain regions. Improvement was seen in pain intensity after all interventions (P < .05) with no difference between groups (P > .05). There were no observed changes in pain sensitivity, or an association between primary and secondary outcome measures. CONCLUSION: These results suggest that MTs (chiropractic spinal manipulation, spinal mobilization, and therapeutic touch) have an immediate effect on the FC between brain regions involved in processing and modulating the pain experience. This suggests that neurophysiologic changes after MT may be an underlying mechanism of pain relief.

Pain and Disability Following Exercise-Induced Injury in Prognostic and Intervention Studies: The Why May Be More Important Than the How.

OBJECTIVES: In preclinical prognostic studies, the description of expected outcomes during an informed consent process indicates that the extent of pain and disability experienced and recovery time is unknown. In intervention studies, the consent process suggests that pain and disability will definitely occur and a treatment provided. Our objective was to determine whether study design (prognosis or intervention) was associated with the severity of pain intensity and disability reports from a preclinical model. MATERIALS AND METHODS: We pooled pain and disability outcomes from prognostic and intervention studies using an exercise-induced muscle injury model of pain. Pain intensity, disability, and fear of pain were collected by validated self-report measures. Pain and disability data were z-transformed for pooled analyses and compared across the study design. RESULTS: Data from 310 people were included. The primary findings were that self-reported pain intensity and disability were: (1) higher in prognostic studies than in the intervention studies and (2) associated with fear of pain. A secondary finding was that fear of pain was lower in the intervention compared with the prognostic studies. DISCUSSION: Although there are other possible explanations, we speculate that these results could be related to the uncertainty inherent to providing informed consent for a prognostic study. In light of these findings, we recommend that informed consent language be more carefully considered when pain is induced in a controlled manner. Incorporating informed consent language commonly used in prognostic studies could result in higher pain intensity and disability ratings in studies that use preclinical models to test the efficacy of pain interventions.

Pain and Dysfunction Reported After Gender-Affirming Surgery: A Scoping Review.

OBJECTIVE: The goal of this scoping review was to determine the types and rates of pain and dysfunction outcomes reported after gender-affirming surgical procedures. In addition, a summary of the involvement of conservative care reported in the literature was produced. METHODS: A research librarian conducted searches through multiple databases from inception to 2021. Abstracts and full texts were reviewed by a team of at least 2 reviewers. Data were extracted from a custom survey and exported for summary. RESULTS: Thirty-one papers discussed masculinizing interventions, and 87 papers discussed feminizing procedures. Most of the studies emphasized surgical outcomes. Of the studies reporting pain or dysfunction, few standardized outcomes were used to collect information from patients. The pain was experienced across body regions after surgery for both feminizing and masculinizing procedures. Vaginal stenosis and incontinence were the most common complications reported. Patients were most often managed by physical therapists for vaginal stenosis or dyspareunia. CONCLUSION: Many published studies do not systematically collect specific or standardized information about pain and dysfunction after gender-affirming surgery. Of those studies that do report these outcomes, few detail the involvement of physical therapists in the recovery after surgery. IMPACT: Pain and urogenital dysfunction, often managed by physical therapists, occur after gender-affirming surgery, suggesting that physical therapists could have a larger role in the recovery of this patient population after surgery. The extent to which interventions used to manage these conditions in cisgender people will be equally effective in transgender people is unknown at this time. Future studies should use recognized measures to characterize patients' experiences with pain and dysfunction after surgery.

Expectations affect pain sensitivity changes during massage.

BACKGROUND: Pain-inducing massage produces comparable changes in pain sensitivity as a cold pressor task, suggesting shared neurophysiological mechanisms of conditioned pain modulation. Manual therapy and conditioned pain modulation are influenced by positive and negative expectations. Therefore, the purpose of this study was to examine the effects of positive and negative expectations on pain-free and pain-inducing massage. METHODS: 56 healthy participants were randomly assigned to receive a positive or negative expectation instructional set followed by a pain-inducing or a pain-free massage. Pressure pain threshold (PPT) was measured followed by each interval of massage. A repeated measures ANCOVA controlling for post-randomization differences in sex tested for massage x expectation set x PPT interaction effects, as well as two-way interaction effects. RESULTS: A significant three-way interaction effect (p = 0.04) and time x expectation interaction effect was observed for individuals receiving pain inducing massage (p = 0.02). Individuals who received the positive expectation instructional set demonstrated significantly higher PPT at minutes 3 and 4 of massage compared to individuals who received the negative expectation instructional set. CONCLUSIONS: Expectations impact pain sensitivity changes produced during massage. Clinicians planning to provide pain-inducing massage should consider the role of expectations in modulating pain sensitivity changes.

Characteristics and Outcomes of Patients Receiving Physical Therapy for Low Back Pain with a Nociplastic Pain Presentation: A Secondary Analysis.

Introduction: Individuals with low back pain (LBP) may be classified based on mechanistic descriptors, such as a nociplastic pain presentation (NPP). The purpose of this secondary analysis was to examine the frequency and characteristics of patients with a NPP referred to physical therapy with LBP. Additionally, we characterized patients with LBP meeting the criteria for NPP by demographic, clinical, psychological, and pain sensitivity variables. Finally, we examined short- and long-term clinical outcomes in patients with a NPP compared to those without a NPP. Materials and Methods: Patients referred to physical therapy for LBP completed the Patient Self-report Survey for the Assessment of Fibromyalgia. Participants were categorized as "LBP with NPP" or "LBP without NPP" based on the threshold established in this measure. A rank sum test examined for differences in pain-related psychological factors and pressure-pain threshold between groups. Next, a Friedman test examined if LBP intensity and disability trajectories differed by groups at one and six months after initiation of physical therapy. Results: 22.2% of patients referred to physical therapy for LBP met the criteria for a NPP. Patients with a NPP reported significantly greater disability, pain catastrophizing, depression, anxiety, and somatization compared to individuals without a NPP (p < 0.05). Pressure-pain threshold did not differ between groups (p > 0.05). Individuals with LBP with a NPP demonstrated nonsignificant, small to medium reductions in pain and disability at one and six months. Individuals experiencing LBP without a NPP demonstrated significant reductions in pain and disability in the short- and long term. Conclusion: Patients with LBP with a NPP displayed greater negative pain-related psychological factors but similar pain sensitivity compared to LBP without NPP.

Biopsychosocial influence on shoulder pain: results from a randomized preclinical trial of exercise-induced muscle injury.

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.

Pain phenotyping and investigation of outcomes in physical therapy: An exploratory study in patients with low back pain.

Phenotypes have been proposed as a method of characterizing subgroups based on biopsychosocial factors to identify responders to analgesic treatments. This study aimed to, first, confirm phenotypes in patients with low back pain receiving physical therapy based on an a priori set of factors used to derive subgroups in other pain populations. Second, an exploratory analysis examined if phenotypes differentiated pain and disability outcomes at four weeks of physical therapy. Fifty-five participants completed psychological questionnaires and pressure pain threshold (PPT). Somatization, anxiety, and depression domains of the Symptom-Checklist-90-Revised, and PPT, were entered into a hierarchical agglomerative cluster analysis with Ward's method to identify phenotypes. Repeated measures ANOVAs assessed pain ratings and disability by phenotype at four weeks. Three clusters emerged: 1) high emotional distress and pain sensitivity (n = 10), 2) low emotional distress (n = 34), 3) low pain sensitivity (n = 11). As an exploratory study, clusters did not differentiate pain ratings or disability after four weeks of physical therapy (p's>0.05). However, trends were observed as magnitude of change for pain varied by phenotype. This supports the characterization of homogenous subgroups based on a protocol conducted in the clinical setting with varying effect sizes noted by phenotype for short-term changes in pain. As an exploratory study, future studies should aim to repeat this trial in a larger sample of patients.

Circulating Inflammatory Biomarkers Predict Pain Change Following Exercise-Induced Shoulder Injury: Findings From the Biopsychosocial Influence on Shoulder Pain Preclinical Trial.

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; ߈ = .62; 95% confidence interval [CI] = -.03, 1.26), interleukin-6 (IL-6; ߈ = 3.13; CI = -.11, 6.38), and interleukin-10 (IL-10; ߈ = 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 (߈ = -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.

Radial nerve mobilization decreases pain sensitivity and improves motor performance in patients with thumb carpometacarpal osteoarthritis: a randomized controlled trial.

OBJECTIVE: To examine the effects of radial nerve mobilization on pain sensitivity and motor performance in subjects with secondary thumb carpometacarpal osteoarthritis. DESIGN: Randomized controlled trial. Treatment and placebo were given for 4 weeks. Measurements were taken before intervention, after 1 month (first follow-up), and after 2 months (second follow-up). SETTING: Patients from the Department of Physical Therapy, Azienda Sanitaria Locale 3, Collegno (Italy). PARTICIPANTS: Participants (N=60; age range, 70-90y) with right-dominant hand secondary thumb carpometacarpal osteoarthritis without other motor-related pathology. All patients completed the study. No patients were withdrawn from the study. INTERVENTIONS: Sliding mobilization of the proximal-distal radial nerve or intermittent ultrasound therapy, used as placebo. MAIN OUTCOME MEASURES: We hypothesized that radial nerve mobilization induces hypoalgesia and increases strength in secondary thumb carpometacarpal osteoarthritis. We measured pressure pain threshold (PPT) at the trapeziometacarpal joint, the tubercle of the scaphoid bone, and the unciform apophysis of the hamate bone by algometry. Tip pinch strength and tripod pinch strength were measured by a mechanical pinch gauge. RESULTS: Treatment increased PPT by 3.33±.24 kg/cm(2) (P<.001) in the trapeziometacarpal joint and was maintained until first follow-up and second follow-up. Also, PPT in the scaphoid bone and hamate bone was increased (P<.001 and P<.02, respectively). Variables in the placebo group remained unchanged. Tip pinch strength increased by 2.22±.22 kg (P<.04) and tripod pinch strength by 2.83±.24 kg (P<.019). CONCLUSIONS: Radial nerve mobilization decreases pain sensitivity in the trapeziometacarpal joint and increases tip pinch strength.