Widespread Mechanical Pain Hypersensitivity as Sign of Central Sensitization in Unilateral Epicondylalgia: A Blinded, Controlled Study

When Lateral Epicondylitis Is Not Lateral Epicondylitis: Analysis of the Risk Factors for the Misdiagnosis of Lateral Elbow Pain

BACKGROUND

Lateral elbow pain, often attributed to lateral epicondylitis, presents diagnostic complexities. Lateral epicondylitis, or tennis elbow, is the most frequent cause of lateral elbow pain, but a differential diagnosis among all the potential causes of lateral elbow pain is not easy.

PURPOSE

To evaluate the rate of misdiagnoses in patients previously diagnosed with lateral epicondylitis, identify at-risk patient profiles, and determine sensitive clinical tests for a misdiagnosis.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A prospective analysis was conducted on 189 consecutive patients with a previous diagnosis of lateral epicondylitis and failed nonoperative treatment. According to medical history and a physical examination, patients were preliminarily classified into the typical or atypical lateral epicondylitis group. Atypical epicondylitis was defined as one of the following: atypical lateral pain location, history of trauma, limited range of motion (ROM), elbow swelling, negative Cozen test finding, and physical examination findings suggesting a misdiagnosis. Patients in the atypical group were further investigated for a potential lateral epicondylitis misdiagnosis using magnetic resonance imaging, computed tomography, and/or analysis of intraoperative samples according to suspected underlying abnormalities. Univariate and logistic regression analyses were conducted to assess the risk of a misdiagnosis. A standardized diagnostic analysis was performed to evaluate the clinical tests used during the physical examination to identify misdiagnosed patients.

RESULTS

A misdiagnosis occurred in 21 of 189 (11%) patients. The most common misdiagnoses were posterolateral elbow instability in 6 patients; radial nerve compression and inflammatory osteoarthritis in 3 patients each; and osteochondritis dissecans, posterolateral plica, and primary osteoarthritis in 2 patients each. The variables associated with a misdiagnosis were young age (≤30 years; odds ratio [OR], 66.90; P < .001), history of trauma (OR, 17.85; P = .0027), history of a limitation of ROM and/or mechanical symptoms (OR, 16.68; P = .0278), history of elbow swelling (OR, 14.32; P = .0032), and number of corticosteroid injections (OR, 2.00; P = .0007). Atypical lateral pain location highly predicted a misdiagnosis, with a sensitivity of 90.5%.

CONCLUSION

A misdiagnosis can occur in patients affected by longstanding lateral elbow pain. Young patients and patients with a history of elbow trauma, a limitation of ROM, swelling, corticosteroid injections, and atypical lateral pain should be highly suspected for a misdiagnosis.

The Effects of Noxious Electrical Stimulation and Eccentric Exercise on Mechanical and Thermal Pain Sensitivity in Recreational Runners with Achilles Tendinopathy

Background

Achilles tendinopathy is a common overuse condition that can become persistent despite conservative treatment. Sensitization of both the peripheral and central nervous systems may contribute to the persistent pain. Both exercise and electrical stimulation have the potential to modulate the nervous system's sensitivity to painful stimuli.

Hypothesis/Purpose

The purpose of this study was to describe the changes in pain sensitivity and self-reported function in runners with chronic Achilles tendon pain following sequential treatment with noxious electrical stimulation (NxES) and eccentric plantarflexion exercise.

Study Design

Single group, repeated measures design.

Methods

Sixteen participants with chronic Achilles tendinopathy completed the Lower Extremity Functional Scale (LEFS) and the Victorian Institute of Sport Assessment-Achilles scale (VISA-A) and quantitative sensory tests (pressure pain threshold, heat temporal summation, and heat pain threshold) at baseline, one week, seven weeks, and then at a one month post intervention follow-up. The NxES was applied for one week, then followed by plantarflexion eccentric exercise for six weeks. Changes across timepoints were assessed using repeated measures ANOVA and post hoc analysis to describe differences. Hedges g effect sizes were also calculated.

Results

There was a significant improvement in LEFS (p < 0.001) and VISA-A (p < 0.001) from baseline to one month follow-up, with a mean change of 9.6 ± 7.7 and 19.4 ± 17.7 points respectively. Pressure pain threshold of the involved Achilles tendon increased over time (p < 0.001) with significant improvements after NxES application (p = 0.002) and after six weeks of eccentric exercise (p < 0.001). There were significant improvements from baseline to one month follow-up for heat temporal summation (p = 0.001) and heat pain threshold ( p < 0.001).

Conclusions

For individuals with chronic Achilles tendinopathy, a sequential treatment of NxES followed by eccentric exercise resulted in a clinically significant improvement in self-reported pain and function. During the first week of treatment there was a reduction in mechanical hyperalgesia during the NxES-only phase, while a large reduction in primary heat hyperalgesia and additional desensitization to mechanical pain occurred during the eccentric training phase of treatment.

Level of Evidence

2b.

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

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

Excitation of the bottom-up pathways has no effect on remote muscle fatigue in healthy participants

The aim of this study is to investigate the effect of induced excitation of the bottom-up pathways at the lateral elbow muscles on local muscle fatigue in the neck region in healthy participants. Eligible participants (n:55) were randomly allocated to an intervention group (n:28) or a control group (n:27). The fatigue of bilateral neck flexor(sternocleidomastoid) and extensor (upper trapezius) muscles was evaluated using surface electromyography, at baseline and immediately post-intervention during a neck flexor and extensor endurance test respectively. Excitation of the bottom-up pathways was performed at multiple lateral elbow muscles in the intervention group by using a temporal summation protocol of mechanical pain, and the pressure pain threshold was determined once in each of the multiple lateral elbow muscles in the control group. Linear mixed model analyses were performed for each outcome measure to evaluate changes over time and within- and between-group differences. No significant "group X time" interaction effects were detected for any of the outcome measures. Significant main effects for time was found for "amplitude over time" of the left upper trapezius (p:0.003) and right sternocleidomastoid muscle (p: 0.013), and for "amplitude changes" of the left upper trapezius muscle (p:0.021). Significant within-group changes were identified in some outcomes in the control group: increased "amplitude over time" of the right sternocleidomastoid muscle (p:0.024) and decreased "amplitude changes" of the left upper trapezius muscle (p:0.024), decreased "normalized median frequency slope over time" of the left UT (p: 0.013). There were no significant within-group changes in the intervention group. No significant between-group differences for any of the outcome measures were found. This study shows no effect of the induction of excitation of the bottom-up pathways at the lateral elbow muscles on the neck muscles' fatigue characteristics compared to a control intervention. Clinical Trial Number: NCT05146960. Date of Registration: December 7, 2021.

Analysis and relationship between the volume of upper limb lymphoedema and pressure pain threshold, neural range of motion, pain intensity, kinesiophobia, pain hypervigilance and catastrophizing in breast cancer survivors

BACKGROUND

Lymphedema of the upper limbs and persistent pain are frequent sequelae after surgical treatment of breast cancer.

AIM

The aim of this paper was to analyze the upper limb volume, pressure pain threshold, neural range of motion, pain intensity, kinesiophobia, pain hypervigilance and catastrophizing in patients with and without lymphoedema after breast cancer surgery. Secondly, we aimed to investigated the association between upper limb volume and these variables.

DESIGN

Descriptive observational study.

SETTING

Faculty of Health Sciences of the University of Granada.

POPULATION

Fifty-eight post-surgical breast cancer survivors, 29 with upper limb lymphoedema and 29 without lymphoedema.

METHODS

We measured upper limb volume (perimetric method). Also, pressure pain thresholds were assessed with a digital algometer, neural range of motion (neurodynamic test for radial, ulnar and median nerves), pain intensity (visual analogue scale), kinesiophobia, pain hypervigilance and catastrophizing (validated tests). To detect differences between the groups for the measurement variables we performed a t-test for independent samples analysis. A simple linear regression analysis adjusting for age and body mass index was performed to check the association among upper limb volume and pain variables in the group with lymphoedema.

RESULTS

The analysis showed that lymphoedema group had lower pressure pain threshold bilaterally in the masseter (origin P≤0.036; insertion P≤0.046), temporalis (insertion P≤0.021), suboccipitalis (P≤0.036); second (P≤0.014), third (P≤0.001) and tenth rib (P≤0.001); affected side of the temporalis (origin P=0.025); temporomandibular joint (P=0.024); neural range of motion in the median nerve (P=0.047), ulnar (P=0.042) on the affected side and radial (P=0.039) on the unaffected side; and greater kinesiophobia (P=0.042). Linear regression analysis only showed a significant association between upper limb volume and neural range of motion in the radial nerve (P=0.020) in the lymphedema group. No significant associations were obtained for the rest of variables.

CONCLUSIONS

These findings suggest that the presence of lymphoedema may contribute to an increased level of generalized mechanosensitivity and fear to movement in this population.

CLINICAL REHABILITATION IMPACT

Upper limb lymphedema can lead to heightened mechanosensitivity and movement-related fear in breast cancer survivors. Therefore, fast track rehabilitation approach should be focus in screening and rehabilitation methods for detection and control this sequalae.

The critical importance of recognition, evaluation, and management of mental health on outcomes following hip arthroscopy - A synthetic narrative review: Current concepts

Mental health and wellness influence patients with hip pain and dysfunction secondary to Femoroacetabular Impingement Syndrome, acetabular dysplasia, and labral injury. Disorders of mental wellness may impact hip preservation surgery patients both before and after surgery. Major depression and generalized anxiety are the two most common diagnoses that affect hip preservation surgery patients. There are dozens of unique questionnaires that can subjectively and objectively characterize the mental health of patients with hip pain. Pain threshold and pain tolerance are two issues that must be recognized to optimally predict treatment outcome in an informed consent shared decision-making discussion. Patient expectations may also significantly influence preoperative symptoms and postoperative outcome. Pain threshold, pain tolerance, and patient expectations are entities traditionally viewed as qualitative and unmeasurable. However, many valid and reliable methods exist to quantitatively assess these patient-specific variables. Recent original research and synthetic review publications have consistently concluded similar findings: patients with disorders of mental wellness generally have lower preoperative patient-reported outcome scores, do improve following surgery, albeit to a lesser magnitude than non-mental disorder patients, and ultimately have lower postoperative scores at their final follow. As with most orthopaedic surgery literature, the investigation of mental health and hip preservation is primarily via retrospective level four evidence with small numbers of patients from a single centre and single surgeon at short-term follow-up. Although hip preservation surgeons are orthopaedic surgeons by training and practice, they must be able to recognize mental wellness disorders and either treat or refer when suspected or identified.

Immersive VR movement visualization in patients with hemophilic knee arthropathy: randomized, multicenter, single-blind clinical trial

PURPOSE

To evaluate the efficacy of an immersive movement visualization intervention in patients with hemophilia and hemophilic knee arthropathy.

MATERIALS AND METHODS

Randomized, single-blind clinical study. Twenty-eight patients with hemophilia were recruited. Patients were randomized to an experimental group (four weeks of immersive movement visualization) and a control group (no intervention). The intensity of pain, pressure pain threshold in the knee, tibialis anterior muscle, lower back level, conditioned pain modulation, range of knee motion, and lower limb functionality were evaluated.

RESULTS

There were statistically significant differences in the intergroup effect on knee pain intensity (F = 23.71; p < 0.001) and lower limb functionality (F = 7.11; p = 0.003). 42.86% of the patients in the experimental group exhibited changes greater than the minimum detectable change (MDC) in functionality. 39.29% of the patients subject to the intervention experienced changes greater than the MDC in the knee pressure pain threshold.

CONCLUSIONS

Immersive motion visualization can improve the intensity of joint pain and functionality in patients with hemophilic knee arthropathy. Functionality, pressure pain threshold, and pain intensity improved in those patients who conducted immersive movement visualization.Implications for rehabilitationImmersive visualization of movement significantly improves intensity of joint pain, functionality, pressure pain threshold, joint health, and conditioned pain modulation in patients with hemophilic knee arthropathy.The fact that it is a therapy without potential aversive stimuli makes it a possible access pathway for patients with high levels of kinesiophobia and/or catastrophism.This low-cost, home-based technology allows its use in patients far from hemophilia reference centers or with difficult access to physiotherapy treatments.The immersive visualization of movement influences the democratization of treatment, in accordance with the WHO's Sustainable Development Goal 3 (health and well-being for all).

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

INTRODUCTION

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

METHOD

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

RESULTS

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

CONCLUSION

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

The usage of a modified straight-leg raise neurodynamic test and hamstring flexibility for diagnosis of non-specific low back pain: A cross-sectional study

OBJECTIVES

The main purpose of this research study was to compare mean modified straight-leg raise test (mSLR) and hamstring muscle length (HL) between chronic non-specific low back pain (LBP) and healthy subjects to understand the possibility of neuropathic causes in LBP population as it may impact the diagnosis and treatment of LBP. Another purpose was to compare mean mSLR between those with lumbar nerve root impingement and those without as determine by magnetic resonance imaging (MRI).

METHODS

The design of the study is cross sectional and included 32 subjects with ages ranging from 18-50 years old. Clinical exam objective measures were collected such as patient questionnaires, somatosensory tests, HL range of motion, and a mSLR test, and were compared to the findings from a structural lumbar spine MRI.

RESULTS

There were no significant differences in mean HL angulation and mSLR angulation between LBP and healthy subjects (p>0.05). There was no significant difference in mean HL by impingement by versus no impingement (38.3±15.6 versus 44.8±9.4, p = 0.08, Cohen's d = 0.50). On the other hand, there was a significant difference in mean mSLR angulation by impingement (57.6.3±8.7 versus 63.8±11.6, p = 0.05, Cohen's d = 0.60).

CONCLUSIONS

The mSLR test was found to be associated with lumbar nerve root compression, regardless of the existence of radiating leg symptoms, and showed no association solely with the report of LBP. The findings highlight the diagnostic dilemma facing clinicians in patients with chronic nonspecific LBP with uncorrelated neuroanatomical image findings. Clinically, it may be necessary to reevaluate the common practice of exclusively using the mSLR test for patients with leg symptoms. This study may impact the way chronic LBP and neuropathic symptoms are diagnosed, potentially improving treatment methods, reducing persistent symptoms, and ultimately improving disabling effects.

Botulinum Toxin in Chronic Lateral Epicondylitis, from Tendon to Muscle Approach-A Review

BACKGROUND

Chronic lateral epicondylitis challenges the therapeutical approach; underlying mechanisms are incompletely understood; neuropathic pain and central and peripheral sensitization may explain the fact that botulinum toxin has been found to play a role in pain and function management.

METHODS

We searched the literature for MeSH terms: lateral epicondylitis or synonyms and botulinum toxin.

RESULTS

We found 14 papers containing trials on botulinum toxin injection into the tendon or into the extensor muscles (specifically, extensor carpi radialis brevis and extensor communis digitorum). We followed the administration pathways, doses, timing, and side effects.

CONCLUSIONS

With a chronic course, the focus of the therapy shifts from the afflicted tendon to the inserting muscles, as muscle contracture may create a vicious loop to perpetuate and aggravate the disease. Doses, timing, and side effects are discussed.

Assessment of Prevalence and Risk Factors for Central Sensitization Related to Shoulder Osteoarthritis and Rotator Cuff Tears Using the Central Sensitization Inventory: A Cross-Sectional Study in Shoulder Surgery Patients

Shoulder disorders occasionally cause intractable pain. Central sensitization (CS) may be involved in such pain. Identifying risk factors associated with CS is crucial for effective pain control. This study aimed to determine the effects of shoulder osteoarthritis and rotator cuff tears (RCT) on CS and associated factors. This study included patients evaluated for CS using the Central Sensitization Inventory (CSI) before surgery for shoulder osteoarthritis, RCT, or cuff tear arthropathy. Patients with a CSI score of 40 or higher were defined as having CS. The relationships between glenohumeral osteoarthritis (GHOA), RCT size, and CS were statistically analyzed. Multiple regression analysis was performed to examine the factors affecting CSI scores. Subjects included 167 patients: 131 patients had RCT without GHOA, 23 had GHOA with RCT, and 13 had GHOA without RCT. The GHOA group had a significantly higher CSI score (27.5 [10.8-40.5] vs. 18.0 [10.0-27.5]) and CS prevalence (27.8% vs. 8.4%) than the RCT without GHOA group. There was no significant correlation between RCT size and CSI scores. Multiple regression analysis showed that female sex, severe pain, and long pain duration were associated with higher CSI scores. Considering the risk factors for CS might be helpful in shoulder treatment.

A Pilot Test of the Measures of the Greek Version of Upper Extremity Functional Index in Patients with Lateral Elbow Tendinopathy

Lateral elbow tendinopathy (LET) is a common upper limb pathology in people involved in manual occupations. The upper extremity functional index (UEFI) was specifically designed to evaluate functional limitations in patients with upper limb pathology. The UEFI was developed in English and has been translated into several languages, including Greek. However, it has been assessed only in patients with shoulder pathology. Thus, the aim of this study was to pilot-test the Greek version of the UEFI (GV-UEFI) questionnaire and assess its measurement properties in patients with LET. Thirty patients with LET were recruited and asked to fill in the GV-UEFI twice and the disabilities of arm, shoulder, and hand questionnaire (DASH) once. The internal consistency and test-retest reliability were examined using Cronbach's alpha and the intraclass correlation coefficient (ICC). The standard error of measurement (SEM) and the minimum detectable change (MDC) were calculated and possible ground or ceiling effects were also examined. Convergent validity was evaluated with the Greek DASH using Pearson's correlation. Lastly, the unidimensionality of the scale was examined through principal component analysis to verify construct validity. Internal consistency was high for the GV-UEFI (Cronbach's a = 0.98) and test-retest reliability was excellent (ICC = 0.98). The SEM was 2.95 and the MDC was 6.85. Test-retest reliability of each item was good (ICC > 0.87). The correlation analysis demonstrated a strong correlation between the GV-UEFI and the DASH. No floor or ceiling effects were found. Principal component analysis verified the construct validity and the unidimensionality of the scale. The GV-UEFI was successfully tested in patients with LET. It seems that the GV-UEFI can be used reliably in Greek-speaking patients with LET. However, the measurement properties of this scale should be examined in a larger sample of LET patients.

Wrist Extensor Training With Blood Flow Restriction for the Management of Lateral Elbow Tendinopathy: A Case Report

Lateral elbow tendinopathy (LET) is a common overuse injury with complex underlying pathophysiological mechanisms. Although several modes of exercise with or without passive interventions have been recommended as the first-line treatment option of the condition, their effectiveness remains inconclusive. The aim of this case report is to evaluate the effect of wrist extensor exercises with blood flow restriction (BFR) as an add-on intervention to a multi-modal physiotherapy programme to improve outcomes in a patient with LET. A 51-year-old male patient presented with a history of right LET for six months. Interventions included wrist extension exercise with BFR, a two-stage progressive loading training programme of the upper limb, soft-tissue massage, education and a home exercise programme for six weeks (12 visits). A substantial improvement in pain intensity, pain-free grip strength, Patient Rated Tennis Elbow Evaluation score and self-perceived recovery was reported at three-, six-, and 12-week follow-up measurements. A 21% reduction in pressure pain thresholds at the lateral epicondyle was found immediately after wrist extensor exercise with BFR. Based on our findings, adding wrist extensor exercises with BFR to a multimodal physiotherapy programme seems a promising approach to improve the treatment outcome in LET. Nonetheless, further research is needed to confirm the present results.

Myofascial Trigger Points and Central Sensitization Signs, but No Anxiety, Are Shown in Women with Dysmenorrhea: A Case-Control Study

Background primary dysmenorrhea (PD) is considered to be a cyclic chronic pelvic pain, with its onset in menstrual periods, often accompanied by the presence of myofascial trigger points (MTP). Most MTPs in subjects with chronic pelvic pain are in the inferior part of the abdomen, in the rectus abdominis (RA) area. Central sensitization is closely related to chronic pain processes. Previous studies in women with chronic pelvic pain reported central sensitization signs in their subjects, such as lower pain pressure threshold (PPT). Several authors agree that PPT in the tibialis anterior (TA) muscle, seems to be a reliable reference for signs of central sensitization. Amongst the factors that seem to accompany central sensitization, the presence of anxiety needs to be considered. The aim of the present study was to analyze the existence of hyperalgesic MTPs in RA, central sensitization signs and anxiety in women with PD, in comparison with a control group (CG). Methods: This study was designed following an observational, cross-sectional, case-control model. A total sample of 80 subjects was recruited trough social webs and advertising (PD n = 39) (CG n = 41). PPT in RA and AT was assessed bilaterally through algometry, and anxiety was evaluated through the State−Trait Anxiety Inventory. Results: Statistically significant differences (p < 0.001) were shown for NRS average and maximum increase, as well as lower bilaterally RA and TA PPT in favor of PD group compared to CG. State or trait STAI did not show any statistically significant differences (p > 0.05) between groups. Conclusions: In this study, women with PD reported symptoms of myofascial pain syndrome and central sensitization, when compared with healthy controls, without any sign of anxiety acting as a confounder for pain sensitivity.

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

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

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

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

Treatment, Diagnostic Criteria and Variability of Terminology for Lateral Elbow Pain: Findings from an Overview of Systematic Reviews

Background: Lateral elbow pain (LEP) represents a musculoskeletal disorder affecting the epicondyloid region of the elbow. The terminological framework of this problem in literature, to date, is confusing. This systematic review (SR) aims to analyse the panorama of the scientific literature concerning the pathogenetic framework, treatment, and clinical diagnosis of LEP. Methods: We conducted an SR according to the guidelines of the PRISMA statement. We performed research using the electronic Medline, Epistemonikos, and Cochrane Library databases. The research started on 12 January 2022 and finished on 30 April 2022. We included all systematic reviews and meta-analyses published, in English, between 1989 and 2022. The articles’ selection was based on critical appraisal using Amstar 2. In the selected reviews we obtained the etiopathogenic terminology used to describe the symptoms, treatment, and diagnostic criteria of LEP. Results: Twenty-five SRs met the eligibility criteria and were included in the study. From these SRs, 227 RCT articles were analysed and different treatments proposals were extracted, such as exercise, manipulation corticosteroid injection, and surgery. In the selected articles, 10 different terms emerged to describe LEP and 12 different clinical tests. The most common treatments detected in this SR were a conservative multimodal approach (e.g., eccentric exercises, manual therapy, acupuncture, ultrasound), then surgery or other invasive treatments (e.g., corticosteroid injection, tenotomy). The most common term detected in this SR was “lateral epicondylitis” (n = 95, 51.6%), followed by “tennis elbow” (n = 51, 28.1%) and “lateral epicondylalgia” (n = 18, 9.4%). Among the diagnostic tests were painful palpation (n = 101, 46.8%), the Cozen test (n = 91, 42.1%), the pain-free grip-strength test (n = 41, 19.0%), and the Maudsley test (n = 48, 22.2%). A total of 43.1% of RCTs (n = 96) included subjects with LEP > 3 months, 40.2% (n = 85) included patients with LEP < 3 months, and 16.7% of the items (n = 35) were not specified by the inclusion criteria on the onset of symptoms. Conclusions: In this SR, a considerable terminological heterogeneity emerged in the description of LEP, associated with the lack of clear and recognised diagnostic criteria in evaluating and treating patients with lateral elbow pain.

Investigating the effects of neuromobilization in lateral epicondylitis

STUDY DESIGN

Randomized controlled study.

INTRODUCTION

Lateral epicondylitis (LE) causes pain and loss of function in the affected limb. Different exercises have been used for the treatment of LE. In recent years, the technique of neuromobilization has been frequently used to treat tendinopathy. However, there is no study that demonstrates the effects of neuromobilization techniques on patients with LE.

PURPOSE OF THE STUDY

The aim of the present study was to determine the effects of neuromobilization techniques on pain, grip strength, and functional status in LE patients and to compare them with conservative rehabilitation treatment.

METHODS

A total of 40 patients (26 females and 14 males; age: 42.80 ± 8.91 years) with a history of LE participated in the study. The patients were randomly assigned to two groups: the neuromobilization group and the control group. The neuromobilization group completed a 6-week conservative rehabilitation and radial nerve mobilization program, whereas the control group received conservative rehabilitation therapy only. Both groups underwent a 7-day weekly conservative home rehabilitation program. Pain severity, grip strength, pinch strength, joint motions, and upper extremity functional level were assessed before treatment, at the third week after treatment, and at the sixth week after treatment.

RESULTS

There was a significant decrease in all pain scores in favor of the neuromobilization group at week 6 after treatment (at rest: P = .001, effect size (ES) = 0.84; at night: P = .001, ES = 0.91 and during activity: P = .004, ES = 1.06). No significant differences were found for grip strength, pinch strength, joint motions, and functional level in the neuromobilization group, although trends toward better improvement were observed.

CONCLUSIONS

Radial nerve mobilization techniques are more effective on pain than conservative rehabilitation therapy in LE patients, and this effect continues after treatment.

Time Course and Risk Profile of Work-Related Neck Disability: A Longitudinal Latent Class Growth Analysis

OBJECTIVE

Given the economic burden of work-related neck pain and disability, it is important to understand its time course and associated risk factors to direct better management strategies. This study aimed to identify the 1-year trajectories of work-related neck disability in a high-risk occupation group such as sonography and to investigate which baseline biopsychosocial factors are associated with the identified trajectories.

METHODS

A longitudinal study was conducted among 92 sonographers with neck disability assessed at 3 time points-baseline, 6 months, and 12 months-using the Neck Disability Index. Baseline biopsychosocial measures included individual characteristics (demographics and physical activity levels), work-related physical and psychosocial factors (eg, ergonomic risk, workplace social support, job satisfaction), general psychological features (depression, anxiety, pain catastrophizing, and fear-avoidance beliefs), and quantitative sensory testing of somatosensory function (cold and pressure pain thresholds at neck and tibialis anterior, and temporal summation).

RESULTS

Two distinct trajectories of neck disability were identified, including a "low-resolving disability" trajectory showing slow improvement toward no disability (64.8%) and a "moderate-fluctuating disability" trajectory characterized by persistent moderate disability with a small fluctuation across time (35.2%). The trajectory of moderate-fluctuating disability was associated with more severe symptoms, lower vigorous physical activity, higher ergonomic risk, remote cold hyperalgesia, widespread mechanical hyperalgesia, heightened pain facilitation, and several psychosocial factors such as anxiety, depression, lower job satisfaction, and lower workplace social support at baseline.

CONCLUSION

Over one-third of sonographers were at risk of developing a moderate-fluctuating disability trajectory. This unfavorable trajectory was associated with low physical activity level, poor ergonomics, psychosocial distress, and central sensitization at baseline.

IMPACT

This study has important implications for the management of neck disability in workers. Addressing modifiable factors including low vigorous physical activity, poor ergonomics, anxiety, depression, and lack of workplace social support may improve the trajectory of work-related neck disability.

Use of the painDETECT to discriminate musculoskeletal pain phenotypes

Background

Musculoskeletal pain patients present similar pain characteristics regardless of the clinical diagnosis. PainDETECT questionnaire is useful for screening neuropathic-like symptoms in many musculoskeletal conditions. However, no previous studies compared pain phenotypes of patients with musculoskeletal pain using the painDETECT. Therefore, the current study aimed to compare the pain characteristics of patients with musculoskeletal pain classified according to the painDETECT as nociceptive pain, unclear, and neuropathic-like symptoms.

Methods

A cross-sectional study was conducted in 308 participants with musculoskeletal pain. Demographic and clinical characteristics of the participants were examined. Neuropathic-like symptoms, pain intensity, pain area, Central Sensitization-related sign and symptoms, functional limitation, and conditioned pain modulation were assessed in patients with musculoskeletal pain. Independent one-way analysis of variance (ANOVA) was used to test for between-group differences for the outcome measures with continuous variables and Pearson chi-square test verified between-group differences on the efficiency of the conditioned pain modulation.

Results

Participants had a mean age of 52.21 (±15.01) years old and 220 (71.42%) were females. One hundred seventy-three (56.16%) participants present nociceptive pain, 69 (22.40%) unclear, and 66 (21.42%) neuropathic-like symptoms. A one-way ANOVA showed differences for the pain intensity [F (2,305) = 20.097; p < .001], pain area [F (2,305) = 28.525; p < .001], Central Sensitization-related sign and symptoms [F (2,305) = 54.186; p < .001], and functional limitation [F (2,256) = 8.061; p < .001]. However, conditioned pain modulation was similarly impaired among the three groups (X² = 0.333, p = 0.847).

Conclusion

Patients with neuropathic-like symptoms revealed unfavorable pain characteristics compared to their counterparts, including pain intensity, generalized pain, Central Sensitization-related sign and symptoms, and functional limitation.

Can Central Sensitization after injury persist as an autonomous pain generator? - A comprehensive search for evidence

OBJECTIVE

To conduct a comprehensive search for evidence whether Central Sensitization following an injury can act as a persistent autonomous pain generator after the inducing injury has healed.

METHODS

We searched Medline on PubMed and the Cochrane Library, screening 3,572 abstracts, from which 937 full text articles were obtained, with 186 of these discarded as irrelevant to the question being posed. The remaining 751 articles were studied for evidence.

RESULTS

Fourteen publications were judged to provide weak evidence for the hypothesis of central sensitization as a persisting autonomous pain generator, but none addressed the question directly. No strong evidence for the affirmative answer was found.Sixty-two publications were judged to provide weak evidence for a negative answer, and nine judged to provide strong evidence.Unexpectedly, serious weaknesses were discovered in the literature underpinning the validity of the clinical diagnosis of Central Sensitization in man:(i)  Inappropriate extrapolation, in many publications, of laboratory animal data to humans.(ii) Failure to demonstrate the absence of peripheral pain generators which might be perpetuating Central Sensitization.(iii) Many factors now shown to confound what is being measured by quantitative sensory testing, conditioned pain modulation, and Central Sensitization Inventory.

CONCLUSIONS

We found no evidence proving that central sensitization can persist as an autonomous pain generator after the initiating injury has healed.Our review has also shown that the evidential basis for the diagnosis of CS in individual patients is seriously in question.

Joint position sense, motor imagery and tactile acuity in lateral elbow tendinopathy: A cross-sectional study

BACKGROUND

Impairments of sensorimotor function are evident in individuals with lateral elbow tendinopathy (LET), although understanding of the mechanisms for this is lacking.

OBJECTIVES

To determine if motor imagery, tactile acuity and wrist joint position sense (JPS) are impaired in participants with unilateral LET compared to controls, whether deficits are localised to the affected side, and whether deficits relate to severity of pain.

DESIGN

Cross-sectional study with control group.

METHODS

14 participants with unilateral LET of 6 weeks or longer and 14 matched control participants were assessed bilaterally for motor imagery (left/right hand judgement task), tactile acuity (two-point discrimination test) and wrist JPS (reposition test for flexion and extension). Pain levels were measured using a numeric rating scale.

RESULTS

Significant differences in JPS were observed for wrist extension only, such that participants with LET adopted less extended postures with their affected side when compared to their unaffected side (MD = 2.97°; p = 0.01) and to the matched-affected side of controls (MD = 4.89°; p < 0.01). No differences in tactile acuity or motor imagery were observed.

CONCLUSION

Altered wrist extension JPS, but not motor imagery or tactile acuity, was found in the affected side of patients with unilateral LET when compared to non-injured side and asymptomatic controls.

Evidence of Bilateral Localized, but Not Widespread, Pressure Pain Hypersensitivity in Patients With Upper Extremity Tendinopathy/Overuse Injury: A Systematic Review and Meta-Analysis

OBJECTIVE

The presence of altered nociceptive pain processing in patients with upper extremity tendinopathy/overuse injury is conflicting. Our aim was to compare pressure pain thresholds (PPTs) in symptomatic and distant pain-free areas between patients with upper extremity tendinopathy/overuse injury and controls.

METHODS

Five databases were searched from inception to October 15, 2020. The authors selected case-control studies comparing PPTs between individuals with upper extremity tendinopathy/overuse injury and pain-free controls. Data were extracted for population, diagnosis, sample size, outcome, and type of algometer. Results were extracted by 3 reviewers. The methodological quality/risk of bias (Newcastle-Ottawa Quality Assessment Scale) and evidence level (Grading of Recommendations Assessment, Development and Evaluation approach) were assessed. Meta-analyses of symptomatic, segment-related, and distant pain-free areas were compared.

RESULTS

The search identified 807 publications with 19 studies (6 shoulder, 13 elbow) eligible for inclusion. The methodological quality ranged from fair (48%) to good (37%). Patients exhibited lower bilateral PPTs than controls at the symptomatic area (affected side: MD = -175.89 kPa [95% CI = -220.30 to -131.48 kPa]; nonaffected side: MD = -104.50 kPa [95% CI = -142.72 to -66.28 kPa]) and the segment-related area (affected side: MD = -150.63 kPa [95% CI = -212.05 to -89.21 kPa]; nonaffected side: MD = -170.34 kPa [95% CI = - 248.43 to -92.25]) than controls. No significant differences in PPTs over distant pain-free areas were observed.

CONCLUSION

Low to moderate quality evidence suggests bilateral hypersensitivity to pressure pain at the symptomatic and contralateral/mirror areas in patients with upper extremity tendinopathies/overuse injury. Moderate quality of evidence supports bilateral pressure pain sensitivity in the segment-related area (neck) in lateral epicondylalgia, but not in subacromial impingement syndrome. No evidence of widespread pressure pain hyperalgesia was reported.

IMPACT

Early identification of people with altered pain modulation could guide clinicians in treatment strategies. This review shows that there is a complex interplay between peripheral and central pain mechanisms in upper extremity tendinopathies/overuse injuries and that there likely are different subgroups of patients with upper extremity conditions.

Heightened pain facilitation rather than impaired pain inhibition distinguishes those with moderate/severe disability in work-related neck pain

ABSTRACT

To better understand the mechanisms underpinning work-related neck pain, this cross-sectional and single-blinded study compared somatosensory profiles among sonographers with varied neck disability levels. Based on K-mean cluster analysis of scores on the neck disability index (NDI), participants were classified into no (NDI ≤ 8%, n = 31, reference group), mild (NDI = 10%-20%, n = 43), or moderate/severe (NDI ≥ 22%, n = 18) disability groups. Data were collected on bodily pain distribution and severity and psychological measures including depression, anxiety, pain-catastrophizing, and fear-avoidance beliefs using validated scales. Participants attended 1 session of quantitative sensory testing performed according to a standardized protocol, including local and remote thermal and mechanical pain thresholds, temporal summation of pain (TSP), conditioned pain modulation, and an exercise-induced analgesia paradigm. Compared with participants with no and mild disability, those with moderate/severe disability showed more widespread pain, cold and mechanical hyperalgesia at a remote nonpainful site, and significantly higher TSP. Participants with mild disability demonstrated significantly higher TSP than those with no disability. These group differences were attenuated after adjusting for depression or anxiety, indicating these psychological factors may mediate the somatosensory changes associated with neck disability. Group differences were not found for conditioned pain modulation or exercise-induced analgesia. These findings suggest that heightened pain facilitation, rather than impaired pain inhibition may underpin nociplastic pain in participants with moderate/severe disability, and it may be associated with depression and anxiety. Clinicians should be aware that individuals with work-related neck pain presenting with moderate/severe disability display distinct somatosensory features and tailor management strategies accordingly.

Static and Dynamic Pain Sensitivity in Adults With Persistent Low Back Pain: Comparison to Healthy Controls and Associations With Movement-evoked Pain Versus Traditional Clinical Pain Measures

OBJECTIVES

Despite its impact, individual factors associated with persistent low back pain (LBP) remain poorly understood. This study investigated static and dynamic pain sensitivity in adults with persistent LBP versus pain-free controls; and investigated associations between pain sensitivity and 3 clinical pain measures: recalled, resting, and movement-evoked pain (MEP).

MATERIALS AND METHODS

A lifespan sample of 60 adults with persistent LBP and 30 age-matched/sex-matched controls completed 4 laboratory sessions. Static pain sensitivity (pressure pain threshold [PPT], heat pain threshold) and dynamic pain sensitivity (heat pain aftersensations [AS], temporal summation [TS] of second heat pain) were measured. Demographic and clinical factors collected were education, global cognition, and perceived health. Resting and recalled pain were measured via questionnaire, and MEP via the Back Performance Scale.

RESULTS

LBP participants demonstrated lower PPT remotely (hand; F1,84=5.34, P=0.024) and locally (low back; F1,84=9.55, P=0.003) and also had higher AS (F1,84=6.01, P=0.016). Neither static nor dynamic pain sensitivity were associated with recalled pain (P>0.05). However, static pain sensitivity (local PPT) explained an additional 9% variance in resting pain, while dynamic pain sensitivity (AS, TS) explained an additional 10% to 12% variance in MEP.

DISCUSSION

This study characterized pain sensitivity measures among individuals with persistent LBP and suggests static pain sensitivity plays a larger role in resting pain while dynamic pain sensitivity plays a larger role in MEP. Future studies will confirm these relationships and elucidate the extent to which changes in static or dynamic pain sensitivity predict or mediate clinical pain among adults with persistent LBP.

Pressure Pain Threshold in Patients With Chronic Pain: A Systematic Review and Meta-Analysis

INTRODUCTION

In chronic pain conditions, the pressure pain threshold has been used to investigate the presence of central sensitization.

METHODS

A systematic review and meta-analysis were conducted to compare the threshold in chronic pain patients and healthy individuals. Ovid MEDLINE and Embase up to July 2019 were used to conduct the search. Search strategy included terms and sets of terms that describe the concepts "sensory testing" and "pain measurement."

RESULTS

The included studies consisted of 24 were case-control studies and 12 cross-sectional studies. The pooled total sample size was 1280 cases of patients with different diagnoses of chronic pain and 1463 healthy controls. Among the included studies, 32 reported a significant decrease of the pressure pain threshold among patients compared with the controls and four reported no statistically significant difference. The pooled pressure pain threshold mean difference was -1.17 (95% confidence interval = -1.45 to -0.90). There was, however, evidence of significant heterogeneity across the studies (I2 = 87.42%, P < 0.001).

CONCLUSIONS

Patients who experience chronic pain have a significantly lower pressure pain threshold compared with healthy controls. Future research is needed to elucidate factors attributed to the change in pressure pain threshold among patients with chronic pain, as well as the time that the central sensitization occurs.

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.

Hypoalgesic Effects of Transcutaneous Electrical Nerve Stimulation Combined With Joint Manipulation: A Randomized Clinical Trial

OBJECTIVE

The objective of this study was to compare the hypoalgesic effects of isolated or combined use of transcutaneous electrical nerve stimulation (TENS) and cervical joint manipulation (JM) in asymptomatic participants.

METHODS

One hundred and forty-four healthy participants aged 18 to 30 years old were randomly assigned to 1 of 4 groups (n = 36 per group): active TENS + active JM, active TENS + placebo JM, placebo TENS + active JM, and placebo TENS + placebo JM. Active or placebo TENS was applied to the dominant forearm. JM was applied to the C6-7 segments. The pressure pain threshold was measured pre- and postintervention and after 20 minutes on the forearm and tibialis anterior of the dominant side.

RESULTS

Segmental hypoalgesia was greater in the group active TENS + active JM compared with active TENS + placebo JM (P = .002), placebo TENS + active JM (P < .0001), and placebo TENS + placebo JM (P < .0001). For the extrasegmental hypoalgesia, active TENS + active JM had greater hypoalgesic effect compared with active TENS + placebo JM (P = .033), placebo TENS + active JM (P = .002), and placebo TENS + placebo JM (P < .0001).

CONCLUSION

TENS and JM produced hypoalgesia when used alone and, when the treatments were combined, a higher segmental and extrasegmental hypoalgesic effect was obtained in asymptomatic participants.

Sensory Processing in People With and Without Tendinopathy: A Systematic Review With Meta-analysis of Local, Regional, and Remote Sites in Upper- and Lower-Limb Conditions

OBJECTIVE

To synthesize results of somatosensory processing tests in people with upper- and lower-limb tendinopathy, compared to controls.

DESIGN

Systematic review with meta-analysis.

LITERATURE SEARCH

Four electronic databases (MEDLINE, CINAHL Plus, SPORTDiscus, and Embase) were searched.

STUDY SELECTION CRITERIA

Included studies measured a domain of sensory processing and compared a tendinopathy group to a healthy control group.

DATA SYNTHESIS

Meta-analysis was conducted for outcomes with homogeneous data from at least 2 studies. Upper- and lower-limb conditions were compared and outcomes were examined by measurement site (local, regional, or remote to location of pain).

RESULTS

Of the 30 studies included, 18 investigated lateral elbow tendinopathy. The most commonly assessed outcome measures were pressure pain threshold (PPT) and thermal pain threshold. There was moderate evidence for local and regional reduction of PPT in upper-limb tendinopathies, but not at remote sites. In lower-limb tendinopathies, there was conflicting evidence regarding reduced PPT at local sites and limited evidence of normal PPT at remote sites. There was moderate evidence of sensitization of thermal pain threshold at local sites in upper-limb tendinopathies and limited evidence of no difference in thermal pain threshold in lower-limb tendinopathies. Findings across other domains were variable.

CONCLUSION

Sensory processing was different between upper-limb tendinopathy and lower-limb tendinopathy. Upper-limb tendinopathies showed signs consistent with primary and secondary hyperalgesia, but lower-limb tendinopathies did not. There was mixed evidence for primary hyperalgesia and limited evidence against secondary hyperalgesia. J Orthop Sports Phys Ther 2021;51(1):12-26. doi:10.2519/jospt.2021.9417.

The Association Between Conditioned Pain Modulation and Manipulation-induced Analgesia in People With Lateral Epicondylalgia

OBJECTIVES

Conditioned pain modulation (CPM) and manipulation-induced analgesia (MIA) may activate similar neurophysiological mechanisms to mediate their analgesic effects. This study assessed the association between CPM and MIA responses in people with lateral epicondylalgia.

MATERIALS AND METHODS

Seventy participants with lateral epicondylalgia were assessed for CPM followed by MIA. A single assessor measured pressure pain thresholds (PPT) before, during, and after cold water immersion (10°C) of the asymptomatic hand and contralateral lateral glide (CLG) mobilization of the neck. For analyses, linear mixed models evaluated differences in CPM and MIA responses. Pearson partial correlations and regression analyses evaluated the association between CPM and MIA PPT.

RESULTS

There was a significant increase (CPM and MIA, P<0.001) in PPT from baseline during the interventions (CPM mean: 195.84 kPa for elbow and 201.87 kPa for wrist, MIA mean: 123.01 kPa for elbow and 126.06 kPa for wrist) and after the interventions (CPM mean: 126.06 kPa for elbow, 114.24 kPa for wrist, MIA mean: 123.50 kPa for elbow and 122.16 kPa for wrist). There were also significant moderate and positive partial linear correlations (r: 0.40 to 0.54, P<0.001) between CPM and MIA measures, controlling for baseline measures. Regression analyses showed that CPM PPT was a significant predictor of MIA PPT (P<0.001) and the models explained between 73% and 85% of the variance in MIA PPT.

DISCUSSION

This study showed that CPM and MIA responses were significantly correlated and that the CPM response was a significant predictor of MIA response.

Evaluating the immediate effect of forearm and wrist orthoses on pain and function in individuals with lateral elbow tendinopathy: A systematic review

BACKGROUND

Lateral elbow tendinopathy is associated with pain during gripping, with forearm/wrist orthoses prescribed for treatment.

OBJECTIVES

To investigate the immediate effects of forearm and/or wrist orthoses on outcome measures of pain and function in individuals with lateral elbow tendinopathy.

DESIGN

Systematic review METHODS: Four electronic databases were searched to identify randomised controlled trials reporting the immediate effects of forearm and/or wrist orthoses on pain and function in individuals with lateral elbow tendinopathy. The quality of evidence was rated from high to very low, using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) for the primary outcomes. Where possible, standardised mean difference (SMD) and 95% confidence intervals were calculated to compare post measures between forearm and/or wrist orthoses and control/placebo conditions.

RESULTS

The search revealed 1965 studies, of which, seven randomised crossover trials were included. Using the GRADE approach there was low quality evidence revealing a significant decrease in pain during contraction (SMD range -0.65 to -0.83) with forearm orthoses compared to a control/placebo condition. Low quality evidence revealed improvements in pain-free grip strength with the use of a forearm orthosis (SMD range 0.24-0.38), but not maximal grip strength (SMD range 0.14-0.15). Low quality evidence revealed a static wrist orthosis did not improve pain-free grip strength (SMD -0.08) or maximal grip strength (SMD -0.22).

CONCLUSION

There is low quality evidence that forearm orthoses can immediately reduce pain during contraction and improve pain-free grip strength but not maximal grip strength in individuals with lateral elbow tendinopathy.

Bilateral sensory and motor as well as cognitive differences between persons with and without musculoskeletal disorders of the wrist and hand

BACKGROUND

Sensory and motor disturbances are characteristic of musculoskeletal injuries and conditions. Rehabilitation interventions aimed at remediating these disturbances are traditionally exclusively targeted to the affected area. However, there is some evidence of bilateral changes in sensory and motor function associated with unilateral injuries and conditions suggesting central changes. Deficits on specific cognitive tasks have also been documented in persons with chronic pain.

PURPOSE

The purpose of the present study was to determine if participants with unilateral pain arising from heterogeneous wrist/hand injuries and conditions demonstrate bilateral changes in sensory and motor functions as well as cognitive deficits.

DESIGN/METHODS

Sensory (Pressure Pain Thresholds, Two Point Orientation Discrimination), Motor (grip strength and Purdue Pegboard), and Cognitive function (Stroop test and mental rotation task) were measured in 30 participants with wrist/hand pain and 30 healthy control participants in an observational cross-sectional study.

RESULTS

Participants with unilateral wrist/hand pain demonstrated differences in cognitive function measured with the Stroop test (p = 0.03). They also demonstrated bilateral sensorimotor differences in pressure pain thresholds (p = 0.03), grip strength (p = 0.00) and Purdue pegboard test (p = 0.03) results compared to healthy control participants.

CONCLUSION

Cognitive as well as bilateral alterations in sensory and motor function in participants with musculoskeletal injuries and conditions suggest central changes are involved in their pathophysiology. These findings in persons with heterogeneous injuries/conditions suggest that these changes are not specific to an injury/condition. Bilateral sensorimotor changes have important implications with regards to the pathophysiology of musculoskeletal disorders of the wrist/hand, for rehabilitative interventions and research.

Local and Widespread Pressure Pain Hyperalgesia Is Not Side Specific in Females with Unilateral Neck Pain that Can Be Reproduced during Passive Neck Rotation

Current evidence for widespread hyperalgesia in non-specific neck pain (NSNP) is unclear. It is currently recommended to group NSNP patients according to pain-provoking movements. The aim of this study was to investigate local and widespread pain sensitivity in females with unilateral NSNP that is reproducible during passive neck rotation compared with matched controls, and to compare the side specific effect of pain location on pressure pain sensitivity among females with unilateral NSNP. Thirty-six females with unilateral NSNP evoked during passive ipsilateral (n = 20) or contralateral (n = 16) rotation toward the painful side were compared with 20 controls. Participants reported their pain intensity at rest and during passive neck rotation and completed the Neck Disability Index. Pressure pain thresholds (PPTs) were assessed bilaterally over the anterior scalene; the sternocleidomastoid; the levator scapulae; lateral to the spinous process of C6; the median, ulnar, and radial nerves; and the tibialis anterior. The ANOVA revealed lower PPTs in females with unilateral NSNP compared with the controls (all at p < 0.001), but no differences were found between the sides, nor was there any Group × side interaction. Among females with NSNP, those with higher pain intensity during ipsilateral rotation toward the painful side showed lower PPTs over the anterior scalene, median nerve, ulnar nerve, and tibialis anterior (all, p < 0.05) than females with higher pain intensity during contralateral rotation toward the painful side. These findings demonstrated bilateral local and widespread pressure pain hyperalgesia in females with unilateral NSNP that was reproducible during passive neck rotation compared with controls. There was no side specific effect of pain location on PPTs among females with unilateral NSNP.

Chronic pain intervention using pulsed shortwave therapy: the relationship between pain demographics and central sensitization inventory

Aim: The central sensitization inventory (CSI) is a validated, patient-reported questionnaire that quantifies symptoms of hypersensitivity disorders such as chronic pain, for which central sensitization (CS) may be the etiology. Objective: To investigate the analgesic effectiveness of ActiPatch and analyze the relationship between baseline CSI scores and demographics of chronic pain sufferers. Methods: Upon completing a 7-day ActiPatch trial, baseline CSI scores along with other assessment measures were obtained via e-mail from 174 chronic pain sufferers. Conclusion: CSI scores were positively correlated with gender (higher for women), baseline visual analog scale scores and pain duration. ActiPatch was found to be effective in reducing baseline pain for all subjects by an average of 4.3 visual analog scale points.

Widespread Pressure Pain Hypersensitivity, Health History, and Trigger Points in Patients with Chronic Neck Pain: A Preliminary Study

Background

Pain sensitivity in chronic neck pain patients may be influenced by health conditions related to higher levels of widespread pressure pain hypersensitivity (sensitization). Trigger points have also been reported to play a role in the sensitization process.

Objectives

To investigate the association between pressure pain thresholds, trigger points, and health conditions in patients with chronic neck pain.

Design

Original research, preliminary study.

Setting

A private clinic.

Subjects

Thirty-four chronic mechanical neck pain patients and 34 chronic whiplash-associated neck pain patients, giving a final sample of 68 chronic neck pain patients.

Methods

Patients underwent an assessment of pressure pain thresholds over the upper trapezius, extensor carpi radialis longus, and tibialis anterior muscles and were screened for the presence of trigger points in the upper trapezius muscle. Further, information about health history conditions was obtained and collected in a form.

Results

Significantly negative correlations between all pressure pain thresholds and duration of health history conditions were found (all P &lt; 0.02). Significantly lower pressure pain thresholds (all P &lt; 0.01) were found in patients with active trigger points as compared with those with latent trigger points.

Conclusion

Widespread pressure pain hypersensitivity was associated with duration of health history conditions, suggesting that long-lasting health complaints may act as a triggering/perpetuating factor, driving sensitization in individuals with chronic neck pain. Active trigger points may be associated with higher widespread pressure hypersensitivity.

The Prognostic Value of Pain Sensitization in Patients With Lateral Epicondylitis

PURPOSE

Pain sensitization is a contributing factor to conditions of chronic pain. The aim of this study was to evaluate the influence of pain sensitization on the prognosis of lateral epicondylitis (LE) treated by self-stretching exercises and the use of a counterforce brace.

METHODS

We enrolled 131 patients who presented with isolated LE symptoms for less than 6 months. We initially measured pain sensitization by assessing patients' pressure pain thresholds (PPTs) in the contralateral middorsal forearm and administering a pain sensitization questionnaire (PSQ). For outcome assessments, we assessed the self-administered, patient-reported Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire at 6 and 12 months' follow-up.

RESULTS

Initial PSQ scores correlated moderately with baseline DASH scores and slightly with symptom duration; PPTs correlated slightly with baseline DASH scores. After we accounted for confounding variables, patient-reported disability was associated with lower PPTs, higher PSQ scores, and manual labor at 6 months. These 3 factors accounted for 36% of variance in the DASH scores; however, at 12 months only the PSQ score was associated with higher DASH scores, accounting for 14% of variance.

CONCLUSIONS

Pain sensitization during the early stages of LE correlated with initial symptom severity and duration and was associated with persistently increasing disability after 1 year of nonsurgical treatment. More research is needed to show whether early identification and treatment of pain sensitization will enhance LE treatment outcomes.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Relationship between ultrasound detected tendon abnormalities, and sensory and clinical characteristics in people with chronic lateral epicondylalgia

Objective

To investigate the relationship between tendon structural changes determined by static ultrasound images (US) and sensory changes using quantitative sensory testing (QST), and clinical measures in lateral epicondylalgia.

Materials and methods

Both elbows of 66 adult participants with a clinical diagnosis of lateral epicondylalgia were investigated. Using a standardised ultrasound image rating scale, common extensor hypoechogenicity, heterogenicity, neovascularity, and bony abnormalities at the enthesis were scored, and tendon thickness (longitudinal and transverse plane) was measured by a trained assessor. Sensory measures of pressure, heat and cold pain thresholds and vibration detection threshold were recorded. Pain and function were assessed using the patient-rated tennis elbow (PRTEE), pain-free grip strength, pain visual analog scale (PVAS) and quality of life (EuroQoL EQ -5D). Univariate and multivariate linear regression analyses were used to explore the association between tendon structural, sensory and clinical variables which were adjusted for age, gender and duration of symptoms.

Results

A negative correlation was identified between the presence of neovascularity and cold pain threshold (P = 0.015). Multiple regression analyses revealed that a combination of female gender (P = 0.044) and transverse tendon thickness (P = 0.010) were significantly associated with vibration detection threshold in affected elbows, while gender (P = 0.012) and total ultrasound scale score (P = 0.024) were significantly associated with heat pain threshold and vibration detection threshold in unaffected elbows. Heat pain threshold and gender were significantly associated with pain and disability (PRTEE; P < 0.001), and pain-free grip strength (P < 0.001) respectively, in the affected elbows.

Conclusion

Generally, structural and sensory measures were weakly correlated. However, neovascularity and transverse tendon thickness may be related to sensory system changes in LE.

Transcutaneous electrical nerve stimulation and cervical joint manipulation on pressure pain threshold

Aim: Transcutaneous electrical nerve stimulation (TENS) and cervical joint manipulation (CJM) are often used for pain treatment. Methods: A total of 144 healthy subjects will be randomly allocated into four groups: active TENS and CJM, placebos TENS and CJM, placebo TENS and active CJM, active TENS and placebo CJM. TENS will be applied for 20 min followed by CJM. All subjects will be assessed before, during and after interventions, using a digital pressure algometer. Discussion: This is the first study to assess the combined effects of TENS and CJM on pressure pain threshold in healthy individuals. It is possible that both methods combined can enhance the hypoalgesic effect because they activate different analgesic pathways.

Study registration: NCT03531541 (ClinicalTrials.gov).

Laterality recognition of images, motor performance, and aspects related to pain in participants with and without wrist/hand disorders: An observational cross-sectional study

OBJECTIVE

Musculoskeletal disorders are associated with altered sensory, proprioceptive and cognitive processes. Sensory processes affect the internal cortical representation of the body in space, the body schema, which in turn influences motor control. The purpose of this study was to determine if participants with wrist/hand disorders had impaired performance on a task associated with the body schema, the Left/Right Judgement Task (LRJT) and secondly how LRJT performance, motor performance, disability, pain and related aspects are associated.

METHODS

Fifteen healthy control participants and 15 participants with hand/wrist pain were asked to determine the laterality of images of hands. Measures of motor performance (Purdue Pegboard test), self-reported disability (Australian Canadian Hand Index), and pain related aspects (pain intensity, symptom duration, pain interference and affective distress) were recorded.

RESULTS

Participants with wrist/hand pain scored lower on all segments of the Purdue Pegboard test. There were differences in LRJT performance between groups for both Accuracy (p = 0.03) and Reaction Time (RT) (p < 0.01). There was no correlation between RT and Accuracy with pain intensity, pain duration, and disability. Both motor performance (r = 0.58-0.64) and LRJT performance Accuracy (r = 0.59) and RT (r = -0.56) were correlated with affective distress. A significant correlation was observed between RT and motor performance in healthy control participants (r = -0.56, p = 0.03) but not in participants with wrist/hand pain (r = -0.26, p = 0.44).

CONCLUSIONS

LRJT and motor performance was correlated with affective distress in participants with wrist/hand pain suggestive of complex interactions between cognitive-affective processes and sensorimotor integration.

Assessment and manifestation of central sensitisation across different chronic pain conditions

Different neuroplastic processes can occur along the nociceptive pathways and may be important in the transition from acute to chronic pain and for diagnosis and development of optimal management strategies. The neuroplastic processes may result in gain (sensitisation) or loss (desensitisation) of function in relation to the incoming nociceptive signals. Such processes play important roles in chronic pain, and although the clinical manifestations differ across condition processes, they share some common mechanistic features. The fundamental understanding and quantitative assessment of particularly some of the central sensitisation mechanisms can be translated from preclinical studies into the clinic. The clinical perspectives are implementation of such novel information into diagnostics, mechanistic phenotyping, prevention, personalised treatment, and drug development. The aims of this paper are to introduce and discuss (1) some common fundamental central pain mechanisms, (2) how they may translate into the clinical signs and symptoms across different chronic pain conditions, (3) how to evaluate gain and loss of function using quantitative pain assessment tools, and (4) the implications for optimising prevention and management of pain. The chronic pain conditions selected for the paper are neuropathic pain in general, musculoskeletal pain (chronic low back pain and osteoarthritic pain in particular), and visceral pain (irritable bowel syndrome in particular). The translational mechanisms addressed are local and widespread sensitisation, central summation, and descending pain modulation.

Significance

Central sensitisation is an important manifestation involved in many different chronic pain conditions. Central sensitisation can be different to assess and evaluate as the manifestations vary from pain condition to pain condition. Understanding central sensitisation may promote better profiling and diagnosis of pain patients and development of new regimes for mechanism based therapy. Some of the mechanisms underlying central sensitisation can be translated from animals to humans providing new options in development of therapies and profiling drugs under development.

Isometric Exercise Above but not Below an Individual's Pain Threshold Influences Pain Perception in People With Lateral Epicondylalgia

OBJECTIVE

To examine the acute effects of isometric exercise of different intensities on pain perception in individuals with chronic lateral epicondylalgia.

MATERIALS AND METHODS

Participants performed 3 experimental tasks completed in a randomized order on separate days: control (no exercise) and isometric wrist extension (10×15 s) at load 20% below (infrathreshold), and 20% above (suprathreshold) an individual's pain threshold. Self-reported pain intensity (11-point numeric rating scales), pressure pain threshold, and pain-free grip were assessed by a blinded examiner before, immediately after, and 30 minutes after task performance. Relation analysis between pain ratings and clinical variables, including pain and disability and kinesiophobia was performed.

RESULTS

Twenty-four individuals with unilateral lateral epicondylalgia of median 3-month duration participated. Pain intensity during contraction was significantly higher during suprathreshold exercise than infrathreshold exercise (mean difference in numeric rating scale 1.0; 95% confidence interval, 0.4-1.5; P=0.002). Pain intensity during suprathreshold exercise was significantly correlated with pain and disability (R=0.435, P=0.034) and kinesiophobia (R=0.556, P=0.005). Pain intensity was significantly higher immediately after performance of suprathreshold exercise, compared with infrathreshold exercise (P=0.01) and control (P<0.001) conditions, whereas infrathreshold exercise and control conditions were comparable. Thirty minutes later, pain levels remained significantly higher for suprathreshold exercise compared with infrathreshold exercise (P=0.043). Pressure pain threshold and pain-free grip showed no significant effects of time, condition, or time×condition (P>0.05).

DISCUSSION

Individuals with lateral epicondylalgia demonstrated increased pain intensity after an acute bout of isometric exercise performed at an intensity above, but not below, their individual pain threshold. Further investigation is needed to determine whether measurement of an individual's exercise induced pain threshold may be important in reducing symptom flares associated with exercise.