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

Exploring Symptom Responses to Upper Limb Neural Test Variations of the Radial Nerve in Patients With Lateral Epicondylalgia: An Observational Study

OBJECTIVE

Clinical practice guidelines recommend the radial nerve mechanosensitivity evaluation in patients with lateral epicondylalgia. Despite different positions and sequences having been described, no research analyzed how each variation triggers symptoms associated with lateral epicondylalgia. The aim of this study was to explore the effects of different positions and sequences in the upper limb neural tension test 2b (ULNT2b) in symptom responses in patients with lateral epicondylalgia.

METHODS

In this observational study, 66 patients underwent 4 test conditions: standard ULNT2b, ULNT2b proximal to distal, ULNT2B with resisted supination, and resisted supination isolated. Paresthesia sensations, symptom reproduction, pain intensity (measured using a visual analog scale), and distribution of painful symptoms data were collected.

RESULTS

Significant differences in paresthesia sensations were observed between groups, with significant differences between the standard ULNT2B and other ULNT variations or resisted supination maneuvers. Symptom reproduction also differed significantly across groups, with significant differences between the standard ULNT2B and other ULNT or resisted supination tests. The positive/negative test and percentage of distribution of painful symptoms scores varied significantly across 4 conditions in both lateral and frontal views. Although pain intensity scores during tests were comparable among the tests, distribution of painful symptoms differed significantly.

CONCLUSION

Variations in the ULNT2b test can affect symptom responses in patients with lateral epicondylalgia. The standard ULNT2b test appears more effective at reproducing symptoms, intensity of paresthesia, and distribution of painful symptoms compared to other ULNT variations and the resisted supination test.

IMPACT

ULNT2b sequences have been shown to elicit varying responses concerning paresthesia, replication of familiar symptoms, positive/negative test results, and distribution of painful symptoms. Clinicians should consider specific test variations during the patients' radial nerve mechanosensitivity assessment to identify aggravating factors reproducing recognizable symptoms. A control group of asymptomatic participants and the role of presence of other comorbidities, psychological factors, or the duration of symptoms were not considered in this study and might play an important role influencing the results of the tests.

Alteration of Interhemispheric Inhibition in Patients With Lateral Epicondylalgia

Patients with lateral epicondylalgia (LE) show alterations in the primary motor cortex (M1) contralateral to the affected side. Cortical alterations have been investigated by measuring intracortical facilitation/inhibition; however, their association with pain remains controversial. Furthermore, no studies have investigated changes in interhemispheric inhibition (IHI). IHI can be assessed using the ipsilateral silent period (iSP) known as the temporary inhibition of electromyographic activity evoked by transcranial magnetic stimulation in the ipsilateral M1 of the contracting muscle. To better understand the relationship between cortical alterations and pain in LE, this observational study investigated the relationship between iSP and pain in LE. Twenty-seven healthy volunteers and 21 patients with LE were recruited. The duration of iSP in the extensor carpi radialis brevis was measured. The IHI asymmetry ratio was calculated to determine the IHI balance. Pain and disability were scored using the Japanese version of the patient-rated elbow evaluation. We observed increased inhibitory input from the ipsilateral M1 on the affected side to the contralateral M1 in LE. Additionally, the IHI balance correlated with pain severity. Hence, regulating imbalanced IHI can potentially decrease lateral elbow pain in LE. PERSPECTIVE: Patients with lateral epicondylalgia (LE) experience persistent pain and cortical alterations. However, there is no established relationship between cortical alterations and pain. This study demonstrated that the interhemispheric inhibition (IHI) balance is correlated with pain. Regulating imbalanced IHI can potentially decrease lateral elbow pain in patients with LE.

Bilateral Corticomotor Reorganization and Symptom Development in Response to Acute Unilateral Hamstring Pain: A Randomized, Controlled Study

Accumulating evidence demonstrates that pain induces adaptations in the corticomotor representations of affected muscles. However, previous work has primarily investigated the upper limb, with few studies examining corticomotor reorganization in response to lower limb pain. This is important to consider, given the significant functional, anatomical, and neurophysiological differences between upper and lower limb musculature. Previous work has also focused on unilateral corticomotor changes in response to muscle pain, despite an abundance of literature demonstrating that unilateral pain conditions are commonly associated with bilateral motor dysfunction. For the first time, this study investigated the effect of unilateral acute hamstring pain on bilateral corticomotor organization using transcranial magnetic stimulation (TMS) mapping. Corticomotor outcomes (TMS maps), pain, mechanical sensitivity (pressure pain thresholds), and function (maximal voluntary contractions) were recorded from 28 healthy participants at baseline. An injection of pain-inducing hypertonic (n = 14) or pain-free isotonic (n = 14) saline was then administered to the right hamstring muscle, and pain ratings were collected every 30 seconds until pain resolution. Follow-up measures were taken immediately following pain resolution and at 25, 50, and 75 minutes post-pain resolution. Unilateral acute hamstring pain induced bilateral symptom development and changes in corticomotor reorganization. Two patterns of reorganization were observed-corticomotor facilitation and corticomotor depression. Corticomotor facilitation was associated with increased mechanical sensitivity and decreased function bilaterally (all P < .05). These effects persisted for at least 75 minutes after pain resolution. PERSPECTIVE: These findings suggest that individual patterns of corticomotor reorganization may contribute to ongoing functional deficits of either limb following acute unilateral lower limb pain. Further research is required to assess these adaptations and the possible long-term implications for rehabilitation and reinjury risk in cohorts with acute hamstring injury.

Trials and tribulations of transparency related to inconsistencies between plan and conduct in peer-reviewed physiotherapy publications: A methodology review

RATIONALE

The physiotherapy profession strives to be a leader in providing quality care and strongly recognizes the value of research to guide clinical practice. Adherence to guidelines for research reporting and conduct is a significant step towards high-quality, transparent and reproducible research.

AIM/OBJECTIVE

Assess integrity between planned and conducted methodology in randomized controlled trials (RCTs) and systematic reviews (SRs) published in physiotherapy journals.

METHODS

Eighteen journals were manually searched for RCTs and SRs published from 1 July 2021 through 31 December 2021. Studies were included if the journal or specific study was indexed in PubMed and published/translated in English. Descriptive statistics determined congruence between preregistration data and publication.

RESULTS

Forty RCTs and 68 SRs were assessed. Forty-three SRs included meta-analysis (MA). Of the 34 registered RCTs, 7 (20.6%) had no discrepancy between the registration and publication. Two trials (5.9%) addressed all discrepancies, 4 (11.8%) addressed some and 21 (61.8%) did not address any discrepancies. Of the 36 registered MAs, 33 (91.7%) had discrepancies between the registration and publication. Two (5.6%) addressed all discrepancies and three (8.3%) had no discrepancies. Eight SRs without MA published information not matching their registration, and none provided justification for the discrepancies.

CONCLUSION

Most RCTs/SRs were registered; the majority had discrepancies between preregistration and publication, potentially influencing the outcomes and interpretations of findings. Journals should require preregistration and compare the submission with the registration information when assessing publication suitability. Readers should be aware of these inconsistencies and their implications when interpreting and translating results into practice.

Gut microbiota changes in patients with hypertension: A systematic review and meta-analysis

Hypertension is a major public health issue worldwide. The imbalance of gut microbiota is thought to play an important role in the pathogenesis of hypertension. The authors conducted the systematic review and meta-analysis to clarify the relationship between gut microbiota and hypertension through conducting an electronic search in six databases. Our meta-analysis included 19 studies and the results showed that compared with healthy controls, Shannon significantly decreased in hypertension [SMD = -0.13, 95%CI (-0.22, -0.04), p = .007]; however, Simpson [SMD = -0.01, 95%CI (-0.14, 0.12), p = .87], ACE [SMD = 0.18, 95%CI (-0.06, 0.43), p = .14], and Chao1 [SMD = 0.11, 95%CI (-0.01, 0.23), p = .08] did not differ significantly between hypertension and healthy controls. The F/B ratio significantly increased in hypertension [SMD = 0.84, 95%CI (0.10, 1.58), p = .03]. In addition, Shannon index was negatively correlated with hypertension [r = -0.12, 95%CI (-0.19, -0.05)], but had no significant correlation with SBP [r = 0.10, 95%CI (-0.19, 0.37)] and DBP [r = -0.39, 95%CI (-0.73, 0.12)]. At the phylum level, the relative abundance of Firmicutes [SMD = -0.01, 95%CI (-0.37, 0.34), p = .94], Bacteroidetes [SMD = -0.15, 95%CI (-0.44, 0.14), p = .30], Proteobacteria [SMD = 0.25, 95%CI (-0.01, 0.51), p = .06], and Actinobacteria [SMD = 0.21, 95%CI (-0.11, 0.53), p = .21] did not differ significantly between hypertension and healthy controls. At the genus level, compared with healthy controls, the relative abundance of Faecalibacterium decreased significantly [SMD = -0.16, 95%CI (-0.28, -0.04), p = .01], while the Streptococcus [SMD = 0.20, 95%CI (0.08, 0.32), p = .001] and Enterococcus [SMD = 0.20, 95%CI (0.08, 0.33), p = .002] significantly increased in hypertension. Available evidence suggests that hypertensive patients may have an imbalance of gut microbiota. However, it still needs further validation by large sample size studies of high quality.

Sensitization-associated and neuropathic-associated symptoms in patients with unilateral lateral elbow tendinopathy: an exploratory study

OBJECTIVES

We evaluate the presence of sensitization-associated symptoms and neuropathic pain features and identify if there is an association between these symptoms and pressure pain sensitivity, pain, and related-disability in lateral elbow tendinopathy.

METHODS

Thirty-seven (43% women, age: 45.5 ± 9.5 years) patients with lateral elbow tendinopathy completed: demographic (i.e. age, height, and weight); clinical (i.e. pain history, pain intensity, and Disabilities of the Arm, Shoulder and Hand); and psychophysical (i.e. pressure pain thresholds at the elbow, cervical spine, hand, and leg) outcomes, and the Central Sensitization Inventory and Self-administered Leeds Assessment of Neuropathic Symptoms and Signs questionnaires. Step-wise multiple linear regression models were performed to identify predictors of sensitization- or neuropathic-associated symptoms.

RESULTS

Six (16%) patients exhibited sensitization-associated symptoms (mean: 46.5, SD: 6.1), whereas 13 (35%) patients showed neuropathic-associated symptoms (mean: 13.5; SD: 1.4). Sensitization-associated symptoms were positively associated with neuropathic-associated symptoms (r = 0.538, P = .001) and negatively associated with pressure pain thresholds at the leg (r = -0.378, P = .021). Neuropathic-associated symptoms were positively associated with related-disability (r = 0.479, P = .003) and negatively associated with pressure pain threshold at the elbow (r = -0.394, P = .017). Stepwise regression analyses revealed that neuropathic-like symptoms explained 26.8% of the variance of sensitization symptoms (r2: 0.268), whereas pressure pain threshold at the elbow explained an additional 6.6% to neuropathic-like symptoms (r2: 0.334).

CONCLUSION

This explorative study identified sensitization- and neuropathic-associated symptoms in 16% and 35% of the people with lateral elbow tendinopathy. Sensitization- and neuropathic-associated symptoms were associated. Pressure pain sensitivity at the elbow (peripheral sensitization) was associated with neuropathic -associated symptoms.

Exercise for rotator cuff tendinopathy: Proposed mechanisms of recovery

Rotator cuff (RC) tendinopathy is a common recurrent cause of shoulder pain, and resistance exercise is the first-line recommended intervention. Proposed causal mechanisms of resistance exercise for patients with RC tendinopathy consist of four domains: tendon structure, neuromuscular factors, pain and sensorimotor processing, and psychosocial factors. Tendon structure plays a role in RC tendinopathy, with decreased stiffness, increased thickness, and collagen disorganization. Neuromuscular performance deficits of altered kinematics, muscle activation, and force are present in RC tendinopathy, but advanced methods of assessing muscle performance are needed to fully assess these factors. Psychological factors of depression, anxiety, pain catastrophizing, treatment expectations, and self-efficacy are present and predict patient-reported outcomes. Central nervous system dysfunctions also exist, specifically altered pain and sensorimotor processing. Resisted exercise may normalize these factors, but limited evidence exists to explain the relationship of the four proposed domains to trajectory of recovery and defining persistent deficits limiting outcomes. Clinicians and researchers can use this model to understand how exercise mediates change in patient outcomes, develop subgroups to deliver patient-specific approach for treatment and define metrics to track recovery over time. Supporting evidence is limited, indicating the need for future studies characterizing mechanisms of recovery with exercise for RC tendinopathy.

A Closer Look at Localized and Distant Pressure Pain Hypersensitivity in People With Lower Extremity Overuse Soft-Tissue Painful Conditions: A Systematic Review and Meta-Analysis

OBJECTIVE

The nociceptive pain processing of soft-tissue overuse conditions is under debate because no consensus currently exists. The purpose of this meta-analysis was to compare pressure pain thresholds (PPTs) in symptomatic and distant pain-free areas in 2 groups: participants with symptomatic lower extremity overuse soft-tissue conditions and controls who were pain free.

METHODS

Five databases were searched from inception to December 1, 2021, for case-control studies comparing PPTs between individuals presenting with symptomatic lower extremity tendinopathy/overuse injury and controls who were pain free. Data extraction included population, diagnosis, sample size, outcome, type of algometer, and results. The methodological quality (Newcastle-Ottawa Quality Assessment Scale) and evidence level (Grading of Recommendations Assessment, Development, and Evaluation) were assessed. Meta-analyses of symptomatic, segmental related, and distant pain-free areas were compared.

RESULTS

After screening 730 titles and abstracts, a total of 19 studies evaluating lower extremity overuse conditions (Achilles or patellar tendinopathy, greater trochanteric pain syndrome, plantar fasciitis, and iliotibial band syndrome) were included. The methodological quality ranged from fair (32%) to good (68%). Participants with lower extremity overuse injury had lower PPTs in both the painful and nonpainful areas, mirrored test-site, compared with controls (affected side: mean difference [MD] = -262.92 kPa, 95% CI = 323.78 to -202.05 kPa; nonaffected side: MD = -216.47 kPa, 95% CI = -304.99 to -127.95 kPa). Furthermore, people with plantar fasciitis showed reduced PPTs in the affected and nonaffected sides at segmental-related (MD = -176.39 kPa, 95% CI = -306.11 to -46.68 kPa) and distant pain-free (MD = -97.27 kPa, 95% CI = 133.21 to -61.33 kPa) areas compared with controls.

CONCLUSION

Low- to moderate-quality evidence suggests a reduction of PPTs at the symptomatic area and a contralateral/mirror side in lower extremity tendinopathies and overuse conditions compared with pain-free controls, particularly in plantar fasciitis and greater trochanteric pain syndrome. Participants with plantar fasciitis showed a reduction of PPTs on the affected and non-affected sides at a segmental-related area (very low-quality evidence) and at a remote asymptomatic area (moderate-quality evidence).

IMPACT

Some overuse peripheral pain conditions may be more associated with pressure pain sensitivity than others. Accordingly, examination and identification of conditions more peripherally, centrally, or mixed mediated could potentially lead to more specific and different treatment strategies.