Evidence of Nervous System Sensitization in Commonly Presenting and Persistent Painful Tendinopathies: A Systematic Review

Effects of high frequency strengthening on pain sensitivity and function in female runners with chronic patellofemoral pain

OBJECTIVE

To investigate the effects of a high frequency strengthening program on function, pain, and pain sensitization in female runners with chronic patellofemoral pain (PFP).

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Thirty female runners (mean age 32 ± 8.1 years) with chronic PFP completed an 8-week home strengthening program.

MAIN OUTCOME MEASURES

Variables assessed at baseline, 8-weeks, and 12 weeks included single leg step down test (SLSD), pain, Anterior Knee Pain Scale (AKPS), University of Wisconsin Running Injury and Recovery Index (UWRI), and quantitative sensory testing.

RESULTS

There was large and statistically significant improvement at 8 and 12 weeks for average knee pain (ηp2 = 0.334, p < 0.001), worst knee pain (ηp2 = 0.351, p < 0.001), SLSD (ηp2 = 0.161, p = 0.001), AKPS (ηp2 = 0.463, p < 0.001), and UWRI (ηp2 = 0.366, p < 0.001). A medium to large effect and statistically significant improvement in pressure pain threshold testing was found for all local and remote structures (ηp2 range, 0.110 to 0.293, range p < 0.001 to p = 0.009) at 8 and 12 weeks.

CONCLUSIONS

There was a significant decrease in local and remote hyperalgesia via mechanical and thermal pain sensitivity testing in female runners with chronic PFP. There was a large effect and significant improvement in self-reported pain and function.

Conditioned Pain Modulation Does Not Differ Between People With Lower-Limb Tendinopathy and Nontendinopathy Controls: A Systematic Review With Individual Participant Data Meta-analysis

OBJECTIVE: To explore whether people with lower-limb tendinopathy have reduced relative conditioned pain modulation (CPM) when compared to nontendinopathy controls. DESIGN: Systematic review with individual participant data (IPD) meta-analysis. LITERATURE SEARCH: Eight databases were searched until August 29, 2022. STUDY SELECTION CRITERIA: Cross-sectional studies comparing the magnitude of the CPM effect in people with lower-limb tendinopathy to nontendinopathy controls in a case-control design. DATA SYNTHESIS: Included studies provided IPD, which was reported using descriptive statistics. Generalized estimating equations (GEEs) determined between-group differences in the relative CPM effect, when adjusting for co-variables. Study quality was assessed using a Joanna Briggs Institute checklist, and certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluations. RESULTS: Five records were included, IPD were provided for 4 studies (n = 219 with tendinopathy, n = 226 controls). The principal GEE (model 1) found no significant relative CPM effects for tendinopathy versus controls (B = -1.73, P = .481). Sex (B = 4.11, P = .160), age (B = -0.20, P = .109), and body mass index (B = 0.28, P = .442) did not influence relative CPM effect. The Achilles region had a reduced CPM effect (B = -22.01, P = .009). In model 2 (adjusting for temperature), temperature (B = -2.86, P = .035) and female sex (B = 21.01, P = .047) were associated with the size of the relative CPM effect. All studies were low-quality, and the certainty of the evidence was moderate. CONCLUSION: There were no between-group differences in the magnitude of the CPM effect, suggesting clinicians should manage lower-limb tendinopathy using interventions appropriate for peripherally dominant pain (eg, tendon loading exercises such as heavy slow resistance). Based on the "moderate"-certainty evidence, future studies are unlikely to substantially change these findings. J Orthop Sports Phys Ther 2023;54(1):1-10. Epub 19 October 2023. doi:10.2519/jospt.2023.11940.

Pain neuroscience education in persistent painful tendinopathies: A scoping review from the Tendon PNE Network

OBJECTIVE

to conduct and report a scoping review of the available evidence of the effects and content of pain neuroscience education for patients with persistent painful tendinopathies.

METHODS

PubMed, Embase, Web of Science, CINAHL, SPORTDiscus, and grey literature databases were searched from database inception to May 2022. Randomised and non-randomised controlled trials, non-controlled clinical trials, cohort studies, case series, case studies including people with persistent painful tendinopathy aged ≥18 years, a pain education intervention, and in English were included. Studies were excluded if they were cross-sectional studies, reviews, editorials, abstracts, or full-text not available or if included heterogeneous study cohorts, patients with tendon rupture, or patients with systemic diseases.

RESULTS

five studies (n = 164) were included. Pain neuroscience education entailed face-to-face discussion sessions or educational materials including videos, brochures, paper drawings, and review questions. All studies used pain neuroscience education in conjunction with other interventions, obtaining significant benefits in outcomes related to pain, physical performance, or self-reported function, among others.

CONCLUSIONS

The application of pain neuroscience education in conjunction with other interventions seemed to improve several outcomes. However, considering the current knowledge about tendon pain and the scarcity of well-designed trials studying pain neuroscience education in tendinopathy, additional research is needed.

Central sensitization syndrome in patients with rotator cuff tear: prevalence and associated factors

INTRODUCTION

A significant number of rotator cuff tear (RCT) patients developed chronic shoulder pain that did not correspond to physiological changes. Central sensitization syndrome (CSS) is a neurophysiological adaptation process that can result in hypersensitivity to peripheral stimuli. Although there is evidence of an association between CSS and musculoskeletal problems, no studies have focused on the association between CSS and RCT. The primary purpose of this study was to examine the prevalence of CSS in patients with RCT. The secondary purpose was to document the associated conditions and comorbidity that were associated with the CSS.

METHODS

This was a cross-sectional study of patients with RCT who completed the Central Sensitization Inventory (CSI). Patients with score of ≥ 40/100 were considered positive for CSS. Demographic and clinical data and CSI results were collected to analyze the prevalence and associated factors of CSS in RCT patients.

RESULTS

A total of 404 RCT patients were included, and the CSS prevalence was 39.4%. Compared to the non-CSS group, the CSS group had an odds ratio of 4.13 (95% CI, 2.70-6.32; p＜0.001) for ages 51-60, 3.07 (95% CI, 2.00-4.69; p＜0.001) for symptoms lasting more than 6 months, 6.08 (95% CI, 3.90-9.47; p＜0.001) for nonphysical laborers, 3.69 (95%CI, 2.42-5.61; p＜0.001) for long head of biceps (LHB) abnormality, 2.93 (95% CI, 1.93-4.45; p＜0.001) for concurrent shoulder stiffness, 4.82 (95% CI, 2.55-9.10; p＜0.001) for anxiety or panic episodes, and 2.11 (95% CI, 1.12, 4.00; p＜0.001) for depression.

CONCLUSIONS

The prevalence of CSS in patients with RCT was relatively high at 39.4%. The CSS was associated with higher age, female gender, and clinical findings of symptoms lasting over six months, nonphysical laborers, abnormal LHB, concurrent shoulder stiffness, anxiety, and depression.

Efficacy of Externally Paced Training on Pain in Tendinopathy: A Systematic Review and Meta Analysis

Tendinopathy is a common condition with treatments focused on local tissue adaptations. Externally paced loading programs are designed to cue (visually, auditorily, or temporally) a person as to when to perform an exercise repetition during a set of repetitions. Externally paced loading programs propose central and peripheral changes with tendinopathy but conclusions regarding their efficacy on pain outcomes remain limited. Our review seeks to explore the efficacy of externally paced loading as a method to reduce self-reported pain in tendinopathic conditions. An electronic database search was conducted of PubMed, SPORTDiscus, Scopus, and CINAHL databases. A total of 2,104 studies were identified after a preliminary search; four reviewers narrowed the selection to seven articles based on inclusion and exclusion criteria. Articles selected for review (patellar = three, Achilles = two, rotator cuff = one, and lateral elbow tendinopathy = one) were randomized control trials assessing the externally paced loading programs' efficacy on tendon pain compared to the control; all were included in the meta-analysis. This review identified no superiority in externally paced loading compared to alternative treatment. There were potential population differences between non-athletic and athletic populations as identified with subgroup analyses. Current activity levels, region of tendinopathy, and chronicity of symptoms may explain the variability of findings. There is little clinically significant evidence to support the use of externally paced loading programs for reducing tendon pain over standard clinical care based on a low level of certainty which is based on the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) of articles included in the review. Clinicians should interpret outcomes between athletic and non-athletic participants with caution as further high-quality studies are required to confirm specific clinical outcomes in these populations.

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.

The major pain source of rotator cuff-related shoulder pain: A narrative review on current evidence

BACKGROUND

Rotator cuff-related shoulder pain (RCRSP) was proposed to have a complex pain mechanism, but the exact aetiology is still unclear. A recent review summarised the updated research to analyse the traditional concept of shoulder impingement which may not be accurate. Current studies have demonstrated that mechanical factors including a reduction in subacromial space, scapular dyskinesia and different acromial shapes are unlikely directly contributing to RCRSP.

AIMS

Since the precise RCRSP pain mechanism remains unclear, the aim of this narrative review is to discuss possible sources of pain contributing to RCRSP according to the mechanisms-based pain classifications.

RESULTS AND DISCUSSION

Research findings on potential mechanical nociceptive factors of RCRSP are conflicting; investigations of neuropathic and central pain mechanisms of RCRSP are limited and inconclusive. Overall, available evidence has indicated moderate to strong correlations between RCRSP and chemical nociceptive sources of pain.

CONCLUSION

Results from current research may provide new directions for future studies on the aetiology of RCRSP and its clinical management towards a biochemical view instead of the traditional mechanical hypothesis.

Signs of Nervous System Sensitization in Female Runners with Chronic Patellofemoral Pain

Background

Patellofemoral pain (PFP) is a common overuse injury among runners, affecting females at a higher rate than males. PFP can often become chronic, with evidence suggesting it may be linked to both peripheral and central sensitization of the nervous system. Sensitization of the nervous system can be identified through quantitative sensory testing (QST).

Hypothesis/Purpose

The primary objective of this pilot study was to quantify and compare pain sensitivity as identified through QST measures, in active female runners with and without PFP.

Study Design

Cohort Study.

Methods

Twenty healthy female runners and 17 female runners with chronic PFP symptoms were enrolled. Subjects completed the Knee injury and Osteoarthritis Outcome Score for Patellofemoral Pain (KOOS-PF), University of Wisconsin Running Injury and Recovery Index (UWRI), and the Brief Pain Inventory (BPI). QST consisted of pressure pain threshold testing to three local and three distant sites to the knee, heat temporal summation, heat pain threshold, and conditioned pain modulation. Data was analyzed utilizing independent t-tests for comparison of between-group data, effect sizes for QST measures (Pearson's r), and Pearson's correlation coefficient between pressure pain threshold values at the knee and functional testing.

Results

The PFP group exhibited significantly lower scores on the KOOS-PF (p<0.001), BPI Pain Severity and Interference Scores (p<0.001), and UWRI (p<0.001). Primary hyperalgesia, identified through decreased pressure pain threshold at the knee, was detected in the PFP group at the central patella (p<0.001), lateral patellar retinaculum (p=0.003), and patellar tendon (p=0.006). Secondary hyperalgesia, a sign of central sensitization, was observed via differences in pressure pain threshold testing for the PFP group at the uninvolved knee (p=0.012 to p=0.042), involved extremity remote sites (p=0.001 to p=0.006), and uninvolved extremity remote sites (p=0.013 to p=0.021).

Conclusion

Compared to healthy controls, female runners with chronic PFP symptoms exhibit signs of both peripheral sensitization. Despite actively participating in running, nervous system sensitization may contribute to continued pain in these individuals. For female runners with chronic PFP, physical therapy management may need to include interventions which address signs of central and peripheral sensitization.

Level of Evidence

Level 3.

Biomechanics and lower limb function are altered in athletes and runners with achilles tendinopathy compared with healthy controls: A systematic review

Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of "medial collapse". Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.

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.

Lateral Elbow Pain and Muscle Function Impairments

Although often described as a self-limiting condition and likely to resolve on its own, high recurrence rates and extended sick leave frame a need for effective non-surgical treatment for people with lateral elbow tendinopathy. The interrelationship of histological and structural changes to the tendon, the associated impairments in motor control, and potential changes in pain processing may all drive symptoms. This clinical practice guideline covers the epidemiology, functional anatomy and pathophysiology, risk factors, clinical course, prognosis, differential diagnosis, tests and measures, and interventions for managing lateral elbow tendinopathy in the physical therapy clinic. J Orthop Sports Phys Ther 2022;52(12):CPG1-CPG111. doi:10.2519/jospt.2022.0302.

The effect of combined Action Observation Therapy with eccentric exercises in the treatment of mid-portion Achilles-tendinopathy: a feasibility pilot randomised controlled trial

BACKGROUND

Mid-portion Achilles Tendinopathy (AT) is a common musculoskeletal condition with varying rehabilitation success rates. Despite the prevalence of this condition, a considerable proportion of individuals experience persisting pain and functional deficits. Current treatment approaches bias the biomedical model which emphasises physically treating and loading the tendon. Overall, there is a lack of consideration for the central nervous system that is commonly implicated in chronic injuries. The aim of this pilot study was to explore the feasibility of combining Action Observation Therapy (AOT), a treatment technique which targets central changes and influences motor learning, with eccentric exercises in the treatment of mid-portion AT. AOT involves the observation of movements and is commonly followed by the physical performance of these same movements.

METHODOLOGY

This was a double-blinded randomised controlled pilot feasibility study. All participants underwent the 12-week Alfredson eccentric training protocol. The intervention group watched videos of the exercises prior to performing these exercises, whilst the control group watched nature videos before performing the same exercises. Study feasibility was the primary outcome measure, with the Victorian Institute of Sports Assessment- Achilles (VISA-A) selected as the primary clinical outcome measure.

RESULTS

Thirty participants were recruited, reflecting a 75% eligibility rate and 100% of eligible participants enrolled in the study. The retention rate at week 12 was 80%. At week six the mean VISA-A score improved by 18.1 (95% CI 10.2-26.0) in the intervention group and 7.7 (95% CI 0.3-14.9) in the control group, and 75% and 33% of participants in the intervention and control group respectively exceeded the minimal clinically important difference (MCID). At week 12 the mean VISA-A score from baseline improved by 22.25 (95% CI 12.52-31.98) in the intervention group and 16.5-(95% CI 8.47-24.53) in the control group, equating to 75% and 58% in each group respectively exceeding the MCID.

CONCLUSION

The positive feasibility outcomes and exploratory data from the clinical outcome measures suggest that a larger scaled RCT is warranted to further investigate the impact of AOT in the rehabilitation of mid-portion AT. Trial registration ISRCTN58161116, first registered on the 23/12/2020.

Autonomic Nervous System Function and Central Pain Processing in People With Frozen Shoulder: A Case-control Study

OBJECTIVES

The pathophysiology of a frozen shoulder (FS) is thought to be related to chronic inflammation. Chronic inflammation may disturb the immune system and consequently the nervous system as part of an overarching system. The aim of this study was to determine the presence of disturbed autonomic nervous system function and altered central pain processing (CPP) in patients with FS. Secondarily, the presence of psychological variables (catastrophizing and hypervigilance) and self-reported associated symptoms of altered CPP in patients with FS were investigated.

METHODS

Patients with FS and healthy controls completed the Composite Autonomic Symptom Score (autonomic function) and underwent quantitative sensory testing to assess tactile sensitivity (ie, allodynia), pressure pain thresholds (PPTs, ie, hyperalgesia), temporal summation of pain, and Conditioned Pain Modulation (CPM). Psychological issues were explored with the Pain Catastrophizing Scale and the Pain Vigilance and Awareness Questionnaire, and self-reported symptoms associated with altered CPP were determined with the Central Sensitization Inventory.

RESULTS

Thirty-two patients with FS and 35 healthy controls were analyzed in the study. Patients with FS showed more self-reported autonomic symptoms and symptoms of altered CPP, higher levels of pain catastrophizing and hypervigilance, and are more sensitive to tactile touches and mechanical pressure compared with controls.

DISCUSSION

On the basis of the effect sizes, between-group differences in allodynia, hyperalgesia, catastrophizing, and hypervigilance were clinically relevant, but only local allodynia, hyperalgesia, catastrophizing, and hypervigilance were statistically different. Therefore, obvious altered CPP was not present at the group level in patients with FS compared with controls.

In the Shoulder or in the Brain? Behavioral, Psychosocial and Cognitive Characteristics of Unilateral Chronic Shoulder Pain with Symptoms of Central Sensitization

The recognition of central sensitization (CS) is crucial, as it determines the results of rehabilitation. The aim of this study was to examine associations between CS and catastrophizing, functionality, disability, illness perceptions, kinesiophobia, anxiety, and depression in people with chronic shoulder pain (SP). In this cross-sectional study, 64 patients with unilateral chronic SP completed a few questionnaires including the Central Sensitization Inventory, the Oxford Shoulder Score, the Tampa Scale for Kinesiophobia, the Hospital Anxiety and Depression Scale, the Pain Catastrophizing Scale, the Brief Illness Perception Questionnaire and the “arm endurance” test. On the basis of three constructed linear regression models, it was found that pain catastrophizing and depression (model 1: p < 0.001, R = 0.57, R2 = 0.33), functionality (model 2: p < 0.001, R = 0.50, R2 = 0.25), and helplessness (model 3: p < 0.001, R = 0.53, R2 = 0.28) were significant predictors for CS symptoms in chronic SP. Two additional logistic regression models also showed that depression (model 4: p < 0.001, Nagelkerke R2 = 0.43, overall correct prediction 87.5%) and functionality (model 5: p < 0.001, Nagelkerke R2 = 0.26, overall correct prediction 84.4%) can significantly predict the classification of chronic SP as centrally sensitized. Patients who were classified as centrally sensitized (n = 10) were found to have significantly worse functionality, psychological factors (anxiety, depression, kinesiophobia, catastrophizing), and pain intensity (p < 0.05). Catastrophizing, depression, and functionality are predictive factors of CS symptoms in patients with chronic shoulder pain. Health care providers should adopt a precision medicine approach during assessment and a holistic rehabilitation of patients with unilateral chronic SP.

Biopsychosocial approach to tendinopathy

Tendinopathy describes a spectrum of changes that occur in damaged tendons, leading to pain and reduced function that remains extremely challenging for all clinicians. There is an increasing awareness of the influence that psychological and psychosocial components, such as self-efficacy and fear-avoidance, have on rehabilitation outcomes in musculoskeletal medicine. Although it is widely accepted that psychological/psychosocial factors exist in tendinopathy, there is currently a distinct lack of trials measuring how these factors affect clinical outcomes. Biopsychosocial treatments acknowledge and address the biological, psychological and social contributions to pain and disability are currently seen as the most efficacious approach to chronic pain. Addressing and modulating these factors are crucial in the pathway of personalised treatments in tendinopathy and offer a real opportunity to drive positive outcomes in patients. In this education review, we also provide the current evidence-based guidance on psychological and psychosocial developments in musculoskeletal medicine and how these may be translated to treating tendinopathy using a biopsychosocial model.

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.

Concepts of Entheseal Pain

Pain is the main symptom in entheseal diseases (enthesopathies) despite a paucity of nerve endings in the enthesis itself. Eicosanoids, cytokines, and neuropeptides released during inflammation and repeated nonphysiologic mechanical challenge not only stimulate or sensitize primary afferent neurons present in structures adjacent to the enthesis, but also trigger a "neurovascular invasion" that allows the spreading of nerves and blood vessels into the enthesis. Nociceptive pseudounipolar neurons support this process by releasing neurotransmitters from peripheral endings that induce neovascularization and peripheral pain sensitization. This process may explain the frequently observed dissociation between subjective symptoms such as pain and the structural findings on imaging in entheseal disease.

Nearly half of patients with chronic tendinopathy may have a neuropathic pain component, with significant differences seen between different tendon sites: a prospective cohort of more than 300 patients

Objectives

Identifying the prevalence of neuropathic pain components in patients with chronic tendinopathy conditions using the Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) questionnaire.

Methods

Patients with chronic tendinopathy and ‘tendon-like’ conditions treated within a single hospital outpatient clinic specialising in tendinopathy were identified. Pain scores, plus global function patient-reported outcome measures (5-Level version of EuroQol-5 Dimension and Musculoskeletal Health Questionnaire (MSK-HQ)), were completed and compared with the S-LANSS questionnaire

Results

341 suitable patients with chronic tendinopathy and potentially similar conditions were identified. Numbers: lateral elbow tendinopathy (39), greater trochanteric pain syndrome (GTPS; 112), patellar tendinopathy (11), non-insertional Achilles tendinopathy (40), insertional Achilles tendinopathy (39), plantar fasciopathy (100). 68% were female, with a mean age of 54.0±11.3 years and a mean symptom duration of 38.1±33.7 months.

There was a mean S-LANSS score of 11.4±6.4. Overall, 47% of patients scored 12 or greater points on S-LANSS, indicating the possible presence of neuropathic pain. The highest proportion was in patients with plantar fasciopathy (61%), the lowest in those with GTPS (33%). Weak correlations were found between the S-LANSS score and MSK-HQ score, the numerical rating scale (0–10) values for ‘average pain’ and for ‘worst pain’, but not with the MSK-HQ %health value.

Conclusion

S-LANSS identified nearly half of patients with chronic tendinopathy as possibly having a neuropathic pain component. This is of unclear clinical significance but worth further study to see if/how this may relate to treatment outcomes. These results are from a single hospital clinic dealing with patients with chronic tendinopathy, without a control group or those with shorter symptom duration. However, this reinforces the probability of neuropathic pain components in at least some patients with chronic tendinopathy.

Small extracellular vesicles from iPSC-derived mesenchymal stem cells ameliorate tendinopathy pain by inhibiting mast cell activation

Aim: This study aimed to explore the effect of small extracellular vesicles from induced pluripotent stem cell-derived mesenchymal stem cells (iMSC-sEVs) on acute pain and investigate the underlying mechanisms. Materials & methods: The pathology of tendons was accessed by hematoxylin and eosin staining, immunohistochemical and immunofluorescent staining. The pain degree was measured by pain-related behaviors. In vitro, we performed β-hexosaminidase release assay, RT-qPCR, toluidine blue staining, ELISA and RNA sequencing. Results: iMSC-sEVs effectively alleviated acute pain in tendinopathy as well as inhibiting activated mast cell infiltration and interactions with nerve fibers in vivo. In vitro, iMSC-sEVs reduced the degranulation of mast cells and the expression of proinflammatory cytokines and genes involved in the HIF-1 signaling pathway. Conclusion: This study demonstrated that iMSC-sEVs relieved tendinopathy-related pain through inhibiting mast cell activation via the HIF-1 signaling pathway.

Stop Using the Eccentric Exercises as the Gold Standard Treatment for the Management of Lateral Elbow Tendinopathy

The most common tendinopathy in the elbow area is the Lateral elbow tendinopathy (LET) [...].

Current understanding of the diagnosis and management of the tendinopathy: An update from the lab to the clinical practice

Tendinopathy is labeled by many authors as a troublesome, common pathology, present in up to 30% medical care consultations involving musculoskeletal conditions. Despite the lasting interest for addressing tendon pathology, current researchers agree that even the exact definition of the term tendinopathy is unclear. Tendinopathy is currently diagnosed as a clinical hypothesis based on the patient symptoms and physical context. One of the main goals of current clinical management is to personalize treatment approaches to adapt them to the many different needs of the population. Tendons are complex structures that unite muscles and bones with two main objectives: to transmit forces and storage and release energy. Regarding the tensile properties of the tendons, several authors argued that tendons have higher tensile strength compared with muscles, however, are considered less flexible. Tendinopathy is an accepted term which is used to indicated a variety of tissue conditions that appear in injured tendons and describes a non-rupture damage in the tendon or paratendon, which is intensified with mechanical loading Even when the pathoetiology of tendinopathy is unclear, there is a wide array of treatments available to treat and manage tendinopathy. Although tendinitis usually debuts with an inflammatory response, the majority of chronic tendinopathies do not present inflammation and so the choosing of treatment should vary depending on severity, compliance, pain and duration of symptoms. The purpose of this article is to review and provide an overview about the currently research of the tendon diagnosis, management and etiology.

Application of the 4-Element Movement System Model to Sports Physical Therapy Practice and Education

The 4-Element Movement System Model describes primary elements (motion, force, motor control, and energy) essential to the performance of all movements. The model provides a framework or scaffolding which allows for consistent processes to be used in examination and intervention decisions. The process starts with task identification followed by a systematic observation of control, amount, speed, symmetry, and symptoms during movement. Testable hypotheses are generated from the observations which inform the examination and the interventions. This commentary describes the use of the 4-Element Movement System Model in entry level and post-graduate residency educational programs and in clinical care with three common sports-related diagnoses.

LEVEL OF EVIDENCE

5.

Shoulder pain across more movements is not related to more rotator cuff tendon findings in people with chronic shoulder pain diagnosed with subacromial pain syndrome

Supplemental Digital Content is Available in the Text. Neither the number nor severity of rotator cuff tendons reported as abnormal was associated with the pain occurrence across clinically relevant arm movements.

Introduction:

People with chronic shoulder pain commonly report pain during arm movements in daily-life activities. Pain related to movement is commonly viewed as an accurate representation of tissue damage. Thus, when a person reports pain across a variety of movements, this is often understood as indicative of greater damage.

Objectives:

We aimed to investigate if movement-related pain that occurs across a wider variety of movements was associated with the number or severity of rotator cuff tendons reported as abnormal on a magnetic resonance imaging (MRI). To answer this question, this study was designed in 3 phases.

Methods:

We recruited 130 individuals with chronic shoulder pain diagnosed with subacromial pain syndrome. First, a list of daily functional activities commonly reported as painful by people with chronic shoulder pain was generated from 3 well-established outcome measures with 30 individuals and a measurement tool was developed with data from further 100 individuals, which demonstrated to have acceptable content validity, construct validity, internal consistency, interrater reliability, and structural validity. Multiple linear regression was then used to evaluate the hypotheses of the study. A direct acyclic graph was used to select variables for linear regression modelling.

Results:

There was no association between movement-related pain occurrence across movements and the MRI findings.

Conclusion:

Our study provides evidence that neither the number of rotator cuff tendons reported as abnormal nor the severity of each tendon imaging finding were associated with pain occurrence across movements and activities commonly perceived as painful by people with chronic shoulder pain.

Development of an optimised physiotherapist-led treatment protocol for lateral elbow tendinopathy: a consensus study using an online nominal group technique

OBJECTIVES

There are a wide range of physiotherapy treatment options for people with lateral elbow tendinopathy (LET); however, previous studies have reported inconsistent approaches to treatment and a lack of evidence demonstrating clinical effectiveness. This study aimed to combine the best available research evidence with stakeholder perspectives to develop key components of an optimised physiotherapist-led treatment protocol for testing in a future randomised controlled trial (RCT).

DESIGN

Online consensus groups using nominal group technique (NGT), a systematic approach to building consensus using structured multistage meetings.

SETTING

UK National Health Service (NHS).

PARTICIPANTS

10 physiotherapists with special interest in LET, 2 physiotherapy service managers and 3 patients who had experienced LET.

INTERVENTIONS

Two consensus groups were conducted; the first meeting focused on agreeing the types of interventions to be included in the optimised treatment protocol; the second meeting focused on specific details of intervention delivery. Participants were sent an evidence summary of available treatments for LET prior to the first meeting. All treatment options were discussed before anonymous voting and ranking of priority. Consensus for inclusion of each treatment option was set at ≥70% based on OMERACT guidelines. Options with 30%-69% agreement were discussed again, and a second vote was held, allowing for a change of opinion.

RESULTS

The optimised physiotherapist-led treatment package included: advice and education, exercise therapy and orthotics. Specific components for each of these interventions were also agreed such as: condition-specific advice, health-promotion advice, exercise types, exercise into 'acceptable' levels of pain, exercise dosage and type of orthoses. Other treatment options including electrotherapy, acupuncture and manual therapy were excluded.

CONCLUSION

An optimised physiotherapist-led treatment protocol for people with LET was successfully developed using an online NGT consensus approach. This intervention is now ready for testing in a future pilot/feasibility RCT to contribute much needed evidence about the treatment of LET.

TRIAL REGISTRATION NUMBER

This is the pre-cursor to the OPTimisE Pilot and Feasibility Randomised Controlled Trial. Registration: https://www.isrctn.com/ISRCTN64444585.

Runners with mid-portion Achilles tendinopathy have greater triceps surae intracortical inhibition than healthy controls

OBJECTIVES

This study aimed to investigate short-interval intracortical inhibition (SICI) and muscle function in the triceps surae of runners with mid-portion Achilles tendinopathy (AT).

METHODS

Runners with (n = 11) and without (n = 13) AT were recruited. Plantar flexor isometric peak torque and rate of torque development (RTD) were measured using an isokinetic dynamometer. Triceps surae endurance was measured as single-leg heel raise (SLHR) to failure test. SICI was assessed using paired-pulse transcranial magnetic stimulation during a sustained contraction at 10% of plantar flexor isometric peak torque.

RESULTS

Triceps surae SICI was 14.3% (95% CI: -2.1 to 26.4) higher in AT than in the control group (57.9%, 95% CI: 36.2 to 79.6; and 43.6% 95% CI: 16.2 to 71.1, p = 0.032) irrespective of the tested muscle. AT performed 16 (95% CI: 7.9 to 23.3, p < 0.001) fewer SLHR repetitions on the symptomatic side compared with controls, and 14 (95% CI: 5.8 to 22.0, p = 0.004), fewer SLHR repetitions on the non-symptomatic compared with controls. We found no between-groups differences in isometric peak torque (p = 0.971) or RTD (p = 0.815).

PERSPECTIVE

Our data suggest greater intracortical inhibition for the triceps surae muscles for the AT group accompanied by reduced SLHR endurance, without deficits in isometric peak torque or RTD. The increased SICI observed in the AT group could be negatively influencing triceps surae endurance; thus, rehabilitation aiming to reduce intracortical inhibition should be considered to improve patient outcomes. Furthermore, SLHR is a useful clinical tool to assess plantar flexor function in AT patients.

Two-point discrimination and judgment of laterality in individuals with chronic unilateral non-traumatic shoulder pain

BACKGROUND

Cortical representation of the painful body region may be disrupted in several chronic pain conditions. The two-point discrimination test (TPDT) and the Left/Right Judgement Task (LRJT) have been used to identify changes in the cortical body schema in several chronic pain conditions. However, it is unclear if these changes are present for all chronic pain mechanisms.

OBJECTIVES

To investigate the integrity of the body schema of the painful shoulder in patients with chronic unilateral nociceptive shoulder pain.

METHODS

The sample consisted of 52 individuals with chronic unilateral nociceptive shoulder pain. The TPDT was measured over the anterosuperior and lateral regions of both shoulders using a staircase method. Participants also performed judgment tests of shoulder and foot laterality. The comparison of the TPDT and LRJT was performed using the linear regression model with mixed effects.

RESULTS

There was no difference in TPDT in the anterosuperior and lateral regions when comparing the symptomatic and asymptomatic shoulders. There was no difference in the LRJT accuracy and response time between the symptomatic and asymptomatic shoulders. No differences were observed when comparing LRJT variables from symptomatic shoulder and foot.

CONCLUSION

Therefore, results do not provide clear evidence of altered body schema in chronic nociceptive unilateral shoulder pain. This suggest that alterations in body representations may depend on the primary pain mechanism.

Combined extracorporeal shockwave therapy and exercise for the treatment of tendinopathy: A narrative review

Tendinopathy is a chronic degenerative musculoskeletal disorder that is common in both athletes and the general population. Exercise and extracorporeal shockwave therapy (ESWT) is among the most common treatments used to mediate tendon healing and regeneration. The review presents the current understanding of mechanisms of action of ESWT and exercise in isolation and briefly synthesises evidence of their effectiveness for various tendinopathies. The central purpose of the review is to synthesize research findings investigating the combination of ESWT and exercise for five common tendinopathies (plantar heel pain, rotator cuff, lateral elbow, Achilles, and patellar tendinopathy) and provide recommendations on clinical applicability. Collectively, the available evidence indicates that ESWT combined with exercise in the form of eccentric training, tissue-specific stretching, or heavy slow resistance training are effective for specific tendinopathies and can therefore be recommended in treatment. Whilst there are at present a limited number of studies investigating combined EWST and exercise approaches, there is evidence to suggest that the combination improves outcomes in the treatment of plantar heel pain, Achilles, lateral elbow, and rotator cuff tendinopathy. However, despite overall positive outcomes in patellar tendinopathy, the combined treatment has not been shown at present to offer additional benefit over eccentric exercise alone.

Lateral epicondylosis: A literature review to link pathology and tendon function to tissue-level treatment and ergonomic interventions

BACKGROUND

Common treatments for lateral epicondylosis (LE) focus on tissue healing. Ergonomic advice is suggested broadly, but recommendations based on biomechanical motion parameters associated with functional activities are rarely made. This review analyzes the role of body functions and activities in LE and integrates the findings to suggest motion parameters applicable to education and interventions relevant to activities and life roles for patients.

PURPOSE

This study examines LE pathology, tendon and muscle biomechanics, and population exposure outlining potentially hazardous activities and integrates those to provide motion parameters for ergonomic interventions to treat or prevent LE. A disease model is discussed to align treatment approaches to the stage of LE tendinopathy.

STUDY DESIGN

Integrative review METHODS: We conducted in-depth searches using PubMed, Medline, and government websites. All levels of evidence were included, and the framework for behavioral research from the National Institutes of Health was used to synthesize ergonomic research.

RESULTS

The review broadened the diagnosis of LE from a tendon ailment to one affecting the enthesis of the capitellum. It reinforced the continuum of severity to encompass degeneration as well as regeneration. Systematic reviews confirmed the availability of evidence for tissue-based treatments, but evidence of well-defined harm reducing occupational interventions was scattered amongst evidence levels. Integration of biomechanical studies and population information gave insight into types of potentially hazardous activities and provided a theoretical basis for limiting hazardous exposures to wrist extensor tendons by reducing force, compression, and shearing during functional activities.

CONCLUSIONS

These findings may broaden the first treatment approach from a passive, watchful waiting into an active exploration and reduction of at-risk activities and motions. Including the findings into education modules may provide patients with the knowledge to lastingly reduce potentially hazardous motions during their daily activities, and researchers to define parameters of ergonomic interventions.

The analgesic effect of joint mobilization and manipulation in tendinopathy: a narrative review

Objective: To summarize the available literature with regards to the potential analgesic effect and mechanism of joint mobilization and manipulation in tendinopathy. Results: The effect of these techniques in rotator cuff tendinopathy and lateral elbow tendinopathy, applied alone, compared to a placebo intervention or along with other interventions has been reported in some randomized controlled trials which have been scrutinized in systematic reviews. Due to the small randomized controlled trials and other methodological limitations of the evidence base, including short-term follow-ups, small sample size and lack of homogenous samples further studies are needed. Literature in other tendinopathies such as medial elbow tendinopathy, de Quervain's disease and Achilles tendinopathy is limited since the analgesic effect of these techniques has been identified in few case series and reports. Therefore, the low methodological quality renders caution in the generalization of findings in clinical practice. Studies on the analgesic mechanism of these techniques highlight the activation of the descending inhibitory pain mechanism and sympathoexcitation although this area needs further investigation. Conclusion: Study suggests that joint mobilization and manipulation may be a potential contributor in the management of tendinopathy as a pre-conditioning process prior to formal exercise loading rehabilitation or other proven effective treatment approaches.

Evidence of Widespread Mechanical Hyperalgesia but Not Exercise-Induced Analgesia in Athletes With Mild Patellar Tendinopathy Compared With Pain-Free Matched Controls: A Blinded Exploratory Study

OBJECTIVE

The aim of the study was to assess centrally induced pain processing with pressure pain thresholds bilaterally and remotely in active volleyball and basketball athletes with mild patellar tendinopathy compared with asymptomatic control athletes. Secondary objective was to explore the role of exercise-induced analgesia during a training session in athletes with patellar tendinopathy.

DESIGN

In this exploratory study, pressure pain thresholds of 21 patellar tendinopathy athletes and 16 age- and sex-matched asymptomatic team members were measured by a blinded assessor bilaterally on the patellar tendon and unilaterally on the elbow extensor tendon with a pressure algometer before, during, and after a regular training session.

RESULTS

Patellar tendinopathy athletes had a significantly higher average body mass index compared with asymptomatic athletes (mean difference 1.75 kg/m2; 95% confidence interval = 0.35-3.15, P = 0.02). At baseline, athletes with patellar tendinopathy showed lowered pressure pain thresholds in the affected knee (P = 0.001), unaffected knee (P < 0.001), and elbow (P = 0.01) compared with controls. No clear patterns were identified to explain between-group differences in pressure pain thresholds before, during, and after exercise.

CONCLUSIONS

This exploratory study found primary and secondary mechanical hyperalgesia in athletes with patellar tendinopathy compared with asymptomatic athletes. Further research is required on the effects of an acute exercise bout on pain thresholds in this population.

Autoregulation in Resistance Training for Lower Limb Tendinopathy: A Potential Method for Addressing Individual Factors, Intervention Issues, and Inadequate Outcomes

Musculoskeletal disorders, such as tendinopathy, are placing an increasing burden on society and health systems. Tendinopathy accounts for up to 30% of musculoskeletal disorders, with a high incidence in athletes and the general population. Although resistance training has shown short-term effectiveness in the treatment of lower limb tendinopathy, more comprehensive exercise protocols and progression methods are required due to poor long-term outcomes. The most common resistance training protocols are predetermined and standardized, which presents significant limitations. Current standardized protocols do not adhere to scientific resistance training principles, consider individual factors, or take the importance of individualized training into account. Resistance training programs in case of tendinopathy are currently not achieving the required intensity and dosage, leading to high recurrence rates. Therefore, better methods for individualizing and progressing resistance training are required to improve outcomes. One potential method is autoregulation, which allows individuals to progress training at their own rate, taking individual factors into account. Despite the finding of their effectiveness in increasing the strength of healthy athletes, autoregulation methods have not been investigated in case of tendinopathy. The purpose of this narrative review was 3-fold: firstly, to give an overview and a critical analysis of the individual factors involved in tendinopathy and current resistance training protocols and their limitations. Secondly, to give an overview of the history, methods, and application of autoregulation strategies both in sports performance and physiotherapy. Finally, a theoretical adaptation of a current tendinopathy resistance training protocol using autoregulation methods is presented, providing an example of how the method could be implemented in clinical practice or future research.

High Rate of Pain Sensitization in Musculoskeletal Shoulder Diseases: A Systematic Review and Meta-analysis

BACKGROUND

Pain sensitization, defined as an increased responsiveness of nociceptive neurons to normal input, is detected in several musculoskeletal diseases, but there are no systematic reviews or meta-analyses about pain sensitization in shoulder pain.

OBJECTIVES

The aim of the study was to document pain sensitization rate and its impact in patients with shoulder pain.

MATERIALS AND METHODS

PubMed, Cochrane Library, and Web of Science were searched on January 8, 2020. Level I-IV studies, evaluating pain sensitization in musculoskeletal shoulder disorders through validated methods (questionnaires/algometry) were included. The primary outcome was pain sensitization rate. Secondary outcomes were the pain sensitivity level measured as pressure pain threshold, temporal summation, conditioned pain modulation, and suprathreshold heat pain response. Associated demographic and psychosocial factors were evaluated.

RESULTS

The rate of abnormal pressure pain threshold in patients with shoulder pain varied from 29% to 77%. Questionnaires detected pain sensitization in 11% to 24% of patients. This meta-analysis showed no difference in pressure pain threshold and central pain modulation but documented a significant difference in terms of suprathreshold heat pain response, indicating a hypersensitivity state in patients with shoulder pain versus asymptomatic controls. The only factor that was constantly found to correlate with higher sensitivity was a lower postoperative outcome.

DISCUSSION

Pain sensitization has a high rate among patients with musculoskeletal shoulder pain, regardless of the specific etiology, and this may lead to worse clinical outcome after treatment of the primary disease. The best way to assess pain sensitization still needs to be identified as the assessment methods results in used high variability in the documented pain sensitization rate.

DIAGNOSIS OF THE ACHILLES INSERTIONAL TENDINOPATHIES BY ALGOMETRY

INTRODUCTION

Diagnosis of Achilles insertional tendinopathies (AIT) is based on pain by tendon palpation. However, there is no consensus or standard regarding the amount of force to be used during the evaluation. The algometry is a method of measuring the pressure applied in a specific region and can be a method for determining diagnosis values.

GOAL

To determine a cut-off value for Pain Threshold (PT) in the assessment of AIT.

DESIGN

This is a prospective case-control study of diagnostic accuracy, to develop a diagnostic criterion.

METHODS

Forty asymptomatic individuals and forty patients with insertional Achilles tendinopathy, matched by age and sex, were evaluated, and submitted to algometry for PT and for Visual Analogical Scale (VAS) levels with 3 kg/f at the insertion of the calcaneal tendon by two different evaluators. Inter-observer reproducibility was accessed through the interclass correlation index (ICC). Sensitivity and specificity calculation of PT and of VAS ​​were calculated and plotted on a ROC (Receiver Operator Characteristic) curve.

RESULTS

The lowest ICC found was 0.788. Regarding the diagnosis through TP, the 4.08 kg/f mark showed the best relation between sensitivity and specificity (92.5% and 92.5%, respectively). Algometry values lower than 4.08 were considered positive for disease. For the diagnosis of TIA through VAS with 3 kg/f, the value of 2.98 was determined (sensitivity of 92.5% and specificity of 97.5%).

CONCLUSION

The algometry showed to be a simple and reliable method for diagnosing AIT. Values for PT under 4.08 kg/f were found predictors of the disease.

Left/right discrimination is not impaired in people with unilateral chronic Achilles tendinopathy

OBJECTIVE

Impaired left/right discrimination of an affected body part has been observed in various chronic pain states. This study aimed to examine whether people with unilateral chronic Achilles tendinopathy also present with impaired left/right discrimination.

DESIGN

Cross-sectional study.

METHODS

Nineteen runners with persistent unilateral Achilles tendinopathy and 19 matched healthy volunteers performed a left/right discrimination task in a laboratory setting. Participants were shown pictures of feet, hands and Shepard-Metzler figures and were asked to decide as accurately and as fast as possible whether the body part belonged to the left or right side of the body, or whether the Shepard-Metzler figures were rotated or mirrored. Performance was evaluated in terms of accuracy and response time. Data were analysed with mixed-design ANOVAs.

RESULTS

The decline in left/right discrimination ability at group level, if present, between affected and unaffected side, or compared to healthy participants, was negligible for both accuracy (<1.5%) and response time (<50 ms). There was no significant effect of side (affected versus unaffected side) or group (people with Achilles tendinopathy versus healthy) for accuracy (p > 0.36) or response time (p > 0.69).

CONCLUSIONS

People with Achilles tendinopathy recognised the affected side as accurately and as fast as the non-affected side and their performance was comparable to healthy participants. The absence of impaired left/right discrimination despite the chronicity of the condition may be attributable to the typical intermittent nature of Achilles tendinopathy pain and/or maintained sports activity.

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.

Nociplastic Pain Criteria or Recognition of Central Sensitization? Pain Phenotyping in the Past, Present and Future

Recently, the International Association for the Study of Pain (IASP) released clinical criteria and a grading system for nociplastic pain affecting the musculoskeletal system. These criteria replaced the 2014 clinical criteria for predominant central sensitization (CS) pain and accounted for clinicians' need to identify (early) and correctly classify patients having chronic pain according to the pain phenotype. Still, clinicians and researchers can become confused by the multitude of terms and the variety of clinical criteria available. Therefore, this paper aims at (1) providing an overview of what preceded the IASP criteria for nociplastic pain ('the past'); (2) explaining the new IASP criteria for nociplastic pain in comparison with the 2014 clinical criteria for predominant CS pain ('the present'); and (3) highlighting key areas for future implementation and research work in this area ('the future'). It is explained that the 2021 IASP clinical criteria for nociplastic pain are in line with the 2014 clinical criteria for predominant CS pain but are more robust, comprehensive, better developed and hold more potential. Therefore, the 2021 IASP clinical criteria for nociplastic pain are important steps towards precision pain medicine, yet studies examining the clinimetric and psychometric properties of the criteria are urgently needed.

Current concepts in the rehabilitation of rotator cuff related disorders

Rotator cuff related disorders (RCRD) are common. Exercise-based rehabilitation can improve outcomes, yet uncertainty exists regarding the characteristics of these exercises. This scoping review paper summarises the key characteristics of the exercise-based rehabilitation of rotator cuff related disorders (RCRD). An iterative search process was used to capture the breadth of current evidence and a narrative summary of the data was produced. 57 papers were included. Disagreement around terminology, diagnostic standards, and outcome measures limits the comparison of the data. Rehabilitation should utilise a biopsychosocial approach, be person-centred and foster self-efficacy. Biomedically framed beliefs can create barriers to rehabilitation. Pain drivers in RCRSD are unclear, as is the influence of pain during exercise on outcomes. Expectations and preferences around pain levels should be discussed to allow the co-creation of a programme that is tolerated and therefore engaged with. The optimal parameters of exercise-based rehabilitation remain unclear; however, programmes should be individualised and progressive, with a minimum duration of 12 weeks. Supervised or home-based exercises are equally effective. Following rotator cuff repair, rehabilitation should be milestone-driven and individualised; communication across the MDT is essential. For individuals with massive rotator cuff tears, the anterior deltoid programme is a useful starting point and should be supplemented by functional rehabilitation, exercises to optimise any remaining cuff and the rest of the kinetic chain. In conclusion, exercise-based rehabilitation improves outcomes for individuals with a range of RCRD. The optimal parameters of these exercises remain unclear. Variation exists across current physiotherapy practice and post-operative rehabilitation protocols, reflecting the wide-ranging spectrum of individuals presenting with RCRD. Clinicians should use their communication and rehabilitation expertise to plan an exercise-based program in conjunction with the individual with RCRSD, which is regularly reviewed and adjusted.

Local hyperalgesia, normal endogenous modulation with pain report beyond its origin: a pilot study prompting further exploration into plantar fasciopathy

Background and aims Persistent tendinopathies were previously considered solely as peripheral conditions affecting the local tendinous tissue until quantitative sensory testing identified involvement of altered pain processing. In similar fashion, pain in patients with persistent plantar fasciopathy may also involve more than local tissue. The aim of this pilot study was to investigate potential differences in conditioned pain modulation and pressure and thermal pain thresholds, between individuals with PF and healthy pain-free controls, as a precursor to a larger-scale study. Methods We assessed 16 individuals with plantar fasciopathy and 11 pain-free controls. Plantar fasciopathy diagnosis was: palpation pain of the medial calcaneal tubercle or the proximal plantar fascia, duration ≥3 months, pain intensity ≥2/10, and ultrasound-measured plantar fascia thickness ≥4 mm. Quantitative sensory tests were performed locally at the plantar heel and remotely on the ipsilateral elbow. Assessments included pain thresholds for pressure, heat and cold, and conditioned pain modulation measured as change in local resting pressure pain threshold with cold water hand immersion. Participants rated pain intensity at pain threshold. Additionally, the area and distribution of plantar fasciopathy pain was drawn on a digital body chart of the lower limbs. Descriptive analyses were performed and between-group differences/effects expressed as standardised mean differences (d). Results There was no conditioned pain modulation difference between participants with plantar fasciopathy and controls (d = 0.1). Largest effects were on local pressure pain threshold and reported pain intensity on pressure pain threshold (d > 1.8) followed by pain intensity for heat and cold pain thresholds (d = 0.3-1.5). According to the digital body chart, pain area extended beyond the plantar heel. Conclusions The unlikelihood of a difference in conditioned pain modulation yet a pain area extending beyond the plantar heel provide a basis for exploring altered pain processing in a larger-scale study. Implications This was the first study to investigate the presence of altered pain processing in individuals with plantar fasciopathy using a conditioned pain modulation paradigm and thermal pain thresholds. We found no indication of an altered pain processing based on these measures, however, patients rated pain higher on thresholds compared to controls which may be important to clinical practice and warrants further exploration in the future.

Individuals with Persistent Greater Trochanteric Pain Syndrome Exhibit Impaired Pain Modulation, as well as Poorer Physical and Psychological Health, Compared with Pain-Free Individuals: A Cross-Sectional Study

OBJECTIVES

To compare physical, sensory, and psychosocial factors between individuals with greater trochanteric pain syndrome and controls and to explore factors associated with pain and disability.

DESIGN

Cross-sectional study.

SETTING

General community.

SUBJECTS

Patients with persistent, clinically diagnosed greater trochanteric pain syndrome and healthy controls.

METHODS

Participants completed tests of thermal and pressure pain threshold, conditioned pain modulation, temporal summation, muscle strength, physical function, physical activity, psychological factors, and health-related quality of life. Standardized mean differences between groups were calculated, and multiple linear regression identified factors associated with pain and disability.

RESULTS

Forty patients (95% female, average [SD] age = 51 [9] years) and 58 controls (95% female, average [SD] age = 53 [11] years) were included. Heat pain threshold, temporal summation, and pain catastrophizing were not different between groups. Compared with controls, patients displayed significantly poorer quality of life (standardized mean difference = -2.66), lower pressure pain threshold locally (-1.47, remotely = -0.57), poorer health status (-1.22), impaired physical function (range = 0.64-1.20), less conditioned pain modulation (-1.01), weaker hip abductor/extensor strength (-1.01 and -0.59), higher depression (0.72) and anxiety (0.61) levels, lower cold pain threshold locally (-0.47, remotely = -0.39), and less time spent in (vigorous) physical activity (range = -0.43 to -0.39). Twenty-six percent of pain and disability was explained by depression, hip abductor strength, and time to complete stairs.

CONCLUSIONS

Patients with greater trochanteric pain syndrome exhibited poorer health-related quality of life, physical impairments, widespread hyperalgesia, and greater psychological distress than healthy controls. Physical and psychological factors were associated with pain and disability.

Central Sensitization in Chronic Musculoskeletal Pain Disorders in Different Populations: A Cross-Sectional Study

OBJECTIVE

Chronic musculoskeletal pain disorders (CMPDs) are among the leading causes of disabilities across populations, resulting in high social and financial burden. This persistent pain condition may include the central sensitization (CS) phenomenon, which implies a wide range of symptoms and that may be taken into account in CMPD treatment. CS symptoms can be measured by the Central Sensitization Inventory (CSI). The aims of the study were to describe CS symptoms in patients suffering from several CMPDs and to analyze differences due to gender, age, and body mass index (BMI).

DESIGN

This cross-sectional study recruited a total of 395 Spanish participants suffering from several CMPDs.

SETTING

CS symptoms were measured with the Spanish Version of the CSI. The total score (0-100) and a cutoff score of 40 were recorded.

SUBJECTS

A total of 395 participants were included.

RESULTS

The mean CSI total score for the whole sample was 24.6 ± 12.0 points. CSI total score had subclinical values in the whole sample, whereas participants with scores >40 were found across different CMPDs, such as low back pain (37.8%) and neck pain (32.4%); 14.6% of females and 1.7% of males presented CSI scores >40. Patients showed significant differences in CSI cutoff point by gender (P = 0.010) and CSI total score by age (P = 0.014).

CONCLUSIONS

Given the high prevalence of clinically relevant CSI scores (>40) in people with a CMPD, especially low back pain and neck pain, we recommend that clinicians supplement their assessment with the CSI for improved decision-making during treatment.

A Novel Biopsychosocial Approach to Neck Pain in Military Helicopter Aircrew

INTRODUCTION: Flight-related neck pain (FRNP) is a frequently reported musculoskeletal complaint among military helicopter aircrew. However, despite its prevalence and suspected causes, little is known of the underpinning pain mechanisms or the impact of neck pain on aircrews in-flight task performance. The biopsychosocial (BPS) approach to health, combined with the contemporary conceptualization of musculoskeletal pain, in which injury and pain are not necessarily synonymous, provides a relatively new holistic framework within which to consider the problem of FRNP in military helicopter aircrew. Combining these concepts, a new conceptual model is proposed to illustrate how biopsychosocial factors may influence pain perception, potentially affecting aircrews capacity to process information and, therefore, threatening in-flight task performance. Recommendations are made for considering the underlying pain mechanisms of FRNP to aid prognoses and guide the development of holistic evidence-based countermeasures for FRNP in military helicopter aircrew. Development of instruments able to measure psychosocial factors, such as self-efficacy and functional ability, validated in the military helicopter aircrew population, would assist this task.Vail RE, Harridge SDR, Hodkinson PD, Green NDC, Pavlou M. A novel biopsychosocial approach to neck pain in military helicopter aircrew. Aerosp Med Hum Perform. 2021; 92(5):333341.

Central sensitisation in chronic pain conditions: latest discoveries and their potential for precision medicine

Chronic pain is a leading cause of disability globally and associated with enormous health-care costs. The discrepancy between the extent of tissue damage and the magnitude of pain, disability, and associated symptoms represents a diagnostic challenge for rheumatology specialists. Central sensitisation, defined as an amplification of neural signalling within the CNS that elicits pain hypersensitivity, has been investigated as a reason for this discrepancy. Features of central sensitisation have been documented in various pain conditions common in rheumatology practice, including fibromyalgia, osteoarthritis, rheumatoid arthritis, Ehlers-Danlos syndrome, upper extremity tendinopathies, headache, and spinal pain. Within individual pain conditions, there is substantial variation among patients in terms of presence and magnitude of central sensitisation, stressing the importance of individual assessment. Central sensitisation predicts poor treatment outcomes in multiple patient populations. The available evidence supports various pharmacological and non-pharmacological strategies to reduce central sensitisation and to improve patient outcomes in several conditions commonly seen in rheumatology practice. These data open up new treatment perspectives, with the possibility for precision pain medicine treatment according to pain phenotyping as a logical next step. With this view, studies suggest the possibility of matching non-pharmacological approaches, or medications, or both to the central sensitisation pain phenotypes.

The utilization and effects of filiform dry needling in the management of tendinopathy: a systematic review

Background: Tendinopathy is frequently associated with pain, soft tissue impairments and muscle performance limitations. Dry needling (DN) incorporates a fine filiform needle to penetrate the skin and underlying soft tissue in an effort to decrease pain and improve function. While injectable interventions and gauged-needle tendon fenestration for tendinopathy has been reviewed, DN for tendinopathy has yet to be synthesized.Objective: To systematically review the utilization and effects of DN for tendinopathy.Methods: Six electronic databases (PubMed, CINAHL, Scopus, SportDiscus, PEDro and the Cochrane Library) were searched from inception through August 15, 2020, using appropriate keywords and relevant synonyms.Results: After screening 462 articles, 10 studies met inclusion criteria. Study designs included case reports, case series, and randomized clinical trials. DN was used in isolation in 3/10 studies and as part of a multimodal approach in 7/10 studies. DN was associated with improved pain, function, muscle performance and perceived improvement in each study evaluating the relevant outcome. Conflicting results were found in comparative studies evaluating DN.Conclusions: DN may be a useful adjunctive treatment in the conservative management of tendinopathy, although its discrete effect is unclear. Very Low-quality evidence and methodological limitations suggest further investigation is warranted.

Are pain coping strategies and neuropathic pain associated with a worse outcome after conservative treatment for Achilles tendinopathy? A prospective cohort study

OBJECTIVES

To analyse whether (1) passive or active pain coping strategies and (2) presence of neuropathic pain component influences the change of Achilles tendinopathy (AT) symptoms over a course of 24 weeks in conservatively-treated patients.

DESIGN

Prospective cohort study.

METHODS

Patients with clinically-diagnosed chronic midportion AT were conservatively treated. At baseline, the Pain Coping Inventory (PCI) was used to determine scores of coping, which consisted of two domains, active and passive (score ranging from 0 to 1; the higher, the more active or passive). Presence of neuropathic pain (PainDETECT questionnaire, -1 to 38 points) was categorized as (a) unlikely (≤12 points), (b) unclear (13-18 points) and (c) likely (≥19 points). The symptom severity was determined with the validated Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire (0-100) at baseline, 6, 12 and 24 weeks. We analysed the correlation between (1) PCI and (2) PainDETECT baseline scores with change in VISA-A score using an adjusted Generalized Estimating Equations model.

RESULTS

Of 80 included patients, 76 (95%) completed the 24-weeks follow-up. The mean VISA-A score (standard deviation) increased from 43 (16) points at baseline to 63 (23) points at 24 weeks. Patients had a mean (standard deviation) active coping score of 0.53 (0.13) and a passive score of 0.43 (0.10). Twelve patients (15%) had a likely neuropathic pain component. Active and passive coping mechanisms and presence of neuropathic pain did not influence the change in AT symptoms (p=0.459, p=0.478 and p=0.420, respectively).

CONCLUSIONS

Contrary to widespread belief, coping strategy and presence of neuropathic pain are not associated with a worse clinical outcome in this homogeneous group of patients with clinically diagnosed AT.

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.