Contralateral mechanical hyperalgesia and altered pain modulation in men who have unilateral insertional Achilles tendinopathy: A cross-sectional study

Endogenous pain modulation is not different in basketball or volleyball athletes with patellar tendinopathy compared to asymptomatic athletic controls

BACKGROUND

Patellar tendinopathy is highly prevalent in basketball and volleyball athletes. Despite pain being the main symptom reported, underlying mechanisms are unclear.

OBJECTIVES

Our primary aim was to compare endogenous pain inhibition using a conditioned pain modulation protocol in basketball and volleyball athletes with patellar tendinopathy to asymptomatic athletic controls. Our secondary aim was to compare endogenous pain facilitation using a temporal summation protocol.

DESIGN

Cross-sectional case-control.

METHODS

Twenty-six athletes and 19 asymptomatic controls participated. We calculated the difference in PPT at the patellar tendon over the most painful site (pain site), the ipsilateral tibialis anterior (regional site), and the contralateral elbow lateral epicondyle (remote site), before and after immersion of the hand (ipsilateral to pain site) in painful cold-water. PPT change was used to quantify endogenous pain inhibition. Participants rated pain on a numerical rating scale (NRS; 0 = no pain to 10 = worst pain imaginable) at five, 20, 60 and 120 s during the cold-water immersion task. Change in NRS from five to 20 s quantified temporal summation.

RESULTS

Median symptom duration in our patellar tendinopathy group was 39 (IQR 22.5-55.5) months, and 85% experienced symptoms bilaterally. We did not observe alterations in endogenous pain inhibition at any site, or in temporal summation, in athletes with patellar tendinopathy compared to controls (p > 0.05).

CONCLUSION

Our findings indicate that altered central nervous system function is not a predominate feature contributing to pain in jumping athletes with patellar tendinopathy. Accordingly, clinicians should view pain as being of a local tissue source if targeting this symptom.

Does shockwave therapy lead to better pain and function than sham over 12 weeks in people with insertional Achilles tendinopathy? A randomised controlled trial

OBJECTIVES

To investigate the efficacy of adding radial extracorporeal shockwave therapy or sham to exercise for people with insertional Achilles tendinopathy.

DESIGN

A two-armed, parallel-group, explanatory, single-centre, randomised controlled trial within a superiority framework.

SETTING

Private clinic.

PARTICIPANTS

People diagnosed with insertional Achilles tendinopathy who were over 18 years old with a symptom duration of greater than 3 months.

INTERVENTION

A total of 76 people were randomly assigned (one-to-one ratio) to receive three sessions of radial extracorporeal shockwave therapy or sham to the affected side (or most affected side if bilateral). All participants received identical education and exercise.

OUTCOME MEASURES

The primary outcome was the Victorian Institute of Sports Assessment - Achilles questionnaire. Measures were recorded at baseline, 6 weeks and 12 weeks.

RESULTS

At 12 weeks, the questionnaire data were available for 37 people (96%) in the radial extracorporeal shockwave therapy group and 36 people (95%) in the sham group. For the primary outcome, we found no evidence for between-group differences at 6 (3, 95% confidence interval -4.6-10.5) or 12 weeks (4.6, 95% confidence interval -2.5-11.6). There was also no evidence for a between-group difference for any secondary outcome measures at either 6 or 12 weeks (p > .05). No serious adverse events were reported.

CONCLUSION

The addition of radial extracorporeal shockwave therapy to exercise and education did not lead to improvements in pain, function or other outcomes compared to sham at 6 or 12 weeks among people with insertional Achilles tendinopathy.ANZCTR Reg No: ACTRN12620000035921.

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

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

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.

What Do We Know about Nociplastic Pain?

Nociplastic pain is a recently distinguished type of pain, distinct from neuropathic and nociceptive pain, and is well described in the literature. It is often mistaken for central sensitization. Pathophysiology has not been clearly established with regard to alteration of the concentration of spinal fluid elements, the structure of the white and gray matter of the brain, and psychological aspects. Many different diagnostic tools, i.e., the painDETECT and Douleur Neuropathique 4 questionnaires, have been developed to diagnose neuropathic pain, but they can also be applied for nociplastic pain; however, more standardized instruments are still needed in order to assess its occurrence and clinical presentation. Numerous studies have shown that nociplastic pain is present in many different diseases such as fibromyalgia, complex regional pain syndrome type 1, and irritable bowel syndrome. Current pharmacological and nonpharmacological treatments for nociceptive and neuropathic pain are not entirely suitable for treating nociplastic pain. There is an ongoing effort to establish the most efficient way to manage it. The significance of this field has led to several clinical trials being carried out in a short time. The aim of this narrative review was to discuss the currently available evidence on pathophysiology, associated diseases, treatment possibilities, and clinical trials. It is important that physicians widely discuss and acknowledge this relatively new concept in order to provide optimized pain control for patients.

Evidence for Improvement in Local but Not Diffuse Pressure Pain Thresholds Following Physical Therapist Interventions for Tendinopathy: A Systematic Review

OBJECTIVES

The objectives of this study were to investigate whether quantitative sensory testing proxy measures for peripheral and central sensitization change following physical therapist interventions for tendinopathy and whether changes occur in parallel to changes in self-reported pain.

METHODS

Four databases-Ovid EMBASE, Ovid MEDLINE, CINAHL Plus, and CENTRAL-were searched from inception to October 2021. Three reviewers extracted data for the population, tendinopathy, sample size, outcome, and physical therapist intervention. Studies that reported quantitative sensory testing proxy measures and pain at baseline and another time point following a physical therapist intervention were included. Risk of bias was assessed using the Cochrane Collaboration's tools and the Joanna Briggs Institute checklist. Levels of evidence were assessed using the Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

Twenty-one studies were included and all investigated changes in pressure pain threshold (PPT) at either local and/or diffuse sites. Change in other proxy measures of peripheral and central sensitization were not investigated among any studies. Diffuse PPT did not demonstrate significant change in all trial arms that reported this outcome. Local PPT improved for 52% of trial arms, and it was more likely to change at the medium (63%) and longer (100%) compared with the immediate (36%) and short (50%) timepoints. On average, 48% of trial arms demonstrated parallel changes in either outcome. Pain improvement was more frequent than local PPT improvement at all timepoints except for the longest.

CONCLUSION

Local PPT may improve among people receiving physical therapist interventions for tendinopathy, but these changes appear to lag behind changes in pain. Change in diffuse PPT among people with tendinopathy has been infrequently investigated in the literature.

IMPACT

The findings of the review contribute to knowledge of how tendinopathy pain and PPT change with treatments.

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.

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.

ICON 2020-International Scientific Tendinopathy Symposium Consensus: A Systematic Review of Outcome Measures Reported in Clinical Trials of Achilles Tendinopathy

BACKGROUND

Nine core domains for tendinopathy have been identified. For Achilles tendinopathy there is large variation in outcome measures used, and how these fit into the core domains has not been investigated.

OBJECTIVE

To identify all available outcome measures outcome measures used to assess the clinical phenotype of Achilles tendinopathy in prospective studies and to map the outcomes measures into predefined health-related core domains.

DESIGN

Systematic review.

DATA SOURCES

Embase, MEDLINE (Ovid), Web of Science, CINAHL, The Cochrane Library, SPORTDiscus and Google Scholar.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Clinical diagnosis of Achilles tendinopathy, sample size ≥ ten participants, age ≥ 16 years, and the study design was a randomized or non-randomized clinical trial, observational cohort, single-arm intervention, or case series.

RESULTS

9376 studies were initially screened and 307 studies were finally included, totaling 13,248 participants. There were 233 (177 core domain) different outcome measures identified across all domains. For each core domain outcome measures were identified, with a range between 8 and 35 unique outcome measures utilized for each domain. The proportion of studies that included outcomes for predefined core domains ranged from 4% for the psychological factors domain to 72% for the disability domain.

CONCLUSION

233 unique outcome measures for Achilles tendinopathy were identified. Most frequently, outcome measures were used within the disability domain. Outcome measures assessing psychological factors were scarcely used. The next step in developing a core outcome set for Achilles tendinopathy is to engage patients, clinicians and researchers to reach consensus on key outcomes measures.

PROSPERO REGISTRATION

CRD42020156763.