Mechanistic pain profiling in young adolescents with patellofemoral pain before and after treatment: a prospective cohort study

Bullying Involvement and Physical Pain Between Ages 10 and 13 Years: Reported History and Quantitative Sensory Testing in a Population-Based Cohort

We aimed to quantify the prospective association between bullying and physical pain in a population-based cohort of adolescents. We assessed 4,049 participants of the 10 and 13 years waves of the Generation XXI birth cohort study in Portugal. Pain history was collected using the Luebeck pain screening questionnaire. A subsample of 1,727 adolescents underwent computerized cuff pressure algometry to estimate pain detection/tolerance thresholds, temporal pain summation and conditioned pain modulation. Participants completed the Bully Scale Survey and were classified as "victim only", "both victim and aggressor", "aggressor only", or "not involved". Associations were quantified using Poisson or linear regression, adjusted for sex and adverse childhood experiences. When compared to adolescents "not involved", participants classified as "victim only" or "both victim and aggressor" at age 10 had higher risk of pain with psychosocial triggers, pain that led to skipping leisure activities, multisite pain, pain of higher intensity, and pain of longer duration, with relative risks between 1.21 (95% confidence interval: .99, 1.49) and 2.17 (1.57, 3.01). "Victims only" at age 10 had lower average pain detection and tolerance thresholds at 13 years (linear regression coefficients: -1.81 [-3.29, -.33] and -2.73 [-5.17, -.29] kPa, respectively), as well as higher pain intensity ratings (.37 [.07, .68] and .39 [.06, .72] mm), when compared with adolescents not involved. No differences were seen for the remaining bullying profiles or sensory measures. Our findings suggest that bullying may have long-term influence on the risk of chronic musculoskeletal pain and may interfere with responses to painful stimuli. PERSPECTIVE: We found prospective evidence that bullying victimization in youth: 1) is more likely to lead to negative reported pain experiences than the reverse, 2) may have long-term influence on adverse pain experiences, and 3) may contribute to pain phenotypes partly by interfering with somatosensory responses to painful stimuli.

Pain history and experimental pressure pain responses in adolescents: Results from a population-based birth cohort

BACKGROUND

Sensitized pain mechanisms are often reported in musculoskeletal pain conditions, but population-based paediatric studies are lacking. We assessed whether adolescents with musculoskeletal pain history had evidence of increased responsiveness to experimental pressure stimuli.

METHODS

Data were from 1496 adolescents of the Generation XXI birth cohort. Pain history was collected using the Luebeck Pain Questionnaire (self-reported at 13, parent-reported at 7 and 10 years). Two case definitions for musculoskeletal pain were considered: (1) cross-sectional-musculoskeletal pain lasting more than 3 months at age 13 and (2) longitudinal-musculoskeletal pain at age 13 with musculoskeletal pain reports at ages 7 and/or 10. Lower limb cuff pressure algometry was used to assess pain detection and tolerance thresholds, conditioned pain modulation effects (CPM, changes in thresholds in the presence on painful conditioning) and temporal summation of pain effects (TSP, changes in pain intensity to 10 phasic painful cuff stimulations).

RESULTS

Adolescents with musculoskeletal pain at age 13 plus a history of pain in previous evaluations (longitudinal definition) had lower pain tolerance thresholds compared to the remaining sample (40.2 v. 49.0 kPa, p = 0.02), but showed no differences in pain detection threshold, CPM effect and TSP effect. Pain sensitivity, CPM effects and TSP effects were not significantly different when the current pain only case definition (cross-sectional) was used.

CONCLUSIONS

Adolescents with current musculoskeletal pain who had a history of pain since childhood had lower tolerance to cuff stimulation. This may suggest long-standing musculoskeletal pain since childhood may contribute to sensitisation, rather than the presence of current pain only.

SIGNIFICANCE

Repeated musculoskeletal pain up to age 13 years may contribute to higher pain sensitivity (particularly lowered pressure pain tolerance) in the general adolescent population. This does not seem to be the case when reported pain experiences are recent or when the outcomes are temporal pain summation or CPM. In this community-based paediatric sample, the vast majority showed no sign of altered pain processing, but a small fraction may reveal some pain sensitization at 13 years of age.

The Effect of a Psychologically Informed Video Series to Treat Adolescents With Patellofemoral Pain: A Randomized Controlled Trial

OBJECTIVE: To test whether a series of brief, psychologically informed educational videos added to physical therapy improved function among adolescents with patellofemoral pain. The secondary aims were to assess pain and psychological beliefs. DESIGN: A double-blinded randomized controlled trial. METHODS: Sixty-eight adolescents with patellofemoral pain were randomly assigned to view brief, psychologically informed videos (n = 34) or control videos (n = 34) in addition to usual care physical therapy. The psychologically informed videos targeted fear-avoidance beliefs, kinesiophobia, and pain catastrophizing. The control videos conveyed basic anatomy, biomedical factors, and lower extremity mechanics. Outcomes were assessed at baseline, 3 weeks, 6 weeks (primary end point), and 3 months. The primary outcome was change in the Anterior Knee Pain Scale. Secondary outcomes were changes in Numeric Pain-Rating Scale and psychological beliefs (Modified Fear-Avoidance Beliefs Questionnaire-Physical Activity, Tampa Kinesiophobia Scale-11, and Pain Catastrophizing Scale-Child). RESULTS: Adolescents in the psychologically informed group experienced significantly greater improvements in function (Anterior Knee Pain Scale mean difference = 8 points; 95% CI: 2.2, 13.2; P = .01) and pain (Numeric Pain-Rating Scale mean difference = 1.2 points; 95% CI: 0.1, 2.4; P = .04) at 6 weeks compared to the control group. The psychologically informed group had significantly greater reductions in psychological beliefs over time than the control group (P≤.001; partial η2 = 0.32). CONCLUSION: Incorporating psychologically informed education into physical therapy care improved function, pain, and psychological beliefs to a greater extent than the control group. J Orthop Sports Phys Ther 2023;53(10):1-9. Epub: 14 September 2023. doi:10.2519/jospt.2023.12041.

Do adolescents with Osgood-Schlatter display nociplastic pain manifestations compared to controls: A cross-sectional study

OBJECTIVES

Osgood-Schlatter disease is an overuse musculoskeletal pain condition. The pain mechanism is considered nociceptive, but no studies have investigated nociplastic manifestations. This study investigated pain sensitivity and inhibition evaluated through exercise-induced hypoalgesia in adolescents with and without Osgood-Schlatter.

DESIGN

Cross-sectional study.

METHODS

Adolescents underwent a baseline assessment comprising clinical history, demographics, sports participation, and pain severity rated (0-10) during a 45-second anterior knee pain provocation test, consisting of an isometric single leg squat. Pressure pain thresholds were assessed bilaterally at the quadriceps, tibialis anterior muscle, and the patella tendon before and after a three-minute wall squat.

RESULTS

Forty-nine adolescents (27 Osgood-Schlatter, 22 controls) were included. There were no differences in the exercise-induced hypoalgesia effect between Osgood-Schlatter and controls. Overall, an exercise-induced hypoalgesia effect was detected at the tendon only in both groups with a 48 kPa (95 % confidence interval 14 to 82) increase in pressure pain thresholds from before to after exercise. Controls had higher pressure pain thresholds at the patellar tendon (mean difference 184 kPa 95 % confidence interval 55 to 313), tibialis anterior (mean difference 139 kPa 95 % confidence interval 24 to 254), and rectus femoris (mean difference 149 kPa 95 % confidence interval 33 to 265). Higher anterior knee pain provocation severity was associated with lower exercise-induced hypoalgesia at the tendon (Pearson correlation = 0.48; p = 0.011) in participants with Osgood-Schlatter.

CONCLUSIONS

Adolescents with Osgood-Schlatter display increased pain sensitivity locally, proximally, and distally but similar endogenous pain modulation compared to healthy controls. Greater Osgood-Schlatter severity appears to be associated with less efficient pain inhibition during the exercise-induced hypoalgesia paradigm.

Body image dissatisfaction and experimental pressure pain sensitivity in a cohort of 13-year-old adolescents

OBJECTIVE

We aimed to quantify the associations between body image (dis)satisfaction and pressure pain thresholds in adolescents, using data from Generation XXI, a population-based cohort study in Portugal.

METHODS

We assessed 1785 13-year old adolescents cross-sectionally. Body image satisfaction was measured using the Children's Figure Rating Scale. Pain detection and tolerance thresholds were assessed using cuff pressure algometry. We quantified the associations between body image categories (satisfied, prefers slightly thinner, prefers much thinner, and prefers heavier) and pain detection and tolerance thresholds using linear and logistic regression for continuous and binary (odds of achieving the highest distribution quarter) outcomes, respectively. Models were adjusted to pubertal stage and body mass index.

RESULTS

Adolescents who desired a heavier silhouette had lower pressure pain tolerance thresholds when compared to those who were satisfied (linear regression coefficient: -3.95; 95% confidence interval: -6.68, -1.21), which was more precise in boys (-3.51; -7.17, -0.08). Those adolescents also had lower odds of achieving the highest quarter of pressure pain tolerance threshold (odds ratio: 0.66; 0.48, 0.90), especially girls (0.58; 0.35, 0.98). Adolescents who desired much thinner silhouettes had lower odds of achieving the highest quarter of pressure pain tolerance (0.68; 0.46, 1.00), and this was clearer in girls (0.66; 0.48, 0.90). Pain detection thresholds did not show robust associations with body image dissatisfaction.

CONCLUSION

Our study suggests an association between satisfaction with one's silhouette and pain tolerance in adolescents from the general population, arguing for an integrated approach to the assessment of body image and pain sensitivity.

Does central nervous system dysfunction underlie patellofemoral pain in young females? Examining brain functional connectivity in association with patient-reported outcomes

Patellofemoral pain (PFP) is defined as retro- or peri-patellar knee pain without a clear structural abnormality. Unfortunately, many current treatment approaches fail to provide long-term pain relief, potentially due to an incomplete understanding of pain-disrupted sensorimotor dysfunction within the central nervous system. The purposes of this study were to evaluate brain functional connectivity in participants with and without PFP, and to determine the relationship between altered brain functional connectivity in association with patient-reported outcomes. Young female patients with PFP (n = 15; 14.3 ± 3.2 years) completed resting-state functional magnetic resonance imaging (rs-fMRI) and patient-reported outcome measures. Each patient with PFP was matched with two controls (n = 30, 15.5 ± 1.4 years) who also completed identical rs-fMRI testing. Six bilateral seeds important for pain and sensorimotor control were created, and seed-to-voxel analyses were conducted to compare functional connectivity between the two groups, as well as to determine the relationship between connectivity alterations and patient-reported outcomes. Relative to controls, patients with PFP exhibited altered functional connectivity between regions important for pain, psychological functioning, and sensorimotor control, and the connectivity alterations were related to perceived disability, dysfunction, and kinesiophobia. The present results support emergent evidence that PFP is not localized to structural knee dysfunction, but may actually be resultant to altered central neural processes. Clinical significance: These data provide potential neuro-therapeutic targets for novel therapies aimed to reorganize neural processes, improve neuromuscular function, and restore an active pain-free lifestyle in young females with PFP.

Brain Activity During Experimental Knee Pain and Its Relationship With Kinesiophobia in Patients With Patellofemoral Pain: A Preliminary Functional Magnetic Resonance Imaging Investigation

Context: The etiology of patellofemoral pain has remained elusive, potentially due to an incomplete understanding of how pain, motor control, and kinesiophobia disrupt central nervous system functioning. Objective: To directly evaluate brain activity during experimental knee pain and its relationship to kinesiophobia in patients with patellofemoral pain. Design: Cross-sectional. Methods: Young females clinically diagnosed with patellofemoral pain (n = 14; 14.4 [3.3] y; body mass index = 22.4 [3.8]; height = 1.61 [0.1] m; body mass = 58.4 [12.7] kg). A modified Clarke test (experimental pain condition with noxious induction via patella pressure and quadriceps contraction) was administered to the nondominant knee (to minimize limb dominance confounds) of patients during brain functional magnetic resonance imaging (fMRI) acquisition. Patients also completed a quadriceps contraction without application of external pressure (control contraction). Kinesiophobia was measured using the Tampa Scale of Kinesiophobia. The fMRI analyses assessed brain activation during the modified Clarke test and control contraction and assessed relationships between task-induced brain activity and kinesiophobia. Standard processing for neuroimaging and appropriate cluster-wise statistical thresholds to determine significance were applied to the fMRI data (z > 3.1, P < .05). Results: The fMRI revealed widespread neural activation in the frontal, parietal, and occipital lobes, and cerebellum during the modified Clarke test (all zs > 4.4, all Ps < .04), whereas neural activation was localized primarily to frontal and cerebellar regions during the control contraction test (all zs > 4.4, all Ps < .01). Greater kinesiophobia was positively associated with greater activity in the cerebello-frontal network for the modified Clarke test (all zs > 5.0, all Ps < .01), but no relationships between kinesiophobia and brain activity were observed for the control contraction test (all zs < 3.1, all Ps > .05). Conclusions: Our novel experimental knee pain condition was associated with alterations in central nociceptive processing. These findings may provide novel complementary pathways for targeted restoration of patient function.

Exploring the Pain in Patellofemoral Pain: A Systematic Review and Meta-Analysis Examining Signs of Central Sensitization

BACKGROUND

Patellofemoral pain (PFP) has high recurrence rates and minimal long-term treatment success. Central sensitization refers to dysfunctional pain modulation that occurs when nociceptive neurons become hyperresponsive. Researchers in this area of PFP have been increasingly productive in the past decade.

OBJECTIVE

To determine whether evidence supports manifestations of central sensitization in individuals with PFP.

DATA SOURCES

We searched MeSH terms for quantitative sensory testing (QST) pressure pain thresholds (PPTs), conditioned pain modulation (CPM), temporal summation, sensitization, hyperalgesia, and anterior knee pain or PFP in PubMed, SPORTDiscus, CINAHL, Academic Search Complete, and EBSCOhost.

STUDY SELECTION

Peer-reviewed studies that were written in English and published between 2005 and 2020 and investigated QST or pain mapping in a sample with PFP were included in this review.

DATA EXTRACTION

The initial search yielded 140 articles. After duplicates were removed, 78 abstracts were reviewed. The full text of 21 studies was examined, and we included 15 studies in our evaluation: 6 in the meta-analysis, 4 in the systematic review, and 5 in both the meta-analysis and systematic review.

DATA SYNTHESIS

A random-effects meta-analysis was conducted for 4 QST variables (local PPTs, remote PPTs, CPM, temporal summation). Strong evidence supported lower local and remote PPTs, impaired CPM, and facilitated temporal summation in individuals with PFP compared with pain-free individuals. Evidence for heat and cold pain thresholds was conflicting. Pain mapping demonstrated expanding pain patterns associated with long duration of PFP symptoms.

CONCLUSIONS

Signs of central sensitization were present in individuals with PFP, indicating altered pain modulation. The etiologic and treatment models of PFP should reflect the current body of evidence regarding central sensitization. Signs of central sensitization should be monitored clinically, and treatments with central effects should be considered as part of a multimodal plan of care.

Prognosis and transition of multi-site pain during the course of 5 years: Results of knee pain and function from a prospective cohort study among 756 adolescents

INTRODUCTION

Multi-site pain has not been investigated among adolescents suffering from knee pain. This study aimed to examine the trajectory of pain in adolescents with knee-pain, to determine if multi-site pain in adolescents together with other established prognostic factors (frequency of pain, sex, sports participation, Health Related Quality of Life (HRQoL)) was associated with five-year prognosis of knee-pain and function.

METHODS

This prospective cohort study included 504 adolescents with knee pain and 252 controls. At five-year follow-up, participants responded to an questionnaire which documented prescence and severity of knee pain and co-occurring pain.

RESULTS

At follow-up, 358 (71.0%) of those with knee-pain at baseline, and 182 (72.2%) controls responded. Female sex, low HRQoL, daily pain, and multi-site pain were associated with an increased odds of knee pain after 5 years (odds ratio: 1.41-3.37). Baseline multi-site pain was not associated with problems running at follow-up, whereas higher sports participation at baseline was associated with less problems running at follow-up (odd ratio 0.49). Among those with knee-pain at inclusion, the number of pain sites increased from a median of 2 (IQR 1-3) to 4 (IQR 2-6) at follow-up (P<0.05). Those with multi-site pain at follow-up score significantly worse in self-reported knee function, compared to those with one pain site only.

CONCLUSION

This study identified a set of factors that appeared to be associated with an increased risk of knee pain at five years follow up. Research is needed to understand and help direct treatment of adolescents with multi-site pain.

Phenotyping peripheral neuropathic pain in male and female adolescents: pain descriptors, somatosensory profiles, conditioned pain modulation, and child-parent reported disability

ABSTRACT

Neuropathic pain (NeuP) can be difficult to diagnose and manage in children. Data regarding prevalence and sex-dependent differences are limited, and more detailed phenotyping is needed. This observational cohort study recruited adolescents (10-17 years) with NeuP or complex regional pain syndrome (CRPS). After pain history and NeuP questionnaires, quantitative sensory testing was performed. Individual z-score plots were calculated with body-region control measures and matched to mechanism-related sensory profiles (sensory loss, thermal hyperalgesia, and mechanical hyperalgesia). Conditioned pain modulation was assessed with pressure pain threshold and a contralateral cold conditioning stimulus, and meaningful conditioned pain modulation defined as twice the standard error of measurement. Patients and parents completed validated questionnaires for child quality of life (QoL), pain catastrophizing, and self-reported anxiety/depression. Males (n = 23) and females (n = 43) with NeuP (n = 52) or CRPS (n = 14) reported moderate-severe pain with neuropathic sensory descriptors. Mixed patterns of sensory gain/loss at pain sites were not sex-dependent. Thermal hyperalgesia was common in both NeuP and CRPS, whereas sensory loss occurred only with NeuP and in a smaller proportion than adult cohorts. Conditioned pain modulation was inhibitory in 54%, facilitatory in 14%, and nonresponders had variable cold conditioning sensitivity. Males and females reported marked impairment of QoL, increased emotional distress, and pain catastrophising. Child-parent QoL scores correlated, but catastrophizing scores were discordant when parents or adolescents reported higher anxiety/depression. NeuP in adolescents is associated with significant pain, physical impairment, and psychosocial impairment. Quantifying alterations in somatosensory profiles, descending modulation, child and parent psychological function will inform individualized therapy and stratification for future clinical trials.

Prognostic factors for adolescent knee pain: an individual participant data meta-analysis of 1281 patients

ABSTRACT

Adolescent knee pain has a propensity for chronicity, impacting physical activity and health into adulthood. The aim of this study is to investigate prognostic factors in adolescents with knee pain using individual participant data (IPD) meta-analysis. Studies were identified through a systematic search and a collaborative group. We included IPD from prospective studies of adolescents (age 10-19 years) with nontraumatic knee pain (13 studies and 1516 adolescents with 1281 unique participants). Primary outcomes were pain intensity and function (Knee Injury and Osteoarthritis Outcome Score "Sport/Rec" subscale). Primary endpoint was 12 months. Risk of bias was appraised with Quality in Prognosis Studies tool. Harmonised IPD was analysed by multilevel modelling. Fifty-one percent reported knee pain after 12-months. Lower baseline pain frequency was associated with lower pain intensity at 12 months ("less than weekly"; 12 (95% confidence interval [CI] 7-17) and "monthly"; 15 (95% CI 9-22) points lower on a 100-point pain scale, compared with "almost daily pain"). Other factors most strongly associated with 1-year pain prognosis were lower quality of life (30, 95% CI 19-42 points per unit change in the EQ5D index score), female sex (8 points, 95% CI 4-12 higher compared with males), and bilateral pain (7, 95% CI 1-13 points higher pain). Similar factors were associated with function. Body mass index, pain sensitivity, and knee strength were not associated with prognosis of pain or function. Adolescent knee pain is associated with clinically relevant long-term pain and functional deficits. Self-reported characteristics may help identify those at risk of poor prognosis.