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

Subgrouping of facilitatory or inhibitory conditioned pain modulation responses in patients with chronic knee pain. Explorative analysis from a multicentre trial

BACKGROUND

Facilitatory and inhibitory conditioned pain modulation (CPM) responses are observed in healthy volunteers and chronic pain patients, but the clinical implications for phenotyping are unknown. This study aimed to subgroup and compare chronic knee pain patients according to their CPM responses.

METHODS

This explorative, cross-sectional study included 127 patients with chronic knee pain (osteoarthritis or following total knee arthroplasty). Individual CPM responses were categorized as facilitatory (test stimuli pain intensity increased when conditioning stimuli were applied), as inhibitory (test stimuli pain intensity decreased) or as no change (defined as less than 5.3% change in pain intensity). Outcomes were clinical pain intensities, temporal summation, widespread pain, self-reported physical function, PainDETECT questionnaire and Pain Quality Assessment Scale. Data were analysed as comparisons between the inhibitory and the facilitatory groups and using multivariate linear regression models.

RESULTS

Fifty-four patients had facilitatory CPM responses, 49 had inhibitory CPM responses, and 24 showed no change in CPM response. A between-group difference was observed for self-reported physical function, with the facilitatory CPM group reporting better function (54.4 vs. 46.0, p = 0.028) and the facilitatory CPM group reported more deep pain sensations (3.2 vs. 2.0, p = 0.021). The remaining outcomes showed no between-group differences. Higher clinical pain intensity and facilitated temporal summation were associated in the facilitated CPM group but not in the inhibitory CPM group.

CONCLUSION

These explorative findings indicated that quantitative clinical and experimental differences exist between facilitatory or inhibitory CPM responses in a chronic knee pain patient population. Differences in patients' CPM responses should be further investigated to unravel possible clinical importance.

SIGNIFICANCE

Our findings confirm that conditioned pain modulation consist of inhibitory and facilitatory responders among a patient population with chronic knee pain. This explorative study indicates that patients with either facilitatory or inhibitory conditioned pain modulation could exhibit differences in pain outcomes. Subgrouping of chronic pain patients depending on individual conditioned pain modulation responses could be considered in phenotyping patients prior to inclusion in clinical trials or used for personalizing the management regime.

Flat flexible school shoes for adolescents with patellofemoral pain: a randomised, assessor-blinded, parallel-group feasibility trial

Objectives

To determine the feasibility of conducting a large-scale randomised controlled trial on the efficacy of flat, flexible school footwear versus traditional school footwear in adolescents (aged 12-18 years) with patellofemoral pain (PFP).

Methods

Adolescents with PFP were recruited for this study. Participants were randomised to wear either a (1) flat, flexible school shoe or (2) a traditional school shoe. Participants wore the shoes as per school requirements for 12 weeks. Feasibility was assessed by (1) adherence to allocated shoe wear of ≥75% of total weekly school shoe wear time (recorded through weekly log sheets), (2) a recruitment rate of one participant per fortnight and (3) a dropout rate of ≤ 20%. Descriptive statistics were used for feasibility outcomes.

Results

24 adolescents (15 men, 9 women, mean (SD) age 14.3 (1.7) years) participated in this study. Two participants (8%) were lost to follow-up. The recruitment rate was 1.7 participants per fortnight. 11 of 12 participants (91%) in the flat flexible shoe group and 9 of 10 participants (90%) in the traditional shoe group met the minimum adherence for shoe wear. Mean weekly shoe wear was 20 (7.6) and 21 (4.5) hours per week in the flat, flexible, and traditional shoe groups, respectively.

Conclusion

Our results indicate that progression to a full-scale randomised controlled trial is feasible based on the current protocol. A full-scale randomised controlled trial powered to detect estimates of treatment efficacy using flat, flexible school shoes versus traditional school shoes is warranted and will guide evidence-based management of adolescent PFP.

Exploring the pain and disability continuum in adolescents with non-traumatic anterior knee pain: a mediation analysis using individual participant data of prospective studies

OBJECTIVE

To use individual patient data (IPD) to investigate if the effect of pain on sports-related disability is mediated through physical (lower extremity isometric strength) or psychological (depression/anxiety and knee confidence) factors in adolescents with non-traumatic anterior knee pain.

METHODS

This study included four datasets from a previously harmonised IPD dataset. Prior to analysis, the protocol and analysis approach were predefined and published on Open Science Framework. Potential mediators were pre-sepcified as isometric knee and hip strengths, self-reported anxiety/depression and confidence in the knee, allmeasured at 12 weeks after baseline evaluation. Mediation analyses were undertaken using the CMAVerse package in RStudio using the regression-based approach to decompose the total effect of the exposure (pain at baseline evaluation) on the outcome (sports-related disability at 6 months) into the 'indirect effect' (the portion of the total effect acting through the mediators) and the 'direct effect'.

RESULTS

Two-hundred and seventy-nine adolescents with non-traumatic knee pain were included in the analysis. Median age was 13 (range 10-19), and 72% were women. Baseline pain was associated with sports-related disability at 6 months. There was no evidence of the association being mediated by any of the proposed mediators (total natural indirect effect for strength 0.01 (-1.14 to 1.80) and psychological factors 0.00 (-0.66 to 2.02)).

CONCLUSION

We found an effect of pain on sports-related disability at 6 months which appears to be independent of lower extremity muscle strength, or depression/anxiety and knee confidence in adolescents with non-traumatic anterior knee pain.

Bio-psycho-social characteristics and impact of musculoskeletal pain in one hundred children and adolescents consulting general practice

Background

Eight percent of all child and adolescent general practice consultations are due to musculoskeletal conditions, with pain as the most frequent symptom. Despite the commonality of musculoskeletal pain, limited knowledge exists about care-seeking children and adolescents with musculoskeletal pain.

The purpose of this study was to describe characteristics of children and adolescents consulting their general practitioner with musculoskeletal pain.

Methods

This is a cross-sectional study based on baseline data from the child and adolescent musculoskeletal pain cohort study (ChiBPS), carried out in 17 Danish general practice clinics. Patients aged 8–19 years who had musculoskeletal pain when consulting their general practitioner were recruited. Participants completed a questionnaire on demographics, physical activity, pain impact, psychosocial factors, and expectations of their general practitioner. Descriptive statistics were used to summarize data. Normally distributed continuous data were described using mean and standard deviation while non-normally data were described using median and interquartile range (IQR).

Results

We included 100 participants (54% female, median age 13 [IQR: 12–16.5 years]). Frequent pain sites limiting activity were knee (56%), back (20%), ankle (19%), and neck (13%). Most participants (63%) consulted their general practitioner due to inability to use their body as usual, due to pain. Median pain duration at consultation was 5 months [IQR: 3 weeks-1 year]. More than a third were often/sometimes nervous (34%), worried or anxious (33%), and took pain medication (33%). Pain impeded ability to participate in sport activities at school (79%) and disturbed spare time activities (88%). Pain also made it difficult to concentrate for 58%, and to fall asleep for 38%. Only 38% expected a pain free long-term future.

Conclusion

This study demonstrates the bio-psycho-social impact of musculoskeletal pain in care-seeking children and adolescents. Demographics, pain characteristics, psychosocial characteristics, and physical characteristics should be included in addressing children and adolescents with musculoskeletal pain.

Trial registration

The ChiBPS study was pre-registered before participant recruitment (ClinicalTrials.gov Identifier: NCT03678922) date: 09.20.18.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01628-8.