Use of IMMPACT Recommendations to Explore Pain Phenotypes in People with Knee Osteoarthritis

Hand osteoarthritis phenotypes based on a biopsychosocial approach, and their associations with cross-sectional and longitudinal pain

OBJECTIVE

Hand osteoarthritis (OA) pain is characterized as heterogeneous and multifactorial. Differences in pain may be explained by underlying phenotypes, which have not been previously explored DESIGN: Latent class analysis determined classes of participants with hand OA from the Nor-Hand study baseline examination (2016-17) based on a biopsychosocial framework. Outcomes were hand and overall bodily pain intensity (Numeric Rating Scale, 0-10) at baseline and follow-up (2019-21), The relations of the classes to pain outcomes at baseline, follow-up, and change over time were analysed in separate models by linear regression, using the overall healthiest class as reference.

RESULTS

Five classes differing in radiographic hand OA burden and OA burden in the lower extremities by ultrasound, demographic factors, psychosocial burden and pain sensitization was identified. Persons with the least severe OA but higher burden of biopsychosocial factors reported the most hand pain (beta 3.65, 95% CI 2.53, 4.75). Pain was less pronounced in persons with the most severe hand OA but low burden of biopsychosocial factors (beta 1.03, 95% CI 0.41, 1.65). Results were similar for overall bodily pain and at follow-up. Changes in pain were small, but the association between a separate class defined by higher levels of biopsychosocial burden and pain changes was significant.

CONCLUSION

The five hand OA phenotypes were associated with pain at baseline and 3.5 years later. The phenotype with the least OA severity, but higher burden of biopsychosocial factors reported more pain than the phenotype with the most severe OA, reflecting the symptom-structure discordance of the hand OA pain experience.

Exploring the association of gender role expectations of pain and measures of pain sensitization in people with knee osteoarthritis: A cross-sectional study

OBJECTIVES

First, we explored the association between Gender Role Expectations of Pain (GREP), and psychophysical measures of sensitization in people with knee osteoarthritis (OA). Second, we explored whether the association differed by level of GREP items (high vs low scores).

DESIGN

We conducted secondary analyses of a cohort study. Those who were (i) age of ≥40, English or French speaking, ii) diagnosed with knee OA using American College of Rheumatology criteria and iii) consulting with an orthopedic surgeon were included. GREP items pertaining to pain sensitivity and pain endurance of the typical man or woman were rated by males and females respectively. Psychophysical tests consisted of pressure pain thresholds (PPTs), Temporal Summation (TS), and Conditioned Pain Modulation (CPM). Multiple linear regression models for males and females were run with GREP scores (independent variables) and psychophysical tests (dependent variables). Next models stratified on the median split of GREP scores were run. Models were adjusted for age, BMI, pain catastrophizing, anxio-depressive symptoms, and radiographic severity.

RESULTS

280 participants (57% females; age (SD): 63.9 (9.6) and BMI (SD): 31.3 (8.40)) were included. GREP pain sensitivity scores in males were associated with CPM values (β: 95% CI: 0.09 (0.01 to 0.17)). Males with low GREP pain sensitivity or pain endurance had very small to small positive associations with PPT and CPM values.

CONCLUSION

This first exploration of gendered pain sensitivity and pain endurance by males and females has small and clinically unimportant associations with measures of pain sensitization requiring further validation.

Activity-related pain and sensitization predict within- and between-person pain experience in people with knee osteoarthritis: An ecological momentary assessment study

Background and objectives

Knee Osteoarthritis (OA) is a prevalent musculoskeletal condition that often results in pain and disability. Determining factors predicting variability in pain experience is critical to improving clinical outcomes. Underlying pain sensitization and its clinical manifestations, such as activity-related pain, may better predict the knee OA pain experience. This study aimed to determine whether Quantitative Sensory Testing (QST) derived sensitization measures and activity-related pain predict knee OA pain experiences collected via smartphone ecological momentary assessment (EMA).

Design

Individuals with knee OA were recruited from an urban community in New Zealand. Those eligible to participate underwent baseline QST with clinical measures of activity-related pain also being collected. The knee OA pain experience was collected via smartphone EMA three times daily for two weeks. Mixed effects location scale models were developed using a multilevel modelling approach.

Results

Eighty-six participants with knee OA participated in the study. Mean age was 67.3 years, with most of the participants being female (64%) and New Zealand European (90.6%). Activity-related pain predicted worse and more variable pain intensity, pain interference, and bothersomeness outcomes within and between individuals with knee OA. Widespread cold hyperalgesia and local mechanical hyperalgesia were shown to predict higher within-person variability in pain intensity and pain interference respectively, while mechanical temporal summation predicted less within-person variability in pain intensity and interference.

Discussion

Those demonstrating activity-related pain and sensitization could be at risk of experiencing worse and more variable knee OA pain in the subsequent weeks. Testing for sensitization in clinical practice could therefore identify those at greatest risk of higher and more variable knee OA pain experiences and in greatest need of treatment. Larger validation studies are required, which include individuals with more severe knee OA.

Pain-phenotyping in osteoarthritis: Current concepts, evidence, and considerations towards a comprehensive framework for assessment and treatment

Objectives

Pain as central symptom of osteoarthritis (OA) needs to be addressed as part of successful treatment. The assessment of pain as feature of disease or outcome in clinical practice and drug development remains a challenge due to its multidimensionality and the plethora of confounders. This article aims at providing insights into our understanding of OA pain-phenotypes and suggests a framework for systematic and comprehensive assessments.

Methods

This narrative review is based on a search of current literature for various combinations of the search terms "pain-phenotype" and "knee OA" and summarizes current knowledge on OA pain-phenotypes, putting OA pain and its assessment into perspective of current research efforts.

Results

Pain is a complex phenomenon, not necessarily associated with tissue damage. Various pain-phenotypes have been described in knee OA. Among those, a phenotype with high pain levels not necessarily matching structural changes and a phenotype with low pain levels and impact are relatively consistent. Further subgroups can be differentiated based on patient reported outcome measures, assessments of comorbidities, anxiety and depression, sleep, activity and objective measures such as quantitative sensory testing.

Conclusions

The complexity of both OA as disease and pain in OA prompt the definition of a set of variables that facilitate assessments comparable across studies to maximize our understanding of pain, as central concern for the patient.

Potential Mechanisms Underlying the Therapeutic Roles of Gancao fuzi Decoction in Cold-dampness Obstruction Syndrome-type Knee Osteoarthritis

BACKGROUND

The key active components and potential molecular mechanism of Gancao Fuzi decoction (GFD) in the treatment of cold-dampness obstruction-type knee osteoarthritis (KOA) remain unclear.

OBJECTIVES

To explore the mechanism of GFD in the treatment of cold-dampness obstruction syndrome-type KOA by network pharmacology.

METHODS

The potential active components and targets of the four herbs in GFD (Fuzi, Guizhi, Baizhu, and Gancao) were screened using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. The targets of KOA were obtained with the Comparative Toxicogenomics Database (CTD), the GeneCards database, and the DisGeNET database, and the common targets of the drugs and disease were ultimately obtained. Cytoscape (v.3.7.1) was used to draw the active component-target network, and the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) (v.11.0) database was used to construct the protein interaction network. The Database for Annotation, Visualization, and Integrated Discovery (DAVID) was used for the Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the intersecting targets.

RESULTS

A total of 102 potential active components and 208 targets of GFD in the treatment of cold-dampness obstruction syndrome-type KOA were screened. GFD treatment was found to be closely related to many inflammatory signalling pathways in the treatment of KOA.

CONCLUSION

The effect of GFD on cold-dampness obstruction syndrome-type KOA is mediated by multicomponent, multitarget, and multichannel mechanisms, which provides the basis for further experimental study of its pharmacodynamic material basis and mechanism.

The Natural History of Knee Osteoarthritis Pain Experience and Risk Profiles

The study aimed to characterize the natural history of the pain experience, concurrently considering intermittent and constant pain over 4 years, and determine baseline factors associated with unfavorable trajectories in individuals with chronic knee pain. The Osteoarthritis Initiative (OAI) is a prospective, observational study of people with or at higher risk for knee osteoarthritis. The Intermittent and Constant Osteoarthritis Pain (ICOAP) was assessed annually at 48-to-96-month OAI visits. Twenty-eight baseline sociodemographic, knee-specific, and health-related characteristics were assessed. Group-based dual-trajectory modeling identified pain experience patterns indicated by ICOAP intermittent and constant pain scores over 4 years. Multivariable multinomial logistic regression models determined baseline factors associated with membership in each dual-trajectory group. Four longitudinal pain experience patterns were identified (n = 3,584, mean age = 64.8 [standard deviation 9.0] years, BMI = 28.6 [5.0] kg/m2; 57.9% women). Group 1 (37.7%) had minimal intermittent and no constant pain; Group 2 (35.1%) had mild intermittent and no constant pain; Group 3 (18.5%) had mild intermittent and low-grade constant pain; and Group 4 (8.7%) had moderate intermittent and constant pain. Baseline widespread pain, knee stiffness, back pain, hip pain, ankle pain, obesity, depressive symptoms, more advanced radiographic disease, and analgesic use were each associated with an increased risk of membership in less favorable Groups 2, 3, and 4. These distinct courses of pain experience may be driven by different underlying pain mechanisms. The benchmarked ICOAP scores could be used to stratify patients and tailor management. Addressing and preventing the development of modifiable risks (eg, widespread pain and knee joint stiffness) may reduce the chance of belonging to unfavorable dual-trajectory groups. PERSPECTIVE: Concurrently tracking intermittent versus constant pain experience, group-based dual-trajectory modeling identified 4 distinct pain experience patterns over 4 years. The benchmarked ICOAP scores in these dual trajectories could aid in stratifying patients for tailored management strategies and intensity of care.

Myofascial Pain as an Unseen Comorbidity in Osteoarthritis: A Scoping Review

OBJECTIVE

This review aimed to identify, summarize, and appraise the evidence supporting the coexistence of myofascial pain (MPS) and trigger points (MTrP) in osteoarthritis (OA), and the effectiveness of MTrPs treatments in OA-related pain and physical function outcomes.

METHODS

Three databases were searched from inception to June 2022. We included observational and experimental studies to fulfill our 2 study aims. Two independent reviewers conducted 2-phase screening procedures and risk of bias using checklist tools for cross-sectional, quasi-experimental, and randomized control trials. Patient characteristics, findings of active and latent MTrPs in relevant muscles, treatments, and pain and physical function outcomes were extracted from low-risk bias studies.

RESULTS

The literature search yielded 2898 articles, of which 6 observational and 7 experimental studies had a low bias risk and the data extracted. Active MTrPs in knee OA patients was more evident in the quadriceps and hamstring muscles than in healthy individuals. Dry needling on active MTrPs improved pain and physical function in the short term compared with sham treatment in hip OA patients. In knee OA, dry needling on latent or active MTrPs improved pain and functional outcomes compared with sham needling but did not result in better pain and physical outcomes when combined with a physical exercise program.

DISCUSSION

The presence of active versus latent MTrPs seems to be a more sensitive discriminating feature of OA given that latent is often present in OA and healthy individuals. Dry needling on active MTrPs improved pain and physical function in the short term compared with sham treatment in hip OA patients. However, the small sample size and the few number of studies limit any firm recommendation on the treatment.

REGISTRY

The study protocol was prospectively registered in Open Science Framework (https://doi.org/10.17605/OSF.IO/8DVU3).

Biological Targets of Multimolecular Therapies in Middle-Age Osteoarthritis

Knee osteoarthritis (OA) is a common condition, prevalent in middle-agedness, associated with chronic pain and impaired quality of life. Two interrelated biological processes fuel early OA progression: inflammation and structural tissues catabolism. Procatabolic and proinflammatory mediators are interconnected and form part of a self-perpetuating loop. They leverage OA research complexity because of the impossibility to discern certain spatiotemporal tissues' changes from others. Both are shared targets of versatile regenerative multimolecular therapies. In particular, platelet-rich plasma can interfere with inflammation and inflammatory pain. The therapeutic approach is to alter the vicious inflammatory loop by modifying the molecular composition of the synovial fluid, thereby paracrine cellular cross talk. Intra-articular injections of platelet-rich plasma can provide key factors balancing proinflammatory and anti-inflammatory factors, targeting macrophage dysfunction and modulating immune mechanisms within the knee.