Triggers for acute flare in adults with, or at risk of, knee osteoarthritis: a web-based case-crossover study in community-dwelling adults

Come rain or shine: Is weather a risk factor for musculoskeletal pain? A systematic review with meta-analysis of case-crossover studies

OBJECTIVES

The weather is frequently blamed for changes in musculoskeletal health behaviour and adverse events. However, despite the frequency with which this phenomenon is endorsed, past research is largely conflicting. This meta-analysis has reviewed, appraised and summarised case-crossover studies assessing the transient risk of musculoskeletal health events associated with weather parameters (e.g. temperature, relative humidity, air pressure, and precipitation).

METHODS

A meta-analysis of case-crossover studies was conducted. Two reviewers independently searched MEDLINE, EMBASE, CINAHL, Web of Science, Scopus, and PsycINFO from inception to 10/09/2023. Published studies that employed a case-crossover design to evaluate the risk of musculoskeletal health events (e.g. symptoms, hospitalisation) associated with weather parameters were included. Primary outcome was pain (new episodes of pain or flares). Quality of included studies was assessed based on selection bias, exposure assessment, confounding, and outcome assessment. Pooling of results was conducted using random effects models and separately performed for each condition and weather factor. Heterogeneity among included studies was assessed using I2 measures.

FINDINGS

Of the 1,107 studies identified in the search, 11 were included (15,315 participants), providing data on 28,010 events (102,536 control periods), for seven musculoskeletal conditions. Pooled analyses showed no association between relative humidity, air pressure, temperature, or precipitation and the risk of rheumatoid arthritis, knee pain or low back pain. High temperatures combined with low humidity were associated with increased pain, redness, and joint swelling in people with gout (Odds Ratio: 2.04; 95 % Confidence Interval: 1.26 to 3.30).

INTERPRETATION

Despite anecdotal reports from patients, changes in weather factors do not seem to be risk factors for rheumatoid arthritis, knee, hip, or low back pain, but may have a significant influence in gout disease.

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.

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.

A scoping review of patient self-report measures of flare in knee and hip osteoarthritis (OA): A report from the OMERACT flares in OA working group

PURPOSE

We aimed to analyze the content validity/domain match and feasibility of self-report instruments that could measure flare in osteoarthritis (OA), by extending our 2017 literature review on the definition of flare in knee and hip OA.

METHOD

We searched PubMed (Medline), Web of Science and PsycInfo (Ebsco Host) databases for original articles reporting research about flare (or synonyms) in humans with knee and hip OA, between 2017 and 2023. Four experts worked independently, checking the records, and assessing content validity and feasibility, writing justification for exclusion.

RESULTS

At literature review phase, 575 papers were filtered. After experts' analysis, 59 studies were included, and 44 instruments associated with flare in OA were identified. Most were studies about pain in knee or hip OA (35 %), cultural adaptation of a measure (33 %) or studies investigating psychometric properties of full (16 %) or short form (4 %) instruments. The assessment of domain match and feasibility revealed that 15 instruments were assigned a label of 'yes' or 'uncertain' as to whether or not there was a good match with the domain concept or whether the instrument was considered feasible to use.

DISCUSSION

Most identified instruments considered different aspects of pain and the associated discomfort in performing daily activities but did not include the central aspects of flare in OA, i.e. the change of state, nor the additional Outcome Measures in Rheumatology (OMERACT) endorsed domains for OA flare namely stiffness, swelling, psychological aspects, impact of symptoms including fatigue and sleep disturbance. Although it is possible that the period specified to conduct this literature review may have led to some recognized instruments being excluded, this review demonstrates the need for the research community to reach consensus on the best way to measure self-reported flares in future clinical trials and observational studies.

Assessment of Pain in Osteoarthritis of the Knee

Knee osteoarthritis (KOA) pain is a subjective and personal experience, making it challenging to characterise patients' experiences and assess their pain. In addition, there is no global standard for the assessment of pain in KOA. Therefore, this article examines the possible methods of assessing and characterising pain in patients with KOA using clinical symptoms, pain assessment tools, and imaging. We examine the current methods of assessment of pain in KOA and their application in clinical practice and clinical trials. Furthermore, we explore the possibility of creating individualised pain management plans to focus on different pain characteristics. With better evaluation and standardisation of pain assessment in these patients, it is hoped that patients would benefit from improved quality of life. At the same time, improvement in pain assessment would enable better data collection regarding symptom response in clinical trials for the treatment of osteoarthritis.

Quantifying sustained pain worsening in knee osteoarthritis

OBJECTIVE

Recent work suggests that many persons with knee osteoarthritis (OA) experience stable symptoms over time. Whether patients experience periods of symptom exacerbation or flare which interrupt this stable course, and how long such periods last, has received little study. Our objective is to describe the frequency and duration of episodes of pain worsening in persons with knee OA.

METHODS

We selected participants from the Osteoarthritis Initiative with radiographic, symptomatic knee OA. We defined a clinically relevant increase in knee pain as an increase in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain of ≥9 points. We defined sustained worsening as maintaining at least 80% of the initial increase. We used Poisson regression to estimate the incidence rate (IR) of episodes of pain worsening.

RESULTS

1093 participants were included in the analysis. Eighty-eight percent had ≥1 increase in WOMAC pain ≥9 points (IR: 26.3 per 100 person years (95% CI: 25.2, 27.4)). Forty-eight percent had ≥1 episode of sustained worsening (IR: 9.7 per 100 person-years (95% CI: 8.9, 10.5)). Elevated pain was maintained an average of 2.4 years after the initial increase.

CONCLUSION

Most participants with knee OA reported at least one clinically relevant increase in WOMAC pain, but fewer than half experienced an episode of sustained pain worsening. These individual-level data portray a more nuanced and fluctuating course of OA pain than suggested by trajectory studies. These data could be useful in shared decision-making regarding prognosis and treatment choices in persons affected by symptomatic knee OA.

An Evaluation of Different Strategies for Sampling Controls in an Online Case-Crossover Study of Acute Flares in Knee Osteoarthritis

Objective

To evaluate bias and precision of exposure-outcome effect estimates from three control sampling strategies in a case-crossover study.

Methods

Online case-crossover study investigating eight physical activity-related triggers for acute flares in knee osteoarthritis. Exposures were measured in hazard periods (≤24 hours before self-declared flare onset). Control period exposure was measured in three ways: (1) four scheduled questionnaires over 13-weeks, (2) "usual" physical activity levels ascertained at baseline, (3) over three days before flare onset. Derived odds ratios, 95% confidence intervals and standard errors were compared.

Results

Of 744 participants (mean age 62.1 [SD 10.2] years; 61% female), 493 reported 714 flares. Selecting controls from scheduled questionnaires, independent of hazard periods, yielded predominantly odds ratios in the expected direction (exposure "a lot" versus exposure "not at all", range: 0.57-3.22). When controls were sampled at baseline (range: 0.01-1.42) or immediately before a flare (range: 0.30-1.27) most odds ratio estimates were inverted. Standard errors of the log odds ratios were smallest when controls were sampled from scheduled questionnaires (range: 0.264-0.473) compared to controls sampled at baseline (range: 0.267-0.589) or immediately before a flare (range: 0.319-0.621).

Conclusion

Our findings are sensitive to control sample selection. Under certain conditions, different patterns could be attributed to over reporting and social desirability bias, where people may want to present themselves more positively about their "usual" physical activity levels, at baseline. Exposure measurement at the time of a flare may be less precise and more susceptible to recall bias due to systematically reporting exposures differently during a flare, compared to control measurement independent of flares.

Case report: Electroacupuncture for acute pain flare-up of knee osteoarthritis

Acute pain flare-up of knee osteoarthritis (KOA) is a common disease in orthopedics and is mainly treated with analgesic drugs. Patients usually refuse to take western medicines orally owing to gastrointestinal side effects or unsatisfactory treatment results. We report the case of a 69-year-old woman who had an acute pain flare-up of right KOA induced by long-distance walking. As the patient refused medication, we used electroacupuncture (EA) to relieve her symptoms. EA with a 2-Hz frequency and a 1–2-mA intensity had an analgesic effect on the acute pain flare-up of KOA. After 12 weeks of EA intervention, the bone marrow edema-like lesions (BMLs) improved significantly, as depicted on magnetic resonance imaging of the knee joint. However, more powerful evidence is needed to understand the mechanism of the EA technique that alleviates BMLs of KOA.

Symmetry Function: The Differences between Active and Non-Active Above-the-Knee Amputees

The number of patients with unilateral above-knee amputation (AKA) due to non-vascular causes has remained stable over the years, at 0.92 per 1000 people per year. Post-AKA individuals are at risk of experiencing a higher incidence of chronic pain. Post rehabilitation, it is estimated that between 16−62% of patients with musculoskeletal disabilities fail to meet the minimum criteria for physical activity in comparison to a healthy population. The current study included 14 participants (11 men and 3 women) with a mean age of 46.1 ± 14.2 years, body height of 1.76 ± 0.09 m, and weight of 79.6 ± 18.3 kg, who were all post-unilateral above-the-knee amputees. Patients in the study were divided into two groups: active (AC) and non-active (NAC). This study was conducted in a certified Laboratory of Biomechanical Analysis using the BTS Smart-E system (BTS Bioengineering). In order to investigate the symmetry function (SF) of gait, the only measurements included were the time series assessment of gait variables defining pelvic and lower limb joint motion and ground reaction forces (GRF). Both groups had an asymmetrical gait pattern with a different magnitude and relative position in the gait cycle, which was revealed by SF. The differences in terms of median, minimum, and maximum were statistically significant (p < 0.05), with SF ranging from −25 to 24% for the AC group and from 43 to 77% (59% on average) for the NAC group. The AC’s pattern was more symmetrical compared to the NAC’s pattern, especially in the case of pelvic and hip joint motion.

Osteoarthritis Flares

The phenomenon of flares is a common feature in the daily life of people with osteoarthritis (OA). Characterized by episodes of sudden-onset increases in signs and symptoms, their impact can often be distressing and disabling. Despite their potential to have both short-term and long-term consequences for patients across the whole course of the condition, their occurrence and optimal management are not fully understood. This article provides a contemporary perspective on defining OA flares and their potential triggers, and offers suggestions for how health professionals might explore flare patterns with patients in clinical practice and frame timely best-practice treatment approaches.

Proposed Canadian Consensus Guidelines on Osteoarthritis Treatment Based on OA-COAST Stages 1–4

The Canadian consensus guidelines on OA treatment were created from a diverse group of experts, with a strong clinical and/or academic background in treating OA in dogs. The document is a summary of the treatment recommendations made by the group, with treatments being divided into either a core or secondary recommendation. Each treatment or modality is then summarized in the context of available research based support and clinical experience, as the treatment of OA continues to be a multimodal and commonly a multidisciplinary as well as individualized approach. The guidelines aim to help clinicians by providing clear and clinically relevant information about treatment options based on COAST defined OA stages 1–4.

Arthrose: Aktivitätsbezogene Belastungen lösen häufig Schub im Knie aus

Schübe mit Schmerzen können für Patienten mit Arthrose belastend sein und die Lebensqualität beeinträchtigen. Zudem führen sie häufig zu Arbeitsausfällen und einer erhöhten Inanspruchnahme des Gesundheitswesens. Ein fundiertes Verständnis der Ursachen von Krankheitsschüben ist für Patienten und Ärzte wichtig, um die Auswirkungen zu verhindern oder zu minimieren. Thomas et al. identifizierten konsistente Auslöser für Arthrose-Schübe im Knie.

Short-term pain trajectories in patients with knee osteoarthritis

AIM

It is unknown if pain in knee osteoarthritis (KOA) follows distinct patterns over the short term. Therefore, the aim of this study was to identify whether persons with a previous history of KOA pain fluctuations have distinct trajectories of pain over 90 days and to examine associations between baseline characteristics and pain trajectories.

METHOD

People with a previous history of KOA were selected from a web-based longitudinal study. Baseline variables were sex, age, being obese/overweight, years of KOA, knee injury, knee buckling, satisfactory Lubben Social Support Score, pain and stress scales, Intermittent Constant Osteoarthritis Pain Score (ICOAP), medication use, and physical activity. Participants completed a Knee Injury and Osteoarthritis Outcomes Score (KOOS) pain subscale (KOOS-p, rated 0 = extreme to 100 = no knee problems) at 10-day intervals for 90 days. Short-term KOOS-p trajectories were identified using latent growth mixture modeling and the baseline risk factors for these pain trajectories were examined.

RESULTS

Participants (n = 313) had a mean age of 62.2 (SD ± 8.1) years and and a body mass index of 29.8 (SD ± 6.6) kg/m² . The three-class latent growth mixture modeling quadratic model with best fit indices was chosen (based on lowest sample-size-adjusted Bayesian Information Criterion, high probability of belonging, interpretability). Three distinct pain trajectory clusters (over 90 days) were identified: low-moderate pain at baseline with large improvement (n = 11), minimal change in pain over 90 days (n = 248), and moderate-high pain with worsening (n = 46). Higher ICOAP (intermittent scale), perceived stress, negative affect score, and knee buckling at baseline were associated with a worse knee pain trajectory (P < 0.05).

CONCLUSIONS

Persons with KOA showed unique short-term pain trajectories over 90 days, with distinct characteristics at baseline associated with each trajectory.