A pinboard by
Kai Fu

PhD candidate, University of Sydney


With ageing of the population and increasing obesity, the prevalence of osteoarthritis (OA) is expected to rise, and OA is projected to become the fourth leading cause of disability worldwide by 2020. Hip OA, the second principal large joint to be affected, can result in disabling hip symptoms, and radiographic hip OA is present in approximately one in four individuals older than age 45 years, of which 11.6% require total hip replacement mainly due to disabling pain.

Pain is the dominant symptom in patients with hip OA and a major driver of clinical decision-making. There are two main types of pain in patients with hip or knee OA which include intermittent and intense pain, although relatively little attention was paid to OA pain experience. Effective pain management is of utmost importance for patients with hip OA for its chronic and incurable characteristics.

However, the assessment of hip OA pain remains a challenge as hip pain fluctuates, with each episode of pain lasting from days to weeks depending on many other factors. There are only a few studies which have investigated the relationship between hip pain and the related factors, and there are no studies that have investigated the causes for pain exacerbation in hip OA. If the risk factors for these pain exacerbations could be identified and avoided, many such episodes could be prevented.

We are conducting a study that uses the internet to collect the suitable OA patients and requires them to fill out online questionnaire at different time. The aim of this project is that risk factors for pain exacerbation will be measured by validated instruments and the risk factors could be identified which could be avoided to improve the quality of life for patients with hip OA.


The influence of weather on the risk of pain exacerbation in patients with knee osteoarthritis - a case-crossover study.

Abstract: To quantify the risk of knee pain exacerbation associated with temperature, relative humidity, air pressure and precipitation in persons with knee osteoarthritis.a web-based case-crossover study was conducted. Participants with a diagnosis of symptomatic, radiographic knee osteoarthritis were measured at baseline and followed for 3 months. Participants were instructed to log on to the study website if they perceived experiencing knee pain exacerbation (hazard period). Pain exacerbation was defined as an increase of ≥ 2 on a 0-10 numeric rating scale from the participant's mildest pain reported at baseline. A time-stratified case-crossover study was conducted to anchor the corresponding hazard date to 4 control periods within a particular 35-day interval. Data on maximum and minimum temperature ((o)C), relative humidity (%), barometric pressure (hPa) and precipitation (mm) were obtained for the hazard and control periods from the publicly available meteorological database of the Australian Bureau of Meteorology. The associations were assessed using conditional logistic regression.Of the 345 participants recruited, 171 participants (women: 64%, mean age: 62 years, mean BMI: 30.2 kg/m2) experienced at least one episode of pain exacerbation, yielding 1,425 observations included in the analyses. There was no apparent association between temperature, relative humidity, air pressure or precipitation and risk of knee pain exacerbation.Despite anecdotal reports from patients, change in weather factors does not appear to influence the risk of pain exacerbation in persons with knee osteoarthritis. Additional studies should quantify the association of weather and risk of pain exacerbation in regions with more extreme weather conditions.

Pub.: 06 Aug '16, Pinned: 27 Aug '17

Defining Flare in Osteoarthritis of the Hip and Knee: A Systematic Literature Review - OMERACT Virtual Special Interest Group.

Abstract: Beyond the exacerbation of pain in describing a flare in osteoarthritis (OA), patients and health professionals add other elements that deserve to be fully elucidated, such as effusion, swelling, and mobility limitation. To define and conceptualize the construct flare in OA, the objective was to identify the key variables, or symptoms, that worsen, and to clarify how these variables are described in the literature by patients and clinicians.A systematic review of the literature was conducted in Medline and PsychINFO. In brief, the search terms used were "osteoarthritis," "knee," "hip," and "flare." Specific characteristics of included studies were identified, including the type of study design, type of flare assessed, how the flare developed, and what definition of flare was used, including whether the definition was based on qualitative or quantitative analysis.Pain was the major factor in the definition of flare within these studies. Four components of flare were identified: pain, other factors, composite criteria, and global assessment. While the majority of studies reported flare as an increase in pain using standardized outcome measures, only 1 study reported the antecedents and consequences of a pain flare using qualitative methods.The use of flare as an outcome or inclusion criterion in rheumatology trials is a common occurrence; however, this review highlights the wide variation in the definitions of OA flare currently in use and the emphasis on the measurement of pain. This variation in definition does not allow for direct comparison between trials and limits interpretation of evidence.

Pub.: 03 Jul '17, Pinned: 27 Aug '17

Web-Based Study of Risk Factors for Pain Exacerbation in Osteoarthritis of the Knee (SPARK-Web): Design and Rationale.

Abstract: Knee osteoarthritis (OA) is the most frequent cause of limited mobility and diminished quality of life. Pain is the main symptom that drives individuals with knee OA to seek medical care and a recognized antecedent to disability and eventually joint replacement. Many persons with symptomatic knee OA experience recurrent pain exacerbations. Knowledge and clarification of risk factors for pain exacerbation may allow those affected to minimize reoccurrence of these episodes.The aim of this study is to use a Web-based case-crossover design to identify risk factors for knee pain exacerbations in persons with symptomatic knee OA.Web-based case-crossover design is used to study persons with symptomatic knee OA. Participants with knee pain and radiographic knee OA will be recruited and followed for 90 days. Participants will complete an online questionnaire at the baseline and every 10 days thereafter (totaling up to 10 control-period questionnaires); participants will also be asked to report online when they experience an episode of increased knee pain. Pain exacerbation will be defined as an increase in knee pain severity of two points from baseline on a numeric rating scale (NRS 0-10). Physical activity, footwear, knee injury, medication use, climate, psychological factors, and their possible interactions will be assessed as potential triggers for pain exacerbation using conditional logistic regression models.This project has been funded by the National Health and Medical Research Council (NHMRC). The enrollment for the study has started. So far, 343 participants have been enrolled. The study is expected to be finished in October 2015.This study will identify risk factors for pain exacerbations in knee OA. The identification and possible modification/elimination of such risk factors will help to prevent the reoccurrence of pain exacerbation episodes and therefore improve knee OA management.

Pub.: 15 Jul '15, Pinned: 25 Aug '17

Relationship of Buckling and Knee Injury to Pain Exacerbation in Knee Osteoarthritis: A Web-Based Case-Crossover Study.

Abstract: Knee osteoarthritis (OA) is one of the most frequent causes of limited mobility and diminished quality of life. Pain is the main symptom that drives individuals with knee OA to seek medical care and a recognized antecedent to disability and eventually joint replacement. Evidence shows that patients with symptomatic OA experience fluctuations in pain severity. Mechanical insults to the knee such as injury and buckling may contribute to pain exacerbation.Our objective was to examine whether knee injury and buckling (giving way) are triggers for exacerbation of pain in persons with symptomatic knee OA.We conducted a case-crossover study, a novel methodology in which participants with symptomatic radiographic knee OA who have had knee pain exacerbations were used as their own control (self-matched design), with all data collected via the Internet. Participants were asked to log-on to the study website and complete an online questionnaire at baseline and then at regular 10-day intervals for 3 months (control periods)-a total of 10 questionnaires. They were also instructed to go to the website and complete pain exacerbation questionnaires when they experienced an isolated incident of knee pain exacerbation (case periods). A pain exacerbation "case" period was defined as an increase of ≥2 compared to baseline. At each contact the pain exacerbation was designated a case period, and at all other regular 10-day contacts (control periods) participants were asked about knee injuries during the previous 7 days and knee buckling during the previous 2 days. The relationship of knee injury and buckling to the risk of pain exacerbation was examined using conditional logistic regression models.The analysis included 157 participants (66% women, mean age: 62 years, mean BMI: 29.5 kg/m(2)). Sustaining a knee injury was associated with experiencing a pain exacerbation (odds ratio [OR] 10.2, 95% CI 5.4, 19.3) compared with no injury. Knee buckling was associated with experiencing a pain exacerbation (OR 4.0, 95% CI 2.6, 6.2) compared with no buckling and the association increased with a greater number of buckling events (for ≥ 6 buckling events, OR 20.1, 95% CI 3.7, 110).Knee injury and buckling are associated with knee pain exacerbation. Reducing the likelihood of these mechanical events through avoidance of particular activities and/or appropriate rehabilitation programs may decrease the risk of pain exacerbation.

Pub.: 28 Jun '16, Pinned: 25 Aug '17