Prevalence of reported knee pain over twelve years in a community-based cohort

Evaluation of the Diagnostic Performance of American College of Rheumatology, EULAR, and National Institute for Health and Clinical Excellence Criteria Against Clinically Relevant Knee Osteoarthritis: Data From the CHECK Cohort

OBJECTIVE

Our objective was to evaluate the diagnostic performance of the EULAR, American College of Rheumatology (ACR), and National Institute for Health and Care Excellence (NICE) criteria by using clinical experts' diagnosis of clinically relevant knee osteoarthritis (OA) as the outcome of interest.

METHODS

In a previous study, we recruited clinical experts to evaluate longitudinal (5-, 8-, and 10-year follow-up) clinical and radiographic data of symptomatic knees from the Cohort Hip and Cohort Knee (CHECK) study for the presence or absence of clinically relevant OA. In the current study, ACR, EULAR, and NICE criteria were applied to the same 5-, 8-, and 10-year follow-up data; then a knee was diagnosed with OA if fulfilling the criteria at one of the three time points (F1), two of the time points (F2), or at all three time points (F3). Using clinically relevant OA as the reference standard, the sensitivity, specificity, and positive and negative predictive values for the three criteria were assessed.

RESULTS

A total of 539 participants for a total of 833 examined knees were included. Thirty-six percent of knees were diagnosed with clinically relevant OA by experts. Sixty-seven percent to 74% of the knees received the same diagnosis (OA or non-OA) by the three criteria sets for the different definitions (F1 to F3). EULAR consistently (F1 through F3) had the highest specificity, and NICE consistently had the highest sensitivity.

CONCLUSION

The diagnoses only moderately overlapped among the three criteria sets. The EULAR criteria seemed to be more suitable for study enrollment (when aimed at recruiting clinically relevant OA knees), given the highest specificities. The NICE criteria, given the highest sensitivities, could be more useful for an initial diagnosis in clinical practice.

Molecular pathogenesis of OA pain: Past, present, and future

OBJECTIVE

To provide a historical perspective and narrative review on research into the molecular pathogenesis of osteoarthritis pain.

DESIGN

PubMed databases were searched for combinations of "osteoarthritis", "pain" and "animal models" for papers that represented key phases in the history of osteoarthritis pain discovery research including epidemiology, pathology, imaging, preclinical modeling and clinical trials.

RESULTS

The possible anatomical sources of osteoarthritis pain were identified over 50 years ago, but relatively slow progress has been made in understanding the apparent disconnect between structural changes captured by radiography and symptom severity. Translationally relevant animal models of osteoarthritis have aided in our understanding of the structural and molecular drivers of osteoarthritis pain, including molecules such as nerve growth factor and C-C motif chemokine ligand 2. Events leading to persistent osteoarthritis pain appear to involve a two-step process involving changes in joint innervation, including neo-innervation of the articular cartilage, as well as sensitization at the level of the joint, dorsal root ganglion and central nervous system.

CONCLUSIONS

There remains a great need for the development of treatments to reduce osteoarthritis pain in patients. Harnessing all that we have learned over the past several decades is helping us to appreciate the important interaction between structural disease and pain, and this is likely to facilitate development of new disease modifying therapies in the future.

Day-to-day variability of knee pain and the relationship with physical activity in people with knee osteoarthritis: an observational, feasibility study using consumer smartwatches

OBJECTIVE

To assess the feasibility of using smartwatches in people with knee osteoarthritis (OA) to determine the day-to-day variability of pain and the relationship between daily pain and step count.

DESIGN

Observational, feasibility study.

SETTING

In July 2017, the study was advertised in newspapers, magazines and, on social media. Participants had to be living/willing to travel to Manchester. Recruitment was in September 2017 and data collection was completed in January 2018.

PARTICIPANTS

26 participants aged>50 years with self-diagnosed symptomatic knee OA were recruited.

OUTCOME MEASURES

Participants were provided with a consumer cellular smartwatch with a bespoke app that triggered a series of daily questions including two times per day questions about level of knee pain and one time per month question from the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. The smartwatch also recorded daily step counts.

RESULTS

Of the 25 participants, 13 were men and their mean age was 65 years (standard deviation (SD) 8 years). The smartwatch app was successful in simultaneously assessing and recording data on knee pain and step count in real time. Knee pain was categorised into sustained high/low or fluctuating levels, but there was considerable day-to-day variation within these categories. Levels of knee pain in general correlated with pain assessed by KOOS. Those with sustained high/low levels of pain had a similar daily step count average (mean 3754 (SD 2524)/4307 (SD 2992)), but those with fluctuating pain had much lower step count levels (mean 2064 (SD 1716)).

CONCLUSIONS

Smartwatches can be used to assess pain and physical activity in knee OA. Larger studies may help inform a better understanding of causal links between physical activity patterns and pain. In time, this could inform development of personalised physical activity recommendations for people with knee OA.

Factors Associated with Intermittent, Constant, and Mixed Pain in People with Knee Osteoarthritis

Purpose: To explore factors associated with intermittent, constant, and mixed pain in people with knee osteoarthritis. Method: We conducted a secondary analysis of a cross-sectional multicentre study with adults ≥ 40 years with knee osteoarthritis. Participants completed questionnaires on personal (e.g., demographics, comorbidities), physical (e.g., physical function), psychological (e.g., depressive symptoms), pain (e.g., qualities), and tests for physical performance and nervous system sensitivity. We qualified patients' pain as intermittent, constant, or mixed using the Modified painDETECT Questionnaire and assessed associations with the variables using multinomial logistic regression. Results: The 279 participants had an average age of 63.8 years (SD 9.6), BMI of 31.5 kg/m2 (SD 8.7), and 58.6% were female. Older age (odds ratio [OR] 0.95; 95% CI: 0.90, 1.00) and higher self-reported physical function (OR 0.94; 95% CI: 0.91, 0.98) were associated with a lower likelihood of mixed pain compared with intermittent pain. Higher pain intensity (OR 1.25; 95% CI: 1.07, 1.47) was related to a 25% higher likelihood of mixed pain compared with intermittent pain. Conclusions: This study provides initial data for associations of personal, pain, and physical function factors with different pain patterns. Awareness of these factors can help clinicians develop targeted strategies for managing patients' pain.

Progression of chronic pain and associated health-related quality of life and healthcare resource use over 5 years after total knee replacement: evidence from a cohort study

OBJECTIVE

As part of the STAR Programme, a comprehensive study exploring long-term pain after surgery, we investigated how pain and function, health-related quality of life (HRQL), and healthcare resource use evolved over 5 years after total knee replacement (TKR) for those with and without chronic pain 1 year after their primary surgery.

METHODS

We used data from the Clinical Outcomes in Arthroplasty Study prospective cohort study, which followed patients undergoing TKR from two English hospitals for 5 years. Chronic pain was defined using the Oxford Knee Score Pain Subscale (OKS-PS) where participants reporting a score of 14 or lower were classified as having chronic pain 1-year postsurgery. Pain and function were measured with the OKS, HRQL using the EuroQoL-5 Dimension, resource use from yearly questionnaires, and costs estimated from a healthcare system perspective. We analysed the changes in OKS-PS, HRQL and resource use over a 5-year follow-up period. Multiple imputation accounted for missing data.

RESULTS

Chronic pain was reported in 70/552 operated knees (12.7%) 1 year after surgery. The chronic pain group had worse pain, function and HRQL presurgery and postsurgery than the non-chronic pain group. Those without chronic pain markedly improved right after surgery, then plateaued. Those with chronic pain improved slowly but steadily. Participants with chronic pain reported greater healthcare resource use and costs than those without, especially 1 year after surgery, and mostly from hospital readmissions. 64.7% of those in chronic pain recovered during the following 4 years, while 30.9% fluctuated in and out of chronic pain.

CONCLUSION

Although TKR is often highly beneficial, some patients experienced chronic pain postsurgery. Although many fluctuated in their pain levels and most recovered over time, identifying people most likely to have chronic pain and supporting their recovery would benefit patients and healthcare systems.

Scoping Review of Pain and Patient Characteristics and Physical Function Associated with Intermittent and Constant Pain in People with Knee Osteoarthritis

Purpose: We identified the pain and patient characteristics and physical function associated with intermittent and constant pain in people with knee osteoarthritis (OA). Method: The search strategy was conducted in MEDLINE, CINAHL, Embase, SPORTDiscus, Cochrane, and the Physiotherapy Evidence Database for articles published up to October 2018. We included observational studies, randomized controlled trials, reviews, qualitative studies, and case reports in English and French of adults with knee OA. Articles were screened by two independent reviewers, and disagreements were resolved by a third researcher. Results: Our search yielded 1,232 articles, and 4 articles were included in the review. Constant pain was related to limitations in daily activities, a higher Kellgren and Lawrence grade, a higher prevalence of comorbidities, and symptomatic knee OA and depressive symptoms. Intermittent pain was associated with limitations in high-impact activities, but greater time spent in moderate activities was reported. The evidence is contradictory as to whether intermittent or constant pain has a greater average severity. Conclusions: There was limited evidence available to determine the association of pain and patient characteristics and physical function with constant and intermittent pain in people with knee OA. Future research will help improve our understanding of these two pain patterns by examining their associations across a variety of pain and functional outcomes in people with knee OA.

Knee Joint and Quadriceps Dysfunction in Individuals With Anterior Knee Pain, Anterior Cruciate Ligament Reconstruction, and Meniscus Surgery: A Cross-Sectional Study

CONTEXT

While arthrogenous muscle inhibition associated with knee injuries is evident, the relative magnitude of functional deficiency related to each individual knee pathology is unclear.

OBJECTIVE

To compare the knee joint and quadriceps dysfunction among patients with anterior knee pain (AKP) without surgical history and those with surgical history (anterior cruciate ligament reconstruction [ACLR]; meniscus surgery) without current AKP, with matched healthy controls.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PARTICIPANTS

A total of 66 patients with knee pathologies and 30 controls.

MAIN OUTCOME MEASURES

Pain perception and lower-extremity functional outcomes were assessed. Knee joint function was measured by replication tests. Quadriceps function was measured by strength, voluntary activation, and torque-generating capacity.

RESULTS

Patients with AKP reported greater pain perception compared with the other knee conditions (4.3 vs 0.1 of 10 in Numeric Pain Rating Scale, P < .0001). Compared with the controls: (1) patients with AKP showed a greater error on knee-flexion replications at 75° (2.9° vs 5.4°, P = .002), (2) patients with AKP and ACLR showed less quadriceps strength (AKP: 3.3 vs 2.6 N·m/kg, P = .002; ACLR: 3.3 vs 2.7 N·m/kg, P = .02) and voluntary activation (AKP: 0.982 vs 0.928, P < .0001; ACLR: 0.982 vs 0.946, P = .003), and (3) all knee pathologies reported lower scores on functional outcomes (79 vs 65 of 80 points in Lower-Extremity Functional Scale, P < .0001) and showed less quadriceps torque-generating capacity (10.7 vs 7.8 N·m/s/kg, P < .0001). Among the knee pathologies, patients with AKP showed less quadriceps voluntary activation compared with the patients with meniscus surgery (0.928 vs 0.964, P = .03).

CONCLUSION

As patients with AKP had an additional impairment in knee joint flexion replications and reported a less score in functional outcomes, knee pain may produce a greater impact on functional deficiency.

Early knee osteoarthritis prevalence is highest among middle-aged adult females with obesity based on new set of diagnostic criteria from a large sample cohort study in the Japanese general population

PURPOSE

A few new criteria for early detection and prevention of early knee osteoarthritis (EKOA) have been proposed. However, its prevalence, risk factors, relationship with function and prognosis have not been clarified. The purpose of this study was to investigate the prevalence of EKOA and its risk factors in the Japanese general population.

METHODS

A total of 1104 volunteers (443 males, 661 females) who participated in the Iwaki cohort study in Japan were enrolled in this cross-sectional study. Their bilateral weight-bearing anterior-posterior knee radiographs were classified by Kellgren-Lawrence (KL) grade. EKOA (KL grade 0/1) was defined according to the following criteria: knee injury and osteoarthritis outcome score < 85%, joint line tenderness, and crepitus and its prevalence among age-sex groups was calculated. Logistic regression analyses were performed to determine the risk factors for EKOA.

RESULTS

Eight hundred and twenty-two participants had KL grade 0/1, and the EKOA prevalence was 9.5% in males and 15.0% in females (p = 0.011). The prevalence of EKOA increased with age. The highest prevalence was noted in females aged 50-59 years. Logistic regression analysis showed that the risk factors for EKOA were age (p < 0.001, odds ratio (OR) 1.1), female sex (p = 0.002, OR 2.5), high body mass index (p < 0.001, OR 1.2), and history of knee injury (p < 0.001, OR 21.7).

CONCLUSIONS

The highest EKOA prevalence was observed in middle adult females (50-59 years old). The risk factors for EKOA were female sex, ageing, obesity and knee injury history, which were extremely similar to those of definitive knee osteoarthritis.

LEVEL OF EVIDENCE

Level I in diagnostic studies-investigating a diagnostic test.

The clinical and radiographic course of early knee and hip osteoarthritis over 10 years in CHECK (Cohort Hip and Cohort Knee)

OBJECTIVE

To describe the radiographic and symptomatic course in subjects with hip or knee complaints suspected of early osteoarthritis (OA).

DESIGN

CHECK (Cohort Hip and Cohort Knee) is a multicenter, prospective observational cohort study of 1,002 subjects with first complaints in knee(s) and/or hip(s) (age 56 ± 5 years; 79% female; body mass index (BMI) 26 ± 4 kg/m²). Visits took place at baseline and at 2, 5, 8, and 10 year follow-up. At each visit, questionnaires were administered, physical examination performed, and X-ray images obtained. Clinical OA was defined according to the clinical American College of Rheumatism (ACR) criteria. Radiographic OA (ROA) was defined as Kellgren and Lawrence score (K&L) ≥2.

RESULTS

83% of the subjects reported knee pain, 59% hip pain, and 42% reported both hip and knee pain at baseline. 85% of the subjects completed 10-year follow-up. Pain scores remained rather stable over time, although individual scores fluctuated. A total of 138 subjects never fulfilled the clinical American College of Rheumatology (ACR) criteria. 60% (n = 601) had ROA in one or both knees, and 51% (n = 513) had ROA in one or both hips at 10 years. Only 13.5% of the subjects did not develop ROA after 10 years. Most joint replacements (n = 52 (57%)) took place in subjects with multiple affected joints.

CONCLUSIONS

The symptomatic course in subjects with hip or knee complaints suspected of OA remained fairly stable on population level, though individual scores fluctuated. The radiological course was progressive, with joint replacements particularly in subjects with both hip and knee OA.

Trajectories of Quality of Life and Associated Risk Factors in Patients With Knee Osteoarthritis: Findings From the Osteoarthritis Initiative

OBJECTIVE

Knee osteoarthritis (OA) has a significant impact on quality of life (QOL). Although QOL is generally thought to diminish over time, it is unknown whether different patient groups demonstrate unique patterns of change in QOL. We sought to identify and characterize QOL trajectories in knee OA.

DESIGN

This prospective cohort study included 1013 individuals with symptomatic knee OA from the osteoarthritis initiative. We used group-based trajectory modeling to identify distinct temporal patterns of change in the Knee Injury and Osteoarthritis Outcome Score QOL subscale for 8 yrs. Baseline covariates included age, sex, ethnicity, education, co-morbidities, body mass index, substance use, depression, knee pain, and functional tests.

RESULTS

Group-based trajectory modeling revealed the following three distinct QOL trajectories: a high QOL trajectory (32% of the cohort) experiencing improvement for 8 yrs as well as moderate (49%) and low QOL (20%) trajectories maintaining similar levels over time. Low QOL trajectory membership was significantly associated with younger age (P < 0.001), nonwhite race (P < 0.001), less education (P < 0.001), more co-morbidities (P < 0.001), higher body mass index (P < 0.001), and more depressive symptoms (P < 0.001). Higher QOL trajectory members were less likely to undergo knee replacement surgery (P < 0.001).

CONCLUSIONS

Distinct QOL trajectories exist in knee OA and are associated with modifiable factors, with a subset of patients showing potential to improve their QOL over time.

Knee pain in nursing home workers after implementation of a safe resident handling program

PURPOSE

Approximately 25-30% of nursing personnel experience knee pain (KP). We sought to identify physical and psychosocial work exposures, and personal factors related to prevalent, incident, and persistent KP 5-8 years after safe resident handing program (SRHP) implementation in nursing homes.

METHODS

Health and exposure information was obtained from worker surveys 5-6 years ("F5") and 7-8 years ("F6") post-SRHP implementation. Prevalent KP correlates were examined at F5; persistent and incident KP predictors were analyzed at F6, utilizing robust Poisson multivariable regression.

RESULTS

F5 KP prevalence (19.7%) was associated with combined physical exposures, and with either high job strain or low social support, in separate models. Two-year persistent KP was similarly associated with these psychosocial exposures. Being overweight was associated with KP in all analyses.

CONCLUSIONS

The SRHP program did not eliminate knee physical loading, which should be reduced to prevent nursing home worker KP. Workplace psychosocial exposures (high job strain, low social support) also appeared germane.

Effect of a low-intensity, self-management lifestyle intervention on knee pain in community-based young to middle-aged rural women: a cluster randomised controlled trial

Background

Knee pain is common with obesity and weight gain being important risk factors. Previous clinical trials have focused on overweight or obese adults with knee pain and osteoarthritis and demonstrated modest effects of intense weight loss programs on reducing knee pain despite very significant weight loss. There has been no lifestyle intervention that targets community-based adults to test its effect on prevention of knee pain. We aimed to determine the effect of a simple low-intensity self-management lifestyle intervention (HeLP-her), proven in randomised controlled trials to improve lifestyle and prevent weight gain, on knee pain in community-based young to middle-aged rural women.

Methods

A 1-year pragmatic, cluster randomised controlled trial was conducted in 649 community-based women (aged 18–50 years) to receive either the HeLP-her program (consisting of one group session, monthly SMS text messages, one phone coaching session, and a program manual) or one general women’s health education session. Secondary analyses were performed in 390 women who had knee pain measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at baseline and 12-month follow-up. “Any knee pain” was defined as a WOMAC pain score ≥ 1. Knee pain worsening was defined as an increase in WOMAC pain score over 12 months.

Results

Thirty-five percent of women had “any knee pain” at baseline. The risk of knee pain worsening did not differ between the intervention and control groups over 12 months. For women with any knee pain at baseline, those in the intervention arm had a lower risk of knee pain worsening compared with those in the control arm (OR 0.37, 95% CI 0.14–1.01, p = 0.05), with a stronger effect observed in women with body mass index ≥ 25 kg/m² (OR 0.28, 95% CI 0.09–0.87, p = 0.03).

Conclusions

In community-based young to middle-aged women, a simple low-intensity lifestyle program reduced the risk of knee pain worsening in those with any knee pain at baseline, particularly in those overweight or obese. Pragmatic lifestyle programs such as HeLP-her may represent a feasible lifestyle intervention to reduce the burden of knee pain in the community.

Trial registration

ACTRN12612000115831, registered 24 January 2012.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1572-5) contains supplementary material, which is available to authorized users.

Relationship between decreased lower extremity muscle mass and knee pain severity in both the general population and patients with knee osteoarthritis: Findings from the KNHANES V 1-2

Objective

To identify the prevalence of and risk factors for knee pain and radiographic knee osteoarthritis (RKOA) and to investigate the relationship between decreased lower extremity muscle mass (DLEM) and knee pain severity.

Methods

Using data from the Korea National Health and Nutrition Examination Survey, 3,278 participants who were ≥50 years old and who underwent dual x-ray absorptiometry, plain knee radiographs and completed a knee pain questionnaire were enrolled. Lower extremity muscle mass (LEM) was defined as the sum of the fat-free soft tissue mass of the legs, and lower extremity muscle mass index (LMI) was calculated as LEM/body weight (%). DLEM was defined as an LMI more than two standard deviations below the mean of a gender-matched young reference group. Categorical variables were presented as numbers (weighted %).

Results

The prevalence of knee pain and RKOA were 22% (n = 721) and 34.7% (n = 1,234), respectively. Multivariate logistic regression analysis showed being female (OR 2.15, 95% CI 1.67–2.79), older (OR 1.03, 95% CI 1.01–1.04), less educated (OR 1.72, 95% CI 1.09–2.71), stiffness (OR 16.15, 95% CI 12.04–21.66), bed rest (OR 2.49, 95% CI 1.81–3.43), RKOA (OR 2.20, 95% CI 1.78–2.74) and DLEM (OR 1.54, 95% CI 1.09–2.17) were associated with knee pain. Participants with simultaneous RKOA and DLEM complained of more severe pain (pain score 7.18 ± 2.48) than those with knee pain without RKOA or DLEM (5.02 ± 2.44), those with only RKOA (6.29 ± 2.50), or those with only DLEM (6.78 ± 2.18) (P<0.001). These results remained after multivariate analyses of variance (MANOVAs).

Conclusion

The prevalence of knee pain and RKOA were 22% and 34.7%, respectively, in the general Korean population. DLEM was an independent risk factor for knee pain and it was associated with increased pain severity, regardless of RKOA.

Significant pain variability in persons with, or at high risk of, knee osteoarthritis: preliminary investigation based on secondary analysis of cohort data

BACKGROUND

While knee osteoarthritis (OA) is characterised as a slowly progressive disease, acute flares, episodes of severe pain, and substantial fluctuations in pain intensity appear to be part of the natural history for some patients. We sought to estimate what proportion of symptomatic community-dwelling adults might be affected, and to identify patient and problem characteristics associated with higher risk of such variability in pain.

METHODS

We analysed data collected at baseline, 18, 36, 54, and 72 month follow-up of a prospective cohort of symptomatic adults aged over 50 years with current/recent knee pain. At each time point we estimated the proportion of participants reporting 'significant pain variability' (defined as worst pain intensity in the past 6 months ≥5/10 and ≥2 points higher than average pain intensity during the same 6-month period). The associations between significant pain variability and demographic, socioeconomic, lifestyle, clinical, radiographic, and healthcare utilisation factors measured at baseline were estimated by adjusted odds ratios and 95% confidence intervals (aOR; 95%CI) from multivariable discrete-time survival analysis.

RESULTS

Seven hundred and nineteen participants were included in the final analysis. At each time point, 23-32% of participants were classed as reporting significant pain variability. Associated factors included: younger age (aOR (per year): 0.96; 95% CI 0.94, 0.97), higher BMI (per kg/m2:1.03; 1.01, 1.06), higher WOMAC Pain score (per unit: 1.06; 1.03, 1.10), longer time since onset (e.g. 1-5 years vs < 1 year: 1.79; 1.16, 2.75) and morning stiffness (≤30 min vs none: 1.43; 1.10, 1.85). The models accounting for multiple periods of significant symptom variability found similar associations.

CONCLUSIONS

Our findings are consistent with studies showing that, for some patients OA symptoms are significantly variable over time. Future prospective studies on the nature and frequency of flare ups are needed to help determine triggers and their underlying pathophysiology in order to suggest new avenues for effective episode management of OA to complement long-term behaviour change.

Prevention of Incident Knee Osteoarthritis by Moderate Weight Loss in Overweight and Obese Females

OBJECTIVE

This study evaluated the effect of moderate weight loss on the incidence of knee osteoarthritis (OA) in middle-aged overweight and obese women, without clinical and radiologic knee OA at baseline.

METHODS

A total of 353 women (87%) with followup data available were selected from the Prevention of Knee Osteoarthritis in Overweight Females study, which evaluated the preventive effect of a diet and exercise intervention and of oral glucosamine sulfate on the incidence of knee OA. This was an exploratory proof-of-concept analysis, which compared the incidence of knee OA between women who reached the clinically relevant weight loss target of 5 kg or 5% of body weight after 30 months and those who did not reach this target.

RESULTS

The weight loss group showed a significantly lower incidence of knee OA according to the primary outcome measure, which was composed of the American College of Rheumatology criteria (clinical and radiographic), Kellgren/Lawrence grade ≥2, and joint space narrowing ≥1.0 mm (15% versus 20%; odds ratio 0.5, 95% confidence interval 0.3-0.9). Moreover, the weight loss also positively affected several health measures, such as blood glucose level, body fat percentage, and blood pressure.

CONCLUSION

A reduction of ≥5 kg or 5% of body weight over a 30-month period reduces the risk for the onset of radiographic knee OA in middle-aged overweight and obese women. Because of the slow progression of the disease, a longer followup period will be necessary before the number of prevented cases of knee OA by moderate weight loss becomes clinically more relevant.

Longitudinal Course of Physical Function in People With Symptomatic Knee Osteoarthritis: Data From the Multicenter Osteoarthritis Study and the Osteoarthritis Initiative

OBJECTIVE

Pain and functional decline are hallmarks of knee osteoarthritis (OA). Nevertheless, longitudinal studies unexpectedly reveal stable or improved physical function. The aim of this study was to impute missing and pre-total knee replacement (TKR) values to describe physical function over time among people with symptomatic knee OA.

METHODS

We included participants from the Multicenter Osteoarthritis Study (MOST) and the Osteoarthritis Initiative (OAI) with incident symptomatic knee OA, observed during the first 30 months in MOST and 36 months in OAI. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function (WOMAC-PF), the 5-times sit-to-stand test, and the 20-meter-walk test were assessed at 4 and 5 years in MOST and at 6 years in OAI. We used a multiple imputation method for missing visits, and estimated pre-TKR values close to the time of TKR, using a fitted local regression smoothing curve. In mixed-effect models, we investigated the physical function change over time, using data before and after imputation and calculation of pre-TKR values.

RESULTS

In MOST, 225 (8%) had incident knee OA, with corresponding 577 (12.7%) in OAI. After adjusting for pre-TKR values and imputing missing values, we found that WOMAC-PF values remained stable or slightly declined over time, and the 20-meter-walk test results changed from stable in nonimputed analyses to worsening using imputed data.

CONCLUSION

Data from MOST and OAI showed stable to worsening physical function over time in people with incident symptomatic knee OA after imputing missing values and adjusting pre-TKR values.

Can we identify patients with high risk of osteoarthritis progression who will respond to treatment? A focus on epidemiology and phenotype of osteoarthritis

Osteoarthritis is a syndrome affecting a variety of patient profiles. A European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis and the European Union Geriatric Medicine Society working meeting explored the possibility of identifying different patient profiles in osteoarthritis. The risk factors for the development of osteoarthritis include systemic factors (e.g., age, sex, obesity, genetics, race, and bone density) and local biomechanical factors (e.g., obesity, sport, joint injury, and muscle weakness); most also predict disease progression, particularly joint injury, malalignment, and synovitis/effusion. The characterization of patient profiles should help to better orientate research, facilitate trial design, and define which patients are the most likely to benefit from treatment. There are a number of profile candidates. Generalized, polyarticular osteoarthritis and local, monoarticular osteoarthritis appear to be two different profiles; the former is a feature of osteoarthritis co-morbid with inflammation or the metabolic syndrome, while the latter is more typical of post-trauma osteoarthritis, especially in cases with severe malalignment. Other biomechanical factors may also define profiles, such as joint malalignment, loss of meniscal function, and ligament injury. Early- and late-stage osteoarthritis appear as separate profiles, notably in terms of treatment response. Finally, there is evidence that there are two separate profiles related to lesions in the subchondral bone, which may determine benefit from bone-active treatments. Decisions on appropriate therapy should be made considering clinical presentation, underlying pathophysiology, and stage of disease. Identification of patient profiles may lead to more personalized healthcare, with more targeted treatment for osteoarthritis.

Serum cartilage oligomeric matrix protein and development of radiographic and painful knee osteoarthritis. A community-based cohort of middle-aged women

CONTEXT AND OBJECTIVE

We evaluated the predictive value of serum cartilage oligomeric matrix protein (sCOMP) levels over 20 years on the development of radiographic (RKOA) and painful knee osteoarthritis (KOA) in a longitudinal cohort of middle-aged women.

MATERIALS AND METHODS

Five hundred and ninety-three women with no baseline KOA underwent 5-year knee radiographs over 20-years and were asked about knee pain a month before each assessment. A repeated measures logistic regression model was used where the outcomes were recorded at 5, 10, 15 and 20-years follow-up.

RESULTS

The highest quartile of sCOMP was associated with increased risk of RKOA with overall OR of 1.97 (95% CI: 1.33-2.91) over 20 years when compared with the lowest sCOMP quartile. The association with painful KOA was similar and also independent, but only when the fourth and third sCOMP quartiles were compared.

DISCUSSION AND CONCLUSION

This study demonstrates that sCOMP levels are predictive of subsequent structural changes and incidence of painful KOA, independently of age and BMI.

Annual Incidence of Knee Symptoms and Four Knee Osteoarthritis Outcomes in the Johnston County Osteoarthritis Project

OBJECTIVE

To estimate annual incidence rates (IRs) of knee symptoms and 4 knee osteoarthritis (OA) outcomes (radiographic, symptomatic, severe radiographic, and severe symptomatic), overall and stratified by sociodemographic characteristics and knee OA risk factors.

METHODS

We analyzed baseline (1991-1997) and first followup (1999-2003) data (n = 1,518) from the Johnston County Osteoarthritis Project. Participants were African American and white adults, ages ≥45 years, living in Johnston County, North Carolina, US. Knee symptoms were pain, aching, or stiffness on most days in a knee. Radiographic OA was Kellgren/Lawrence grade ≤2 (severe radiographic ≥3) in at least 1 knee. Symptomatic OA was defined as symptoms in a radiographically affected knee; severe symptomatic OA was defined as severe symptoms and severe radiographic OA.

RESULTS

The median followup time was 5.5 years. Average annual IRs were 6% for symptoms, 3% for radiographic OA, 2% for symptomatic OA, 2% for severe radiographic OA, and 0.8% for severe symptomatic OA. Across outcomes, IRs were highest among those with the following baseline characteristics: age ≥75 years, obese, a history of knee injury, or an annual household income ≤$15,000.

CONCLUSION

The annual onset of knee symptoms and 4 OA outcomes in Johnston County was high. This may preview the future of knee OA in the US and underscores the urgency of clinical and public health collaborations that reduce risk factors for, and manage the impact of, these outcomes. Inexpensive, convenient, and proven strategies (e.g., physical activity, self-management education courses) complement clinical care and can reduce pain and improve quality of life for people with arthritis.

Can We Identify Patients with High Risk of Osteoarthritis Progression Who Will Respond to Treatment? A Focus on Biomarkers and Frailty

Osteoarthritis (OA), a disease affecting different patient phenotypes, appears as an optimal candidate for personalized healthcare. The aim of the discussions of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) working group was to explore the value of markers of different sources in defining different phenotypes of patients with OA. The ESCEO organized a series of meetings to explore the possibility of identifying patients who would most benefit from treatment for OA, on the basis of recent data and expert opinion. In the first meeting, patient phenotypes were identified according to the number of affected joints, biomechanical factors, and the presence of lesions in the subchondral bone. In the second meeting, summarized in the present article, the working group explored other markers involved in OA. Profiles of patients may be defined according to their level of pain, functional limitation, and presence of coexistent chronic conditions including frailty status. A considerable amount of data suggests that magnetic resonance imaging may also assist in delineating different phenotypes of patients with OA. Among multiple biochemical biomarkers identified, none is sufficiently validated and recognized to identify patients who should be treated. Considerable efforts are also being made to identify genetic and epigenetic factors involved in OA, but results are still limited. The many potential biomarkers that could be used as potential stratifiers are promising, but more research is needed to characterize and qualify the existing biomarkers and to identify new candidates.

Knee Pain and Low Back Pain Additively Disturb Sleep in the General Population: A Cross-Sectional Analysis of the Nagahama Study

Introduction

Association of knee and low back pain with sleep disturbance is poorly understood. We aimed to clarify the independent and combined effects of these orthopedic symptoms on sleep in a large-scale general population.

Methods

Cross-sectional data about sleep and knee/low back pain were collected for 9,611 community residents (53±14 years old) by a structured questionnaire. Sleep duration less than 6 h/d was defined as short sleep. Sleep quality and the presence of knee and low back pain were evaluated by dichotomous questions. Subjects who complained about knee or low back pains were graded by tertiles of a numerical response scale (NRS) score and a Roland-Morris disability questionnaire (RDQ) score respectively. Multivariate regression analyses were performed to determine the correlates of short sleep duration and poor sleep quality.

Results

Frequency of participants who complained of the orthopedic symptoms was as follows; knee pain, 29.0%; low back pain, 42.0% and both knee and low back pain 17.6%. Both knee and low back pain were significantly and independently associated with short sleep duration (knee pain: odds ratio (OR) = 1.19, p<0.01; low back pain: OR = 1.13, p = 0.01) and poor sleep quality (knee pain: OR = 1.22, p<0.01; low back pain; OR = 1.57, p<0.01). The group in the highest tertile of the NRS or RDQ score had the highest risk for short sleep duration and poor sleep quality except for the relationship between the highest tertile of the RDQ score and short sleep duration.(the highest tertile of the NRS: OR for short sleep duration = 1.31, p<0.01; OR for poor sleep quality = 1.47, p<0.01; the highest tertile of the RDQ: OR for short sleep duration = 1.11, p = 0.12; OR for poor sleep quality = 1.81, p<0.01) Further, coincident knee and low back pain raised the odds ratios for short sleep duration (either of knee or low back pain: OR = 1.10, p = 0.06; both knee and low back pain: OR = 1.40, p<0.01) and poor sleep quality (either of knee or low back pain: OR = 1.61, p<0.01; both knee and low back pain: OR = 2.17, p<0.01).

Conclusion

Knee and low back pains were independently associated with short sleep duration and poor sleep quality. Further, they additively increased the correlation with these sleep problems in the general population.

Pain trajectory groups in persons with, or at high risk of, knee osteoarthritis: findings from the Knee Clinical Assessment Study and the Osteoarthritis Initiative

OBJECTIVE

The authors aimed to characterize distinct trajectories of knee pain in adults who had, or were at high risk of, knee osteoarthritis using data from two population-based cohorts.

METHOD

Latent class growth analysis was applied to measures of knee pain severity on activity obtained at 18-month intervals for up to 6 years between 2002 and 2009 from symptomatic participants aged over 50 years in the Knee Clinical Assessment Study (CAS-K) in the United Kingdom. The optimum latent class growth model from CAS-K was then tested for reproducibility in a matched sample of participants from the Osteoarthritis Initiative (OAI) in the United States.

RESULTS

A 5-class linear model produced interpretable trajectories in CAS-K with reasonable goodness of fit and which were labelled "Mild, non-progressive" (N = 201, 35%), "Progressive" (N = 162, 28%), "Moderate" (N = 124, 22%) "Improving" (N = 68, 12%), and "Severe, non-improving" (N = 15, 3%). We were able to reproduce "Mild, non-progressive", "Moderate", and "Severe, non-improving" classes in the matched sample of participants from the OAI, however, absence of a "Progressive" class and instability of the "Improving" classes in the OAI was observed.

CONCLUSIONS

Our findings strengthen the grounds for moving beyond a simple stereotype of osteoarthritis as "slowly progressive". Mild, non-progressive or improving symptom trajectories, although difficult to reproduce, can nevertheless represent a genuinely favourable prognosis for a sizeable minority.

Osteoarthritis disease progression model using six year follow-up data from the osteoarthritis initiative

The objective was to develop a quantitative model of disease progression of knee osteoarthritis over 6 years using the total WOMAC score from patients enrolled into the Osteoarthritis Initiative (OAI) study. The analysis was performed using data from the Osteoarthritis Initiative database. The time course of the total WOMAC score of patients enrolled into the progression cohort was characterized using non-linear mixed effect modeling in NONMEM. The effect of covariates on the status of the disease and the progression rate was investigated. The final model provided a good description of the experimental data using a linear progression model with a common baseline (19 units of the total WOMAC score). The WOMAC score decreased by 1.77 units/year in 89% of the population or increased by 1.74 units/year in 11% of the population. Multiple covariates were found to affect the baseline and the rate of progression, including BMI, sex, race, the use of pain medications, and the limitation in activity due to symptoms. A mathematical model to describe the disease progression of osteoarthritis in the studied population was developed. The model identified two sub-populations with increasing or decreasing total WOMAC score over time, and the effect of important covariates was quantified.

Prevalence of knee pain, lumbar pain and its coexistence in Japanese men and women: The Longitudinal Cohorts of Motor System Organ (LOCOMO) study

The Longitudinal Cohorts of Motor System Organ (LOCOMO) study was initiated in 2008 through a grant from the Ministry of Health, Labour, and Welfare of Japan to integrate information from several cohorts established for the prevention of musculoskeletal diseases. We integrated the information of 12,019 participants (3,959 men and 8,060 women) in the cohorts comprising nine communities located in Tokyo (two regions: Tokyo-1 and Tokyo-2), Wakayama [two regions: Wakayama-1 (mountainous region) and Wakayama-2 (seaside region)], Hiroshima, Niigata, Mie, Akita, and Gunma prefectures. The baseline examination of the LOCOMO study consisted of an interviewer-administered questionnaire, anthropometric measurements, medical information recording, X-ray radiography, and bone mineral density measurement. The prevalence of knee pain was 32.7 % (men 27.9 %; women 35.1 %) and that of lumbar pain was 37.7 % (men 34.2 %; women 39.4 %). Among the 9,046 individuals who were surveyed on both knee pain and lumbar pain at the baseline examination in each cohort, we noted that the prevalence of both knee pain and lumbar pain was 12.2 % (men 10.9 %; women 12.8 %). Logistic regression analysis showed that higher age, female sex, higher body mass index (BMI), living in a rural area, and the presence of lumbar pain significantly influenced the presence of knee pain. Similarly, higher age, female sex, higher BMI, living in a rural area, and the presence of knee pain significantly influenced the presence of lumbar pain. Thus, by using the data of the LOCOMO study, we clarified the prevalence of knee pain and lumbar pain, their coexistence, and their associated factors.

Study protocol, sample characteristics, and loss to follow-up: the OPPERA prospective cohort study

When studying incidence of pain conditions such as temporomandibular disorder (TMD), repeated monitoring is needed in prospective cohort studies. However, monitoring methods usually have limitations and, over a period of years, some loss to follow-up is inevitable. The OPPERA prospective cohort study of first-onset TMD screened for symptoms using quarterly questionnaires and examined symptomatic participants to definitively ascertain TMD incidence. During the median 2.8-year observation period, 16% of the 3,263 enrollees completed no follow-up questionnaires, others provided incomplete follow-up, and examinations were not conducted for one third of symptomatic episodes. Although screening methods and examinations were found to have excellent reliability and validity, they were not perfect. Loss to follow-up varied according to some putative TMD risk factors, although multiple imputation to correct the problem suggested that bias was minimal. A second method of multiple imputation that evaluated bias associated with omitted and dubious examinations revealed a slight underestimate of incidence and some small biases in hazard ratios used to quantify effects of risk factors. Although "bottom line" statistical conclusions were not affected, multiply-imputed estimates should be considered when evaluating the large number of risk factors under investigation in the OPPERA study.

PERSPECTIVE

These findings support the validity of the OPPERA prospective cohort study for the purpose of investigating the etiology of first-onset TMD, providing the foundation for other papers investigating risk factors hypothesized in the OPPERA project.

Association of knee osteoarthritis with onset and resolution of pain and physical functional disability: the ROAD study

OBJECTIVES

To examine the onset and resolution of pain and physical functional disability using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and their association with knee osteoarthritis (OA) in the longitudinal large-scale population of the nationwide cohort study, Research on Osteoarthritis/osteoporosis Against Disability (ROAD).

METHODS

Subjects from the ROAD study who had been recruited during 2005-2007 were followed up 3 years later. A total of 1,578 subjects completed the WOMAC questionnaire at baseline and follow up, and the onset and resolution rate of pain and physical functional disability were examined. We also examined the association of onset of pain and physical functional disability and their resolution with severity of knee OA as well as age, body-mass index and grip strength.

RESULTS

After a 3.3-year follow-up, the onset rate of pain was 35.0% and 35.3% in men and women, respectively, and the onset rate of physical functional disability was 38% and 40%, respectively. Resolution rate of pain was 20.3% and 26.2% in men and women, respectively, and resolution rate of physical functional disability was 16% and 14% in men and women, respectively. Knee OA was significantly associated with onset and resolution of pain and physical functional disability in women, but there was no significant association of knee OA with onset of pain and resolution of physical functional disability in men.

CONCLUSIONS

The present longitudinal study revealed the onset rate of pain and physical functional disability as well as their resolution, and their association with knee OA.

Neuropathic features of joint pain: a community-based study

OBJECTIVE

Quantitative sensory testing (QST) and questionnaire-based assessments have been used to demonstrate features of neuropathic pain in subjects with musculoskeletal pain. However, their direct relationship has not been investigated in the community. The purpose of this study was to conduct an observational study to describe the characteristics of joint pain and to examine the relationship between QST measures and the PainDETECT Questionnaire (PD-Q).

METHODS

Warm detection, heat pain, and mechanical pain thresholds as well as mechanical pain sensitivity over the sternum were determined and the PD-Q scores were calculated in a cross-sectional study of 462 participants in the Chingford Study. Comparisons were made between subjects with and those without joint pain. Logistic regression modeling was used to describe the association between neuropathic pain features, as determined by the PD-Q score, and each of the QST measures individually, adjusting for age, body mass index, and use of pain-modifying medications.

RESULTS

A total of 66.2% of the subjects reported recent joint pain, with a median average pain severity of 5 of 10. There was increased sensitivity to painful stimuli in the group with pain as compared to the pain-free group, and this persisted after stratification by pain-modifying medication use. While only 6.7% of subjects had possible neuropathic pain features and 1.9% likely neuropathic pain features according to the standard PD-Q thresholds, features of neuropathic pain were common and were present in >50% of those reporting pain of at least moderate severity. Heat pain thresholds and mechanical pain sensitivity were significantly associated with features of neuropathic pain identified using the PD-Q, with an odds ratio (OR) of 0.88 (95% confidence interval [95% CI] 0.79-0.97; P = 0.011) and an OR of 1.24 (95% CI 1.04-1.48; P = 0.018), respectively.

CONCLUSION

QST measures and the PD-Q identified features of neuropathic pain in subjects in this community-based study, with significant overlap between the findings of the two techniques.

How to define responders in osteoarthritis

BACKGROUND

Osteoarthritis is a clinical syndrome of failure of the joint accompanied by varying degrees of joint pain, functional limitation, and reduced quality of life due to deterioration of articular cartilage and involvement of other joint structures.

SCOPE

Regulatory agencies require relevant clinical benefit on symptoms and structure modification for registration of a new therapy as a disease-modifying osteoarthritis drug (DMOAD). An international Working Group of the European Society on Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) and International Osteoporosis Foundation was convened to explore the current burden of osteoarthritis, review current regulatory guidelines for the conduct of clinical trials, and examine the concept of responder analyses for improving drug evaluation in osteoarthritis.

FINDINGS

The ESCEO considers that the major challenges in DMOAD development are the absence of a precise definition of the disease, particularly in the early stages, and the lack of consensus on how to detect structural changes and link them to clinically meaningful endpoints. Responder criteria should help identify progression of disease and be clinically meaningful. The ideal criterion should be sensitive to change over time and should predict disease progression and outcomes such as joint replacement.

CONCLUSION

The ESCEO considers that, for knee osteoarthritis, clinical trial data indicate that radiographic joint space narrowing >0.5 mm over 2 or 3 years might be a reliable surrogate measure for total joint replacement. On-going research using techniques such as magnetic resonance imaging and biochemical markers may allow the identification of these patients earlier in the disease process.

Preclinical episodes of orofacial pain symptoms and their association with health care behaviors in the OPPERA prospective cohort study

The course of preclinical pain symptoms sheds light on the etiology and prognosis of chronic pain. We aimed to quantify rates of developing initial and recurrent symptoms of painful temporomandibular disorder (TMD) and to evaluate associations with health behaviors. In the OPPERA prospective cohort study, 2,719 individuals aged 18 to 44years with lifetime absence of TMD when enrolled completed 25,103 quarterly (3-monthly) questionnaires during a median 2.3-year follow-up period. Questionnaires documented TMD symptom episodes, headache, other body pain, health care attendance, and analgesic use, and. Kaplan-Meier methods for clustered data estimated symptom-free survival time. Multivariable models assessed demographic variation in TMD symptom rates and evaluated associations with health care and analgesic use. One-third of the study subjects developed TMD symptoms and for a quarter of symptomatic episodes, pain intensity was severe. Initial TMD symptoms developed at an annual rate of 18.8 episodes per 100 persons. The annual rate more than doubled for first-recurrence and doubled again for second or subsequent recurrence such that, 1year after first recurrence, 71% of study subjects experienced a second recurrence. The overall rate increased with age and was greater in African Americans and lower in Asians relative to those of white race/ethnicity. The probability of TMD symptoms was strongly associated with concurrent episodes of headache and body pain and with past episodes of TMD symptoms. Episodes of TMD symptoms, headache, and body pain were associated with increases of ∼10% in probability of analgesic use and health care attendance. Yet, even when TMD, headache, and body pain occurred concurrently, 27% of study subjects neither attended health care nor used analgesics.

Effects of phonophoresis of piroxicam and ultrasound on symptomatic knee osteoarthritis

OBJECTIVE

To compare the effects of phonophoresis of piroxicam (PhP) and ultrasound therapy (UT) in patients with mild to moderate, symptomatic knee osteoarthritis (OA).

DESIGN

A randomized, double-blind, controlled trial.

SETTING

Department of rehabilitation medicine, university hospital.

PARTICIPANTS

Patients with knee OA (N=46; mean age ± SD, 58.91±10.50y) who had visual analog scale (VAS) scores of 50 to 92mm (mean, 71.5mm) for knee pain intensity and Kellgren-Lawrence grades of I to III were randomly allocated into 2 groups: PhP and UT (23 in each group).

INTERVENTIONS

Both the PhP and UT groups were treated with an ultrasound program using the stroking technique, continuous mode, 1.0W/cm(2), 10 minutes per session, and 5 times per week for 2 weeks. Four grams of 0.5% piroxicam gel (20mg of piroxicam drug) was used in the PhP group, while the nondrug coupling gel was used in the UT group.

MAIN OUTCOME MEASURES

A 100-mm VAS for usual pain and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were evaluated before and after treatment in both groups using a double-blinded procedure.

RESULTS

The VAS and total WOMAC scores were significantly improved after treatment in both groups (P<.001). The PhP group showed more significant effects than the UT group, both in reducing the VAS pain score (P=.009) and in improving the WOMAC score, although it did not reach the level of significance (P=.143).

CONCLUSIONS

Our results indicated that PhP was significantly more effective than UT in reducing pain and tended to improve knee functioning in Kellgren-Lawrence grades I to III knee OA. PhP is suggested as a new, effective method for treatment of symptomatic knee OA.