Clinical classification criteria for knee osteoarthritis: performance in the general population and primary care

Prevalence of symptomatic hip and knee osteoarthritis: a two-phase population-based survey

OBJECTIVE

Osteoarthritis (OA) epidemiologic data are scarce in Europe. To estimate the prevalence of symptomatic knee and hip OA in a multiregional sample in France.

DESIGN

A two-phase population-based survey was conducted in six regions in 2007-2009. On initial phone contact using random-digit dialing, subjects 40-75 years old were screened with a validated questionnaire. Subjects screened positive were invited for ascertainment: physical examination and hip and/or knee radiography (Kellgren-Lawrence grade≥2). Multiple imputation for data missing not-at-random was used to account for refusals.

RESULTS

Of 63,232 homes contacted, 27,632 were eligible, 9621 subjects screened positive, 3707 participated fully in the ascertainment phase, and 1010 had symptomatic OA: 317 hip, 756 knee. Hip OA prevalence according to age class ranged from 0.9% to 3.9% for men and 0.7-5.1% for women. Knee OA ranged from 2.1% to 10.1% for men and 1.6-14.9% for women. Both differed by geographical region. The hip and knee standardized prevalence was 1.9% and 4.7% for men and 2.5% and 6.6% for women, respectively.

CONCLUSIONS

This confirmed the feasibility of using a screening questionnaire for eliciting population-based estimates of OA. In France, it increases with age and is greater among women above the age of 50. The geographical disparity of hip and knee OA parallels the distribution of obesity. Study registration ID number 906297 at http://www.clinicaltrials.gov/.

An overview of OA research in two urban APLAR populations

Osteoarthritis (OA), the most prevalent type of arthritis in the elderly, is also among the first five leading causes of disability in developed countries. With the 'Westernized' living environment and lifestyle among Southeast Asian urbanized cities, where obesity is on the rise and the populations are ageing, the incidence of OA is expected to rise in the next decades. There is need to summarize research work within these places. This article summarizes some of the research aspects of OA in Southeast Asian cities. These data may form a useful basis for future planning of medical resource and needs.

[Inflammation in knee osteoarthrosis--cause of aggravation]

INTRODUCTION

Knee osteoarthrosis is a degenerative disease which induces intense trouble.

MATERIAL AND METHODS

The aim of the study was the parallel analysis of clinical and ultrasound examination in patients diagnosed with knee osteoarthrosis. A group of 88 patients underwent the clinical examination and the outflow and size of flexion were determined, the intensity of pain was assessed by the patient's mark on VAS, the functional ability by HAQ index, and the size of effusion and synovitis by arthrosonography.

RESULTS

The minimal outflow was diagnosed in 34.1% of patients, medium in 22.7%, and significant in 4.5%. Synovitis was evident in 67% of patients, 17.0% had nodular, 30.7% diffuse and 19.3% nodular-diffuse type. Effusion was observed in 75% of patients. The average size of synovitis in suprapatellar recess (SR) in the patients with significant, medium and lateral outflow was 6.68 (2.93-10.04) mm (p = 0.000), 1.57 (0-5.53) mm (p = 0.006) and 6.18 (3.44-7.10) mm (p = 0.000), respectively. The grade of pain on VAS was the highest in patients with significant outflow 70 (60-95) (p = 0.014), effusion 60 (50-80) (p = 0.024) and nodular type of synovitis 70 (50-90) (p = 0.029). There was a significant correlation on VAS in the positive direction with the size of effusion (r = 0.238, p = 0.025) and synovitis in LR (r = 0.215, p = 0.044), HAQ index (r = 0.502, p = 0.000), and in the negative direction with the size of flexion (r = -0.346, p = 0.001). The average size of flexion in the patients with significant outflow was 90 (82.5-90) degrees (p = 0.000), HAQ index 1.99 (1.49-2.30) (p = 0.078). HAQ index depended on effusion in LR in the positive direction (p = 0.014).

DISCUSSION AND CONCLUSION

Clinically significant outflow is shown by arthrosonography as the biggest in SR, moderate and minimal only in LR. Moderate or significant outflow, effusion and nodular type of synovitis lead to intensive pain. Patients with bigger functional disability had intense pain, significant outflow in LR and significantly limited motions.

Recommendations for standardization and phenotype definitions in genetic studies of osteoarthritis: the TREAT-OA consortium

OBJECTIVE

To address the need for standardization of osteoarthritis (OA) phenotypes by examining the effect of heterogeneity among symptomatic (SOA) and radiographic osteoarthritis (ROA) phenotypes.

METHODS

Descriptions of OA phenotypes of the 28 studies involved in the TREAT-OA consortium were collected. We investigated whether different OA definitions result in different association results by creating various hip OA definitions in one large population based cohort (the Rotterdam Study I (RSI)) and testing those for association with gender, age and body mass index using one-way ANOVA. For ROA, we standardized the hip-, knee- and hand ROA definitions and calculated prevalence's of ROA before and after standardization in nine cohort studies. This procedure could only be performed in cohort studies and standardization of SOA definitions was not feasible at this moment.

RESULTS

In this consortium, all studies with SOA phenotypes (knee, hip and hand) used a different definition and/or assessment of OA status. For knee-, hip- and hand ROA five, four and seven different definitions were used, respectively. Different hip ROA definitions do lead to different association results. For example, we showed in the RSI that hip OA defined as "at least definite joint space narrowing (JSN) and one definite osteophyte" was not associated with gender (P =0.22), but defined as "at least one definite osteophyte" was significantly associated with gender (P=3×10(-9)). Therefore, a standardization process was undertaken for ROA definitions. Before standardization a wide range of ROA prevalence's was observed in the nine cohorts studied. After standardization the range in prevalence of knee- and hip ROA was small.

CONCLUSION

Phenotype definitions influence the prevalence of OA and association with clinical variables. ROA phenotypes within the TREAT-OA consortium were standardized to reduce heterogeneity and improve power in future genetics studies.

Development of a questionnaire for identification of the risk factors for osteoarthritis of the knees in developing countries. A pilot study in Iran and Bangladesh. An ILAR-COPCORD phase III study

BACKGROUND

Knee osteoarthritis (OA) is one of the most prevalent rheumatic disorders in the Asia-Pacific region. Identification of modifiable risk factors is important for development of strategies for primary and secondary prevention of knee OA.

OBJECTIVE

Developing a core questionnaire for identification of risk factors of knee OA at the community level.

METHODS

Steps performed: (1) item generation from literature, existing knee OA questionnaires and patient focus group discussions; (2) development of a preliminary APLAR-COPCORD English questionnaire; (3) translation into target language, back translation and development of a pre-final target language version; (4) adaptation of the pre-final target language version through tests of comprehensibility, content validity, test-retest reliability; and (5) finalization of the English questionnaire. Investigators in Bangladesh, Iran, China, Philippines and Indonesia participated in steps 1 and 2. Subsequent steps were carried out by Bangladeshi and Iranian investigators.

RESULTS

Fifty-three items were generated. Fourteen were obtainable from physical examination and placed in an examination sheet. Two radiological items were not included. A preliminary English questionnaire comprising the remaining 37 items was constructed and translated into Bengali and Persian. The preliminary Bengali and Persian versions were adapted as a result of tests of comprehensibility, content validity and test-retest reliability. The English questionnaire was adapted through repeated exchange of ideas and experiences among participating investigators. A 35-item English core questionnaire was finally developed.

CONCLUSION

The questionnaires may be used to identify risk factors of knee OA in Asia-Pacific communities after validation and further adaptation. From these data strategies for primary and secondary prevention of knee OA can be developed.

Knee function and prevalence of knee osteoarthritis after anterior cruciate ligament reconstruction: a prospective study with 10 to 15 years of follow-up

BACKGROUND

Few prospective long-term studies of more than 10 years have reported changes in knee function and radiologic outcomes after anterior cruciate ligament (ACL) reconstruction.

PURPOSE

To examine changes in knee function from 6 months to 10 to 15 years after ACL reconstruction and to compare knee function outcomes over time for subjects with isolated ACL injury with those with combined ACL and meniscal injury and/or chondral lesion. Furthermore, the aim was to compare the prevalence of radiographic and symptomatic radiographic knee osteoarthritis between subjects with isolated ACL injuries and those with combined ACL and meniscal and/or chondral lesions 10 to 15 years after ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Follow-up evaluations were performed on 221 subjects at 6 months, 1 year, 2 years, and 10 to 15 years after ACL reconstruction with bone-patellar tendon-bone autograft. Outcome measurements were KT-1000 arthrometer, Lachman and pivot shift tests, Cincinnati knee score, isokinetic muscle strength tests, hop tests, visual analog scale for pain, Tegner activity scale, and the Kellgren and Lawrence classification.

RESULTS

One hundred eighty-one subjects (82%) were evaluated at the 10- to 15-year follow-up. A significant improvement over time was revealed for all prospective outcomes of knee function. No significant differences in knee function over time were detected between the isolated and combined injury groups. Subjects with combined injury had significantly higher prevalence of radiographic knee osteoarthritis compared with those with isolated injury (80% and 62%, P = .008), but no significant group differences were shown for symptomatic radiographic knee osteoarthritis (46% and 32%, P = .053).

CONCLUSION

An overall improvement in knee function outcomes was detected from 6 months to 10 to 15 years after ACL reconstruction for both those with isolated and combined ACL injury, but significantly higher prevalence of radiographic knee osteoarthritis was found for those with combined injuries.

Diagnostic Modalities for Diseased Articular Cartilage-From Defect to Degeneration: A Review

The progression of cartilage matrix damage to generalized degeneration is associated with specific pathophysiological and clinical aspects. Reliable detection of stage-related characteristics of cartilage disease serves both a therapeutic and prognostic goal. Over the past years, several (pre)clinical diagnostic modalities for cartilage pathologies have been advocated. Each modality focuses on different aspects of the disease. Early diagnosis, before irreversible damage has occurred, opens up the possibility for better treatment and improves the patients' prognosis. This article gives an overview of the diagnostic modalities available for monitoring cartilage pathology and focuses on reliability, clinical value, current status, and possible applications.

Characteristics of subjects self-reporting arthritis in a population health survey: distinguishing between types of arthritis

OBJECTIVES

Arthritis is a broad term covering disparate diseases with varying prognoses. Epidemiological surveys are important tools for arthritis research, but they either fail to specify arthritis subtypes or they provide self-reported arthritis data that are potentially misclassified. This limits their use for research about arthritis subgroups. This study describes and compares characteristics of subjects self-reporting subtypes of arthritis in a Canadian epidemiological survey. We also consider the feasibility of developing methods for distinguishing subtypes of arthritis in such population surveys.

METHODS

Using data from 119,904 adult participants in the Canadian Community Health Survey (CCHS) cycle 3.1, we identified those self-reporting one of four subtypes of arthritis and compared the four groups with regard to socio-demographic status, lifestyle and health characteristics, medication use, health care utilization and functional outcomes. Cross-tabulations of weighted prevalence were estimated and tested for statistical significance using the chi-square test.

RESULTS

Descriptive results showed very few distinguishing characteristics across self-reported arthritis subtypes on 34 investigated variables. Participants with osteoarthritis were more likely to be older and female than other groups. Statistical testing showed no difference between rheumatoid arthritis, osteoarthritis and "other" type of arthritis for physical activity level, health conditions, medication use, health care utilization and functional limitations.

DISCUSSION

Characteristics of subjects who self-report different types of arthritis in a typical population health survey (CCHS) are not sufficiently dissimilar to justify valid data analyses and interpretation by arthritis subgroup. Future studies might focus on identifying and implementing supplemental questionnaire items in epidemiological population surveys.

Pre-radiographic MRI findings are associated with onset of knee symptoms: the most study

OBJECTIVE

Magnetic resonance imaging (MRI) has greater sensitivity to detect osteoarthritis (OA) damage than radiographs but it is uncertain which MRI findings in early OA are clinically important. We examined MRI abnormalities detected in knees without radiographic OA and their association with incident knee symptoms.

METHOD

Participants from the Multicenter Osteoarthritis Study (MOST) without frequent knee symptoms (FKS) at baseline were eligible if they also lacked radiographic features of OA at baseline. At 15 months, knees that developed FKS were defined as cases while control knees were drawn from those that remained without FKS. Baseline MRIs were scored at each subregion for cartilage lesions (CARTs); osteophytes (OST); bone marrow lesions (BML) and cysts. We compared cases and controls using marginal logistic regression models, adjusting for age, gender, race, body mass index (BMI), previous injury and clinic site.

RESULTS

36 case knees and 128 control knees were analyzed. MRI damage was common in both cases and controls. The presence of a severe CART (P=0.03), BML (P=0.02) or OST (P=0.02) in the whole knee joint was more common in cases while subchondral cysts did not differ significantly between cases and controls (P>0.1). Case status at 15 months was predicted by baseline damage at only two locations; a BML in the lateral patella (P=0.047) and at the tibial subspinous subregions (P=0.01).

CONCLUSION

In knees without significant symptoms or radiographic features of OA, MRI lesions of OA in only a few specific locations preceded onset of clinical symptoms and suggest that changes in bone play a role in the early development of knee pain. Confirmation of these findings in other prospective studies of knee OA is warranted.

The prognostic value of the clinical ACR classification criteria of knee osteoarthritis for persisting knee complaints and increase of disability in general practice

OBJECTIVE

To assess the prognostic value of the clinical American College of Rheumatism (ACR) classification criteria of knee osteoarthritis (OA) on persisting knee complaints and increase of disability in adult patients with knee pain in general practice after 1-year follow-up.

METHODS

Patients (aged >35 years) consulting for non-traumatic knee complaints in general practice were enrolled in the study. At baseline and 1-year follow-up knee complaints and function were assessed by questionnaires and a physical examination was performed. The prognostic value of fulfilling the clinical ACR criteria of knee OA at baseline on the outcomes persisting knee complaints and increase of disability was determined.

RESULTS

549 patients were included in the study of which 480 (87.4%) were available for follow-up. The studied population consisted of 236 (49.2%) women with mean age 53.6 [standard deviation (sd) 11.3], mean body mass index (BMI) 27.1 (sd 4.2), 288 (60.0%) patients had payed employment, and 292 (60.8%) patients fulfilled the clinical ACR criteria of knee OA. After 1-year follow-up, 236 (49.2%) patients reported persisting knee complaints, and 84 (17.5%) reported an increase of disability. There was no association of fulfilling the clinical ACR criteria of knee OA at baseline with persisting knee complaints [odds ratio (OR) 1.15; 95% Confidence Interval (CI) 0.80; 1.67] or increase of disability (OR 1.05; 95% CI 0.43; 2.58) at follow-up.

CONCLUSION

The clinical ACR classification criteria of knee OA have no prognostic value for predicting persisting knee complaints or an increase of disability at 1-year of follow-up in adult patients with non-traumatic knee complaints in GP.

Long-term clinical benefits and costs of an integrated rehabilitation programme compared with outpatient physiotherapy for chronic knee pain

BACKGROUND

Chronic knee pain is a major cause of disability in the elderly. Management guidelines recommend exercise and self-management interventions as effective treatments. The authors previously described a rehabilitation programme integrating exercise and self-management [Enabling Self-management and Coping with Arthritic knee Pain through Exercise (ESCAPE-knee pain)] that produced short-term improvements in pain and physical function, but sustaining these improvements is difficult. Moreover, the programme is untried in clinical environments, where it would ultimately be delivered.

OBJECTIVES

To establish the feasibility of ESCAPE-knee pain and compare its clinical effectiveness and costs with outpatient physiotherapy.

DESIGN

Pragmatic, randomised controlled trial.

SETTING

Outpatient physiotherapy department and community centre.

PARTICIPANTS

Sixty-four people with chronic knee pain.

INTERVENTIONS

Outpatient physiotherapy compared with ESCAPE-knee pain.

OUTCOMES

The primary outcome was physical function assessed using the Western Ontario and McMaster Universities Osteoarthritis Index. Secondary outcomes included pain, objective functional performance, anxiety, depression, exercise-related health beliefs and healthcare utilisation. All outcomes were assessed at baseline and 12 months after completing the interventions (primary endpoint). ANCOVA investigated between-group differences.

RESULTS

Both groups demonstrated similar improvements in clinical outcomes. Outpatient physiotherapy cost pound 130 per person and the healthcare utilisation costs of participants over 1 year were pound 583. The ESCAPE-knee pain programme cost pound 64 per person and the healthcare utilisation costs of participants over 1 year were pound 320.

CONCLUSIONS

ESCAPE-knee pain can be delivered as a community-based integrated rehabilitation programme for people with chronic knee pain. Both ESCAPE-knee pain and outpatient physiotherapy produced sustained physical and psychosocial benefits, but ESCAPE-knee pain cost less and was more cost-effective.

Physician diagnosed arthritis, reported arthritis and radiological non-axial osteoarthritis

OBJECTIVE

To determine the question that best predicts radiographic evidence of non-axial osteoarthritis (OA).

DESIGN

The Melbourne Women's Mid-life Health Project (MWMHP), commenced in 1991, is a population-based prospective study of 438 Australian-born. Two hundred and fifty-seven (57%) women remained in longitudinal assessment in 2002 and 224 (87%) women agreed to undergo X-rays of their hands and knees between 2002 and 2003.

METHODS

Annually participants were asked about aches and stiff joints and arthritis or rheumatism. In the eleventh year of follow-up X-rays were scored for evidence of OA using a validated scale, by two investigators who were blinded to questionnaire results. Information on hormone therapy use, physical activity, mood, smoking, body mass index (BMI) and age were obtained by both self-administered and face-to-face questionnaires.

RESULTS

Patient reported physician diagnosed arthritis was the best predictor of radiological OA (ROA). The question had a specificity of 64%, a positive predictive value of 57% and a negative predictive value of 71%. Even the most reliable question about arthritis still had a relatively low specificity for radiologically diagnosed OA. Reporting symptoms were significantly more common in participants who were depressed, those who had a higher negative affect and those with a higher BMI.

CONCLUSION

In large epidemiological studies where questionnaire assessment of OA is required, the greatest accuracy is achieved by asking about physician diagnosed arthritis. Concurrent application of a validated scale for mood is important.

Gender difference in symptomatic radiographic knee osteoarthritis in the Knee Clinical Assessment--CAS(K): a prospective study in the general population

Background

A recent study of adults aged ≥50 years reporting knee pain found an excess of radiographic knee osteoarthritis (knee ROA) in symptomatic males compared to females. This was independent of age, BMI and other clinical signs and symptoms. Since this finding contradicts many previous studies, our objective was to explore four possible explanations for this gender difference: X-ray views, selection, occupation and non-articular conditions.

Methods

A community-based prospective study. 819 adults aged ≥50 years reporting knee pain in the previous 12 months were recruited by postal questionnaires to a research clinic involving plain radiography (weight-bearing posteroanterior semiflexed, supine skyline and lateral views), clinical interview and physical examination. Any knee ROA, ROA severity, tibiofemoral joint osteoarthritis (TJOA) and patellofemoral joint osteoarthritis (PJOA) were defined using all three radiographic views. Occupational class was derived from current or last job title. Proportions of each gender with symptomatic knee ROA were expressed as percentages, stratified by age; differences between genders were expressed as percentage differences with 95% confidence intervals.

Results

745 symptomatic participants were eligible and had complete X-ray data. Males had a higher occurrence (77%) of any knee ROA than females (61%). In 50–64 year olds, the excess in men was mild knee OA (particularly PJOA); in ≥65 year olds, the excess was both mild and moderate/severe knee OA (particularly combined TJOA/PJOA). This male excess persisted when using the posteroanterior view only (64% vs. 52%). The lowest level of participation in the clinic was symptomatic females aged 65+. Within each occupational class there were more males with symptomatic knee ROA than females. In those aged 50–64 years, non-articular conditions were equally common in both genders although, in those aged 65+, they occurred more frequently in symptomatic females (41%) than males (31%).

Conclusion

The excess of knee ROA among symptomatic males in this study seems unlikely to be attributable to the use of comprehensive X-ray views. Although prior occupational exposures and the presence of non-articular conditions cannot be fully excluded, selective non-participation bias seems the most likely explanation. This has implications for future study design.

The contribution of selected non-articular conditions to knee pain severity and associated disability in older adults

OBJECTIVE

To estimate the contribution of selected non-articular conditions (NACs) to pain severity and functional limitation in community-dwelling older adults with knee pain.

DESIGN

Population-based, cross-sectional study of 745 adults aged 50 years and over with knee pain. Self-complete questionnaires, clinical history and physical examination were used to identify the presence of selected NACs that could cause pain around the knee. Regression analyses were used to compare levels of knee pain severity (0-20) and functional limitation (0-68) (Western Ontario and McMaster Universities osteoarthritis index physical function subscale [WOMAC-PF]), between those with one or more NACs and those with none (NACs-absent).

RESULTS

Two hundred and seventy-three (36.6%) participants had at least one NAC: widespread pain, n=159; low back pain with index leg referral, n=102; full-leg pain, n=88; hip arthritis, n=65; prepatellar, infrapatellar or pes anserine bursitis, n=35. The NACs group had significantly higher levels of pain severity and functional limitation than the NACs-absent group: 8.2(+/-4.6) vs 5.4(+/-3.8) and 27.9(+/-15.8) vs 16.8(+/-13.2), respectively. The groups did not differ with respect to severity of radiographic osteoarthritis (ROA). Having one or more NACs accounted for a significant proportion of the variance in WOMAC scores, above that which could be explained by age, gender, body mass index and severity of ROA.

CONCLUSION

NACs appear to be common in older adults with knee pain. They make a significant contribution to knee pain severity and functional limitation and are likely to represent additional, rather than alternative, causes of knee pain/functional limitation to osteoarthritis (OA). These factors should be taken into account in epidemiological studies of knee pain and OA.

Knee Images Digital Analysis (KIDA): a novel method to quantify individual radiographic features of knee osteoarthritis in detail

OBJECTIVE

Radiography is still the golden standard for imaging features of osteoarthritis (OA), such as joint space narrowing, subchondral sclerosis, and osteophyte formation. Objective assessment, however, remains difficult. The goal of the present study was to evaluate a novel digital method to analyse standard knee radiographs.

METHODS

Standardized radiographs of 20 healthy and 55 OA knees were taken in general practise according to the semi-flexed method by Buckland-Wright. Joint Space Width (JSW), osteophyte area, subchondral bone density, joint angle, and tibial eminence height were measured as continuous variables using newly developed Knee Images Digital Analysis (KIDA) software on a standard PC. Two observers evaluated the radiographs twice, each on two different occasions. The observers were blinded to the source of the radiographs and to their previous measurements. Statistical analysis to compare measurements within and between observers was performed according to Bland and Altman. Correlations between KIDA data and Kellgren & Lawrence (K&L) grade were calculated and data of healthy knees were compared to those of OA knees.

RESULTS

Intra- and inter-observer variations for measurement of JSW, subchondral bone density, osteophytes, tibial eminence, and joint angle were small. Significant correlations were found between KIDA parameters and K&L grade. Furthermore, significant differences were found between healthy and OA knees.

CONCLUSION

In addition to JSW measurement, objective evaluation of osteophyte formation and subchondral bone density is possible on standard radiographs. The measured differences between OA and healthy individuals suggest that KIDA allows detection of changes in time, although sensitivity to change has to be demonstrated in long-term follow-up studies.

Classification criteria in rheumatic diseases: a review of methodologic properties

OBJECTIVE

To identify classification criteria for the rheumatic diseases and to evaluate their measurement properties and methodologic rigor using current measurement standards.

METHODS

We performed a systematic review of published literature and evaluated criteria sets for stated purpose, derivation and validation sample characteristics, methods of criteria generation and reduction, and consideration of validity, and reliability.

RESULTS

We identified 47 classification criteria sets encompassing 13 conditions. Approximately 50% of the criteria sets were developed based on expert opinion rather than patient data. Of the 47 criteria sets, control samples were derived from patients with rheumatic disease in 15 (32%) sets, from patients with nonrheumatic diseases in 4 (9%) sets, and from healthy participants in 2 (4%) sets. Where patient data were used, the number of cases ranged from 20-588 and the number of controls from 50-787. In only 1 (2%) criteria set was there a distinct separation between investigators who derived the criteria set and clinicians who provided cases and controls. Authors commented on the need for individual criterion to be reliable in 5 (11%) sets, precise in 5 (11%) sets; authors noted the importance of content validity in 12 (26%) sets, and construct validity in 12 (26%) sets.

CONCLUSION

The variation in methodologic rigor used in sample selection affects the validity and reliability of the criteria sets in different clinical and research settings. Despite potential deficiencies in the methods used for some criteria development, the sensitivity and specificity of many criteria sets is moderate to strong.

Knee osteoarthritis in community-dwelling older adults: are there characteristic patterns of pain location?

OBJECTIVE

To determine whether there are characteristic patterns of pain location associated with knee osteoarthritis (OA) among community-dwelling older adults.

DESIGN

Population-based, cross-sectional survey of 697 adults aged 50 years and over reporting knee pain within the past 6 months. Pain at 13 individual sites at or around the knee was coded. Pain locations in participants with and without "symptomatic knee OA" (defined as symptoms on most days in the past month, at least a definite osteophyte on plain X-ray, and current pain intensity of at least 2 out of 10) were compared. Participants were then grouped by pattern of knee pain location, and their clinical and radiographic characteristics compared.

RESULTS

Generalised knee pain (n=313) and medial knee pain (either in isolation or with peripatellar or lateral knee pain: n=175) were the most common patterns. Medial knee pain and distally radiating pain were significantly more likely in those with symptomatic knee OA. Individuals with generalised knee pain with radiation had more persistent, severe pain, and a relatively high proportion had moderate or severe radiographic disease.

CONCLUSION

No single pattern of pain location is pathognomonic for knee OA. Attention towards the role of peripheral nociception and central sensitisation in producing medial knee pain and distally radiating knee pain is warranted.