Primary care physicians' perceptions about and confidence in deciding which patients to refer for total joint arthroplasty of the hip and knee.

OBJECTIVE: The purpose of this study is to examine the perceptions of primary care physicians (PCPs) regarding indications, contraindications, risks and benefits of total joint arthroplasty (TJA) and their confidence in selecting patients for referral for TJA. DESIGN: PCPs recruited from among those providing care to participants in an established community cohort with hip or knee osteoarthritis (OA). Self-completed questionnaires were used to collect demographic and practice characteristics and perceptions about TJA. Confidence in referring appropriate patients for TJA was measured on a scale from 1 to 10; respondents scoring in the lowest tertile were considered to have 'low confidence'. Descriptive analyses were conducted and multiple logistic regression was used to determine key predictors of low confidence. RESULTS: 212 PCPs participated (58% response rate) (65% aged 50+ years, 45% female, 77% >15 years of practice). Perceptions about TJA were highly variable but on average, PCPs perceived that a typical surgical candidate would have moderate pain and disability, identified few absolute contraindications to TJA, and overestimated both the effectiveness and risks of TJA. On average, PCPs indicated moderate confidence in deciding who to refer. Independent predictors of low confidence were female physicians (OR = 2.18, 95% confidence interval (CI): 1.06-4.46) and reporting a 'lack of clarity about surgical indications' (OR = 3.54, 95% CI: 1.87-6.66). CONCLUSIONS: Variability in perceptions and lack of clarity about surgical indications underscore the need for decision support tools to inform PCP - patient decision making regarding referral for TJA.

Return to work and workplace activity limitations following total hip or knee replacement.

OBJECTIVE: Total hip (THR) and knee (TKR) replacements increasingly are performed on younger people making return to work a salient outcome. This research evaluates characteristics of individuals with early and later return to work following THR and TKR. Additionally, at work limitations pre-surgery and upon returning to work, and factors associated with work limitations were evaluated. METHODS: 190 THR and 170 TKR of a total 931 cohort participants were eligible (i.e., working or on short-term disability pre-surgery). They completed questionnaires pre-surgery and 1, 3, 6 and 12 months post-surgery that included demographics, type of occupation, and the Workplace Activity Limitations Scale (WALS). RESULTS: 166 (87%) and 144 (85%) returned to work by 12 months following THR and TKR, respectively. Early (1 month) return to work was associated with, male gender, university education, working in business, finance or administration, and low physical demand work. People with THR returned to work earlier than those with TKR. For both groups, less pain and every day functional limitations were associated with less workplace activity limitations at the time return to work. CONCLUSIONS: The majority of individuals working prior to surgery return to work following hip or knee replacement for osteoarthritis (OA) and experience fewer limitations at work than pre-surgery. The changing workforce dynamics and trends toward surgery at younger ages mean that these are important outcomes for clinicians to assess. Additionally, this is important information for employers in understanding continued participation in employment for people with OA.

Understanding recovery: changes in the relationships of the International Classification of Functioning (ICF) components over time.

The International Classification of Functioning, Disability and Health framework describes human functioning through body structure and function, activity and participation in the context of a person's social and physical environment. This work tested the temporal relationships of these components. Our hypotheses were: 1) there would be associations among physical impairment, activity limitations and participation restrictions within time; 2) prior status of a component would be associated with future status; 3) prior status of one component would influence status of a second component (e.g. prior activity limitations would be associated with current participation restrictions); and, 4) the magnitude of the within time relationships of the components would vary over time. Participants from Canada with primary hip or knee joint replacement (n = 931), an intervention with predictable improvement in pain and disability, completed standardized outcome measures pre-surgery and five times in the first year post-surgery. These included physical impairment (pain), activity limitations and participation restrictions. ICF component relationships were evaluated cross-sectionally and longitudinally using path analysis adjusting for age, sex, BMI, hip vs. knee, low back pain and mood. All component scores improved significantly over time. The path coefficients supported the hypotheses in that both within and across time, physical impairment was associated with activity limitation and activity limitation was associated with participation restriction; prior status and change in a component were associated with current status in another component; and, the magnitude of the path coefficients varied over time with stronger associations among components to three months post surgery than later in recovery with the exception of the association between impairment and participation restrictions which was of similar magnitude at all times. This work enhances understanding of the complexities of the ICF component relationships in evaluating disability over time. Further longitudinal studies including evaluation of contextual factors are required.

Self-management strategies in overweight and obese Canadians with arthritis.

OBJECTIVE: To estimate the prevalence of overweight and obese Canadians with arthritis and to describe their use of arthritis self-management strategies, as well as explore the factors associated with not engaging in any self-management strategies. METHODS: Respondents to the 2009 Survey on Living with Chronic Diseases in Canada, a nationally representative sample of 4,565 Canadians age ≥20 years reporting health professional-diagnosed arthritis (including more than 100 rheumatic diseases and conditions), were asked about the impact of their arthritis and how it was managed. Among the overweight (body mass index [BMI] 25-29.9 kg/m(2)) and obese (BMI ≥30 kg/m(2)) individuals with arthritis (n = 2,869), the use of arthritis self-management strategies (i.e., exercise, weight control/loss, classes, and community-based programs) were analyzed. Log binomial regression analyses were used to examine factors associated with engaging in none versus any (≥1) of the 4 strategies. RESULTS: More than one-quarter (27.4%) of Canadians with arthritis were obese and an additional 39.9% were overweight. The overweight and obese individuals with arthritis were mostly female (59.5%), age ≥45 years (89.7%), and reported postsecondary education (69.0%). While most reported engagement in at least 1 self-management strategy (84.9%), less than half (45.6%) engaged in both weight control/loss and exercise. Factors independently associated with not engaging in any self-management strategies included lower education, not taking medications for arthritis, and no clinical recommendations from a health professional. CONCLUSION: Fewer than half of the overweight and obese Canadians with arthritis engaged in both weight control/loss and exercise. The provision of targeted clinical recommendations (particularly low in individuals that did not engage in any self-management strategies) may help to facilitate participation.

The trajectory of recovery and the inter-relationships of symptoms, activity and participation in the first year following total hip and knee replacement.

OBJECTIVE: Primary total hip (THR) and knee (TKR) replacement outcomes typically include pain and function with a single time of follow-up post-surgery. This research evaluated the trajectory of recovery and inter-relationships within and across time of physical impairments (PI) (e.g., symptoms), activity limitations (AL), and social participation restrictions (PR) in the year following THR and TKR for osteoarthritis. DESIGN: Participants (hip: n=437; knee: 494) completed measures pre-surgery and at 2 weeks, 1, 3, 6 and 12 months post-surgery. These included PI (Hip Disability and Osteoarthritis Outcome Score (HOOS)/Knee Injury and Osteoarthritis Outcome Score (KOOS) symptoms and Chronic Pain Grade); AL (HOOS/KOOS activities of daily living and sports/leisure activities); and, PR (Late Life Disability and the Calderdale community mobility). Repeated measures analysis of variance (RANOVA) was used to evaluate the trajectory of recovery of outcomes and the inter-relationships of PI, AL and PR were evaluated using path analysis. All analyses were adjusted for age, sex, obesity, THR/TKR, low back pain and mood. RESULTS: THR: age 31-86 years with 55% female; TKR: age 35-88 years with 65% female. Significant improvements in outcomes were observed over time. However, improvements were lagged over time with earlier improvements in PI and AL and later improvements in PR. Within and across time, PI was associated with AL and AL was associated with PR. The magnitude of these inter-relationships varied over time. CONCLUSION: Given the lagged inter-relationship of PI, AL and PR, the provision and timing of interventions targeting all constructs are critical to maximizing outcome. Current care pathways focusing on short-term follow-up with limited attention to social and community participation should be re-evaluated.

Surveillance of systemic autoimmune rheumatic diseases using administrative data.

There is growing interest in developing tools and methods for the surveillance of chronic rheumatic diseases, using existing resources such as administrative health databases. To illustrate how this might work, we used population-based administrative data to estimate and compare the prevalence of systemic autoimmune rheumatic diseases (SARDs) across three Canadian provinces, assessing for regional differences and the effects of demographic factors. Cases of SARDs (systemic lupus erythematosus, scleroderma, primary Sjogren's, polymyositis/dermatomyositis) were ascertained from provincial physician billing and hospitalization data. We combined information from three case definitions, using hierarchical Bayesian latent class regression models that account for the imperfect nature of each case definition. Using methods that account for the imperfect nature of both billing and hospitalization databases, we estimated the over-all prevalence of SARDs to be approximately 2-3 cases per 1,000 residents. Stratified prevalence estimates suggested similar demographic trends across provinces (i.e. greater prevalence in females-versus-males, and in persons of older age). The prevalence in older females approached or exceeded 1 in 100, which may reflect the high burden of primary Sjogren's syndrome in this group. Adjusting for demographics, there was a greater prevalence in urban-versus-rural settings. In our work, prevalence estimates had good face validity and provided useful information about potential regional and demographic variations. Our results suggest that surveillance of some rheumatic diseases using administrative data may indeed be feasible. Our work highlights the usefulness of using multiple data sources, adjusting for the error in each.

Development of a population-based microsimulation model of osteoarthritis in Canada.

OBJECTIVES: The purpose of the study was to develop a population-based simulation model of osteoarthritis (OA) in Canada that can be used to quantify the future health and economic burden of OA under a range of scenarios for changes in the OA risk factors and treatments. In this article we describe the overall structure of the model, sources of data, derivation of key input parameters for the epidemiological component of the model, and preliminary validation studies. DESIGN: We used the Population Health Model (POHEM) platform to develop a stochastic continuous-time microsimulation model of physician-diagnosed OA. Incidence rates were calibrated to agree with administrative data for the province of British Columbia, Canada. The effect of obesity on OA incidence and the impact of OA on health-related quality of life (HRQL) were modeled using Canadian national surveys. RESULTS: Incidence rates of OA in the model increase approximately linearly with age in both sexes between the ages of 50 and 80 and plateau in the very old. In those aged 50+, the rates are substantially higher in women. At baseline, the prevalence of OA is 11.5%, 13.6% in women and 9.3% in men. The OA hazard ratios for obesity are 2.0 in women and 1.7 in men. The effect of OA diagnosis on HRQL, as measured by the Health Utilities Index Mark 3 (HUI3), is to reduce it by 0.10 in women and 0.14 in men. CONCLUSIONS: We describe the development of the first population-based microsimulation model of OA. Strengths of this model include the use of large population databases to derive the key parameters and the application of modern microsimulation technology. Limitations of the model reflect the limitations of administrative and survey data and gaps in the epidemiological and HRQL literature.

Assessing damage in individual joints in rheumatoid arthritis: a new method based on the Larsen system.

OBJECTIVES: To evaluate observer agreement using the Larsen system (LS) and a Modified Larsen system (ML) when assessing individual joints of the hands and wrists in rheumatoid arthritis, and to compare the two systems. To determine the minimally important difference (MID) for the ML. METHODS: Thirty radiographs of hands and wrists from 10 patients who presented with RA were graded by two blinded observers, using the LS and then the ML. Patients were followed for a mean of 7.2 years (range: 4-10 years). Inter- and intra-observer agreement were calculated using the kappa statistic with linear incremental weights. Inter-observer agreement was also computed for the summed score, using an intraclass correlation coefficient. Inter-observer error was estimated by calculating the mean and standard deviation of the grading differences between the two observers. Prevalence of damage was calculated as a ratio of damage: no damage and expressed as a percentage. Pairs of radiographs were comparatively graded using a seven-point Likert scale. RESULTS: The kappa statistic for inter-observer agreement was 0.38 (marginal reproducibility) for the LS and 0.52 (good reproducibility) for the ML (P = 0.004). Using a difference of one grade as perfect agreement, it was 0.56 (good reproducibility) for the LS and 0.87 (excellent reproducibility) for the ML (P = 0.001). Intra-observer agreement was high in both systems. The distribution of ML-grade differences varied according to the level of the Likert scale: for "a little bit worse", representing the smallest amount of detectable damage progression, the distribution differences peaked around two grades. This value represented a MID 87% of the time. CONCLUSIONS: The LS lacks precision for individual joints. The ML, it is proposed, has more detailed definitions of grades, and is more reliable. When pairs of radiographs were compared, a two-grade difference on the ML was the MID.

Rasch analysis of the Western Ontario McMaster (WOMAC) Osteoarthritis Index: results from community and arthroplasty samples.

BACKGROUND AND OBJECTIVE: This study is based on secondary analysis of Western Ontario McMaster Osteoarthritis Index (WOMAC) data from a community sample over 55 years and total hip or knee arthroplasty samples presurgery and 1-year postoperative. METHODS: The WOMAC data were evaluated by Rasch analysis. Data were considered to fit the Rasch mathematical model for the pain and physical dimensions of the WOMAC if unidimensionality was confirmed by principle component analysis of the subscale and the residuals from the Rasch analysis, infit and outfit statistics were in the range of 0.80 to 1.20; if there was no differential item functioning based on gender or hip vs. knee subjects; and, if there was stability of the item logits across the three data samples. RESULTS: A three-item pain dimension (excluding night pain and pain on standing) and a 14-item physical dimension (excluding heavy domestic duties, getting in and out of the bath and getting on and off the toilet) fit the Rasch model based on these criteria. CONCLUSION: In evaluating existing health status questionnaires using Rasch methodology, it is important to evaluate relevant patient samples and longitudinal data when the measure is intended to evaluate change in status. By these criteria, a modified WOMAC questionnaire fits the Rasch model and has interval-level scaling properties.

Insomnia and health problems in Canadians.

STUDY OBJECTIVES: The objective of this study was to determine the prevalence of, and to identify the relative contribution of selected factors associated with insomnia in the Canadian population age 15 and older. DESIGN: Weighted analysis of cross-sectional data from the Canadian General Social Survey, Cycle 6, 1991. Prevalence estimates were calculated for the total and age-specific Canadian population age 15 and older. Multiple logistic regression techniques were employed to study the contribution of an array of sociodemographic, lifestyle, stress, and physical health factors to the experience of insomnia. SETTING: N/A. PARTICIPANTS: A representative sample of the Canadian household population age 15+ (n=11,924). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Twenty-four percent of the Canadian population age 15+ report insomnia. The following factors were associated with insomnia in multivariate logistic regression: female gender, being widowed or single, low education, low income, not being in the labor force, ever having smoked, life stress, specific chronic physical health problems (circulatory, digestive and respiratory disease, migraine, allergy and rheumatic disorders), pain, activity limitation and health dissatisfaction. Age was not significantly associated with insomnia. CONCLUSIONS: Insomnia was highly prevalent among the non-institutionalized Canadian population age 15 and older. A very stressful life, severe pain and dissatisfaction with one's health demonstrated the highest odds ratios associated with insomnia. Increasing age per se and lifestyle factors were not significantly associated with insomnia.

Arthritis and rheumatism are neglected health priorities: a bibliometric study.

OBJECTIVE: To investigate the frequency of publications about arthritis and rheumatic diseases relative to other diseases and to examine which topics received most attention. METHODS: Available health statistics were used to quantify the burden of illness due to musculoskeletal (MSK) conditions. Next, a bibliographic analysis of MEDLINE was performed comparing disease categories using the MeSH tree structure for 1991 and 1996. Diseases were ranked according to the frequency of citations attributable to them and further analyses were performed for journal categories, MeSH subheadings, and the frequency of citations for specific types of arthritis and rheumatic diseases. RESULTS: Compared with 9 other causes, MSK diseases are leading contributors to health professional consultations, total health costs, chronic ill health, and disability. In contrast, MSK diseases ranked ninth among twelve major MEDLINE disease categories in 1996 and 1991. These rankings were similarly low across journal categories reflecting basic science research and clinical application. Radiography, rehabilitation, history and embryology were the most frequently used subheadings for MSK diseases. In 1996, there were 16,603 citations for MSK diseases, led by bone diseases (7,304 citations), joint diseases (4,987), muscular diseases (4,236), arthritis (3,555), and rheumatic diseases (3195). Among arthritic and rheumatic diseases, rheumatoid arthritis had the largest number of citations (2,004), followed by systemic lupus erythematosus (927) and osteoarthritis (793). CONCLUSION: Arthritis and rheumatic diseases receive far less attention in the scientific literature than is warranted by their enormous and growing disease burden. Both research and dissemination are lacking and more adequate resources for these activities are indicated.

The contribution of arthritis and arthritis disability to nonparticipation in the labor force: a Canadian example.

OBJECTIVE: To examine the factors affecting labor force participation and understand how arthritis affects labor force participation in a Canadian working population. METHODS: Data from the 1990 Ontario Health Survey population (n = 35,221) were used. Labor force participation was dichotomized as in the labor force and not in the labor force. Stratified logistic regression analyses by sex were carried out to identify factors associated with not being in the labor force, including arthritis, chronic disorders, and sociodemographic and family composition variables. RESULTS: Overall, 6.7% of men and 23.0% of women were not in the labor force compared with 18.6% and 36.0%, respectively, of men and women with arthritis. After controlling for other covariates, disability caused by arthritis was significantly associated with increased risk of being out of the labor force, with odds ratios of 2.70 for men and 1.91 for women. Low education, pain, and nonarthritis disability were also significantly associated with being out of the labor force. The effects of age and family structure on employment were sex dependent. Women were at higher risk at all age groups. Men with dependent children were more likely to work, as were women who lived alone. For women, having dependent children increased the likelihood of not being in the labor force. CONCLUSION: People with arthritis disability were more likely to be out of the labor force. It was not arthritis per se that limited people in labor force participation, but rather the arthritis disabilities.

Determining the need for hip and knee arthroplasty: the role of clinical severity and patients' preferences.

BACKGROUND: Area variation in the use of surgical interventions such as arthroplasty is viewed as concerning and inappropriate. OBJECTIVES: To determine whether area arthroplasty rates reflect patient-related demand factors, we estimated the need for and the willingness to undergo arthroplasty in a high- and a low-use area of Ontario, Canada. RESEARCH DESIGN: Population-based mail and telephone survey. SUBJECTS: All adults aged > or =55 years in a high (n = 21,925) and low (n = 26,293) arthroplasty use area. MEASURES: We determined arthritis severity and comorbidity with questionnaires, established the presence of arthritis with examination and radiographs, and evaluated willingness to have arthroplasty with interviews. Potential arthroplasty need was defined as severe arthritis, no absolute contraindication for surgery, and evidence of arthritis on examination and radiographs. Estimates of need were then adjusted for patients' willingness to undergo arthroplasty. RESULTS: Response rates were 72.0% for questionnaires and interviews. The potential need for arthroplasty was 36.3/1,000 respondents in the high-rate area compared with 28.5/1,000 in the low-rate area (P <0.0001). Among individuals with potential need, only 14.9% in the high-rate area and 8.5% in the low-rate area were definitely willing to undergo arthroplasty (P = 0.03), yielding adjusted estimates of need of 5.4/1,000 and 2.4/1,000 in the high- and low-rate areas, respectively. CONCLUSIONS: Demonstrable need and willingness were greater in the high-rate area, suggesting these factors explain in part the observed geographic rate variations for this procedure. Among those with severe arthritis, no more than 15% were definitely willing to undergo arthroplasty, emphasizing the importance of considering both patients' preferences and surgical indications when evaluating need and appropriateness of rates for surgery.

Improvements following short term home based physical therapy are maintained at one year in people with moderate to severe rheumatoid arthritis.

OBJECTIVE: We previously demonstrated the efficacy of a 6 week home based physical therapy (PT) intervention for people with moderate to severe rheumatoid arthritis (RA). This followup study determined if short term improvements were maintained to one year. METHODS: Participants in the short term study were randomly assigned to receive a PT intervention (education, exercise, and pain relief modalities) delivered by physiotherapists with advanced rheumatology training (Weeks 0 to 6) or to a wait list control group. The control group received the intervention between Weeks 6 to 12. Outcome measures included the Stanford Arthritis Self-Efficacy Scale (SES), the Arthritis Community Research and Evaluation Unit Rheumatoid Arthritis Knowledge Questionnaire (KQ), and a visual analog scale for pain. Disease activity measures (tender joints, grip strength, and morning stiffness) were also included. MANOVA was used to compare within-subject scores at baseline and at 12 and 52 weeks. Paired t tests were used to determine if 12 week changes were maintained at 52 weeks. RESULTS: Of the 127 protocol completers, 117 (92.1%) were available for the one year followup. For those measures that showed significant improvement in the randomized controlled trial (SES, KQ, morning stiffness), improvements at 12 weeks were maintained at 52 weeks (p > 0.010). CONCLUSION: Subjects who participated in a short term home based PT intervention delivered by specially trained therapists reported improved outcomes following treatment, and these improvements were maintained at one year followup. Future studies need to explore the relative contributions of education, exercise, home based care, therapist training, and reinforcement strategies in improving longterm outcomes in RA.

Adaptation to chronic illness and disability and its relationship to perceptions of independence and dependence.

This study extends research on living with chronic physical illness and disability by examining how adaptation processes are associated with different activity domains and how the combination of adaptations and activity domains relate to older adults' perceptions of their independence and dependence, helplessness, emotional reactivity, and coping efficacy. The study investigated the behavioral efforts that 286 older adults with osteoarthritis and/or osteoporosis used to adapt to disability arising from their condition. The findings revealed that adults used a wide range of adaptations, including compensations for loss, optimizing performance, limiting or restricting activities, and gaining help from others. The relative use of each of these adaptations varied across 5 domains of activity: personal care, in-home mobility, community mobility, household activities, and valued activities. Moreover, older adults' perceptions of their independence, dependence, helplessness, emotional reactivity, and coping efficacy varied depending on the domain of activity examined and the type of adaptation used.

The nature of increased hospital use in poor neighbourhoods: findings from a Canadian inner city.

The relationship between socioeconomic factors and hospital use is not well understood in the Canadian context. We used the 1991 Canada census and 1990-92 Ontario hospital discharge abstracts for residents of southeast Toronto to calculate crude and age-sex adjusted rates of hospital admission, bed days, and costs by quintile of low-income households. Population-based rates of admission to hospital, bed days and costs were all significantly related to census tract income (p < 0.01 for males and females). The number of admissions per person admitted was significantly associated with census tract income (p < 0.01 for males and females), but length of stay and resource intensity weight were not. Hospital costs were 50.0% higher for the poorest quintile of neighbourhoods than for the wealthiest and 35.8% higher than for the middle-income quintile. Poor urban neighbourhoods may require more resources than previously anticipated, related to higher hospital admission and readmission rates.

Arthritis prevalence and place of birth: findings from the 1994 Canadian National Population Health Survey.

This paper describes the prevalence of arthritis in Canadians by ethnic origin, including Asians, Europeans/Australians, and North American-born Canadians. Data for this study were derived from the 1994 Canadian National Population Health Survey, a cross-sectional survey with a sample of 39,240 persons aged 20 years and older. Arthritis was defined as a long-term health condition of "arthritis or rheumatism" diagnosed by a health professional. Place of birth was determined according to self-reported country of birth. Unconditional multiple logistic regression models were used to adjust for potential confounding effects. The crude prevalence of self-reported arthritis and rheumatism diagnosed by a health professional as a long-term condition for those aged 20 years and older in Canada was 14.2%. The age-sex adjusted prevalence by place of birth was 6.9% in Asians, 14.2% in Europeans/Australians, and 14.5% in North American-born Canadians. In the multivariate analyses using North America-born Canadians as baseline, the risk for arthritis (odds ratio = 0.56) was significantly lower in Asian-born Canadians after adjustment for age, sex, education, income, occupation, and body mass index.

Differences between men and women in the rate of use of hip and knee arthroplasty.

BACKGROUND: Previous studies suggest that, for some conditions, women receive fewer health care interventions than men. We estimated the potential need for arthroplasty and the willingness to undergo the procedure in both men and women and examined whether there were differences between the sexes. METHODS: All 48,218 persons 55 years of age or older in two areas of Ontario, Canada, were surveyed by mail and telephone to identify those with hip or knee problems. In these subjects, we assessed the severity of arthritis and the presence of coexisting conditions by questionnaire, documented arthritis by examination and radiography, and conducted interviews to evaluate the subjects' willingness to undergo arthroplasty. The potential need for arthroplasty was defined by the presence of severe symptoms and disability, the absence of any absolute contraindications to surgery, and clinical and radiographic evidence of arthritis. The estimates of need were then adjusted for the subjects' willingness to undergo arthroplasty. RESULTS: The overall response rates were at least 72 percent for the questionnaires and interviews. As compared with men, women had a higher prevalence of arthritis of the hip or knee (age-adjusted odds ratio, 1.76; P<0.001) and had worse symptoms and greater disability, but women were less likely to have undergone arthroplasty (adjusted odds ratio, 0.78; P<0.001). Despite their equal willingness to have the surgery, fewer women than men had discussed the possibility of arthroplasty with a physician (adjusted odds ratio, 0.63). The numbers of people with a potential need for hip or knee arthroplasty were 44.9 per 1000 among women and 20.8 per 1000 among men. After adjustment for willingness to undergo the procedure, the numbers were 5.3 per 1000 for women and 1.6 per 1000 for men. CONCLUSIONS: There is underuse of arthroplasty for severe arthritis in both sexes, but the degree of underuse is more than three times as great in women as in men.