Health-related quality of life in relation to symptomatic and radiographic definitions of knee osteoarthritis: data from Osteoarthritis Initiative (OAI) 4-year follow-up study.

BACKGROUND: The purpose was to quantify the decrement in health utility (referred as disutility) associated with knee osteoarthritis (OA) and different symptomatic and radiographic uni- and bilateral definitions of knee OA in a repeated measures design of persons with knee OA or at increased risk of developing knee OA. METHODS: Data were obtained from the Osteoarthritis Initiative database. SF-12 health-related quality of life was converted into SF-6D utilities, and were then handled as the health utility loss by subtracting 1.000 from the utility score, yielding a negative value (disutility). Symptomatic OA was defined by radiographic findings (Kellgren-Lawrence, K-L, grade ≥ 2) and frequent knee pain in the same knee. Radiographic OA was defined by five different definitions (K-L ≥ 2 unilaterally / bilaterally, or the highest / mean / combination of K-L grades of both knees). Repeated measures generalized estimating equation (GEE) models were used to investigate disutility in relation to these different definitions. RESULTS: Utility decreased with worsening of symptomatic or radiographic status of knee OA. The participants with bilateral and unilateral symptomatic knee OA had 0.03 (p < 0.001) and 0.02 (p < 0.001) points lower utility scores, respectively, compared with the reference group. The radiographic K-L grade 4 defined as the mean or the highest grade of both knees was related to a decrease of 0.04 (p < 0.001) and 0.03 (p < 0.001) points in utility scores, respectively, compared to the reference group. CONCLUSIONS: Knee OA is associated with diminished health-related quality of life. Health utility can be quantified in relation to both symptomatic and radiographic uni- and bilateral definitions of knee OA, and these definitions are associated with differing disutilities. The performance of symptomatic definition was better, indicating that pain experience is an important factor in knee OA related quality of life.

Evaluation of the Effect of Bariatric Surgery-Induced Weight Loss on Knee Gait and Cartilage Degeneration.

The objective of the study was to investigate the effects of bariatric surgery-induced weight loss on knee gait and cartilage degeneration in osteoarthritis (OA) by combining magnetic resonance imaging (MRI), gait analysis, finite element (FE) modeling, and cartilage degeneration algorithm. Gait analyses were performed for obese subjects before and one-year after the bariatric surgery. FE models were created before and after weight loss for those subjects who did not have severe tibio-femoral knee cartilage loss. Knee cartilage degenerations were predicted using an adaptive cartilage degeneration algorithm which is based on cumulative overloading of cartilage, leading to iteratively altered cartilage properties during OA. The average weight loss was 25.7±11.0 kg corresponding to a 9.2±3.9 kg/m2 decrease in body mass index (BMI). External knee rotation moment increased, and minimum knee flexion angle decreased significantly (p < 0.05) after weight loss. Moreover, weight loss decreased maximum cartilage degeneration by 5±23% and 13±11% on the medial and lateral tibial cartilage surfaces, respectively. Average degenerated volumes in the medial and lateral tibial cartilage decreased by 3±31% and 7±32%, respectively, after weight loss. However, increased degeneration levels could also be observed due to altered knee kinetics. The present results suggest that moderate weight loss changes knee kinetics and kinematics and can slow-down cartilage degeneration for certain patients. Simulation results also suggest that prediction of cartilage degeneration is subject-specific and highly depend on the altered gait loading, not just the patient's weight.

Effectiveness of a cognitive-behavioural group intervention for knee osteoarthritis pain: a randomized controlled trial.

OBJECTIVE: To assess the effectiveness of a six week cognitive-behavioural group intervention in patients with knee osteoarthritis pain. DESIGN: Single-blinded randomized controlled trial. STUDY SETTING: Primary care providers in a medium-sized city in Finland. PATIENTS: A total of 111 participants aged from 35 to 75 with clinical symptoms and radiographic grading (Kellgren-Lawrence 2-4) of knee osteoarthritis were included. INTERVENTIONS: In the intervention group, 55 participants attended a cognitive-behavioural training programme for pain management with six weekly group sessions supervised by a psychologist and a physiotherapist. Concurrently, they and the 56 participants of the control group continued in ordinary GP care that was not altered by the study. MAIN MEASURES: The primary outcome on three-month and 12-month follow-up was the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis index pain subscale. Secondary outcome measures included self-reports of pain and physical function, health-related quality of life, and a comprehensive set of psychological questionnaires. RESULTS: Mixed model results showed no significant differences between the intervention and control group for any measures of pain or function. A significant difference between the groups was found in the Pain Self-Efficacy Questionnaire (Pr = 0.022) in favour of the control group, and in the RAND-36 emotional well-being subscale in favour of the intervention group (Pr = 0.038). Conventional group comparisons of mean follow-up values showed no significant differences in any of the outcome variables. CONCLUSION: This trial could not confirm the hypothesized advantage of a cognitive-behavioural training programme over ordinary GP care in knee osteoarthritis pain patients. TRIAL REGISTRATION: Current Controlled Trials ISRCTN64794760.

Multiple psychological factors are associated with poorer functioning in a sample of community-dwelling knee osteoarthritis patients.

BACKGROUND: Knee osteoarthritis (OA) is the most common type of arthritis and imposes a heavy burden on individual welfare among elderly people. There is preliminary evidence that psychological factors play a role in functional ability and pain in knee OA patients, particularly with respect to the surgery outcome. Less is known about psychological factors among community-dwelling patients with knee OA. OBJECTIVES: We aimed to determine which psychological factors are associated with pain and functional ability among community-dwelling knee OA patients using a comprehensive set of psychological questionnaires. METHODS: In the cross-sectional baseline setting of a prospective, randomized controlled intervention study, 111 patients aged from 35 to 75 years with clinical symptoms and radiographic grading of knee OA were included. They completed a comprehensive set of psychological questionnaires, including measures of resources and coping, fear and catastrophizing, and distress. RESULTS: In cross-sectional comparisons, pain self-efficacy, fear of movement, pain catastrophizing, and elevated anxiety were associated with pain and a poorer functional ability. In logistic regression analysis, independent association was seen between pain self-efficacy and poorer functioning. Knee OA patients also reported elevated levels of anxiety. CONCLUSIONS: The results reveal that both pain self-efficacy and negatively charged emotion and expectations toward pain are important factors when dealing with knee OA patients. Failure to consider these will probably contribute to prolonged disability and further pain. The results call for the routine assessment of multiple psychological factors in knee OA.

Sex-related differential item functioning of the Jenkins Sleep Scale: a cross-sectional study among 77 967 employees in the Finnish public sector.

OBJECTIVES: To investigate if the Jenkins Sleep Scale (JSS) demonstrates sex-related differential item functioning (DIF). DESIGN: Cross-sectional study. SETTING: Survey data from the Finnish Public Sector study (2015-2017). PARTICIPANTS: 77 967 employees in the Finnish public sector, with a mean age of 51.9 (SD 13.1) years and 82% women. OUTCOME MEASURES: Item response theory estimates: difficulty and discrimination parameters of the JSS and differences in these parameters between men and women. RESULTS: The mean JSS total score was 6.4 (4.8) points. For all four items of the JSS, the difficulty parameter demonstrated a slight shift towards underestimation of the severity of sleep difficulties. The discrimination ability of all four items was moderate to high. For the JSS composite score, overall discrimination ability was moderate (0.98, 95% CI 0.97 to 0.99). Mild uniform DIF (p<0.001) was seen: two items showed better discrimination ability among men and two others among women. CONCLUSIONS: The JSS showed overall good psychometric properties among this healthy population of employees in the Finnish public sector. The JSS was able to discriminate people with different severities of sleep disturbances. However, when using the JSS, the respondents might slightly underestimate the severity of these disturbances. While the JSS may produce slightly different results when answered by men and women, these sex-related differences are probably negligible when applied to clinical situations.

Determinants of pain and functioning in hip osteoarthritis - a two-year prospective study.

OBJECTIVE: To identify predictors of pain and disability in hip osteoarthritis. DESIGN: A prospective analysis of determinants of pain and functioning in hip osteoarthritis. STUDY SETTING: Rehabilitation clinic in a central hospital. PATIENTS: A total of 118 men and women aged 55-80 years who had radiologically diagnosed hip osteoarthritis and associated clinical symptoms and participated in a randomized controlled trial. MAIN MEASURES: The self-reported disease-specific pain and physical function were assessed using the pain and functioning subscales of the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis index. The self-reported generic physical and mental functioning were assessed by using the Finnish-validated SF-36-item Health Survey RAND-36 subscales for function and physical and mental component summary scores. Outcome measures were recorded at 0, 3, 6, 12, 18 and 24 months. RESULTS: Multivariate linear mixed model analyses revealed that lower disease-specific pain score and better functioning (WOMAC) were predicted by higher educational level (9.61 (3.15 to 16.07); 9.07 (2.05 to 16.09)), supervised exercise training (-10.13 (-17.87 to -2.39); -11.58 (-19.40 to -3.77)), habitual conditioning physical activity (-0.48 (-0.96 to -0.01); -0.39 (-0.84 to 0.05)), absence of comorbidities (-6.30 (-12.35 to -0.24); -7.87 (-14.45 to -1.30)) and absence of additional knee osteoarthritis (-7.62 (-13.87 to -1.36); -8.02 (-14.81 to -1.23)), respectively. The same factors, except for the comorbidities, also predicted general physical functioning score (RAND-36). CONCLUSIONS: Higher education, absence of knee osteoarthritis and comorbidities, supervised exercise training and habitual conditioning physical activity predicted a lower presence of pain and better functional status in patients with hip osteoarthritis.

Effectiveness of a cognitive-behavioral group intervention for knee osteoarthritis pain: protocol of a randomized controlled trial.

BACKGROUND: Knee osteoarthritis is the most common type of arthritis, with pain being its most common symptom. Little is known about the psychological aspects of knee osteoarthritis pain. There is an emerging consensus among osteoarthritis specialists about the importance of addressing not only biological but also psychosocial factors in the assessment and treatment of osteoarthritis. As few studies have evaluated the effect of psychological interventions on knee osteoarthritis pain, good quality randomized controlled trials are needed to determine their effectiveness. METHODS/DESIGN: We intend to conduct a 6-week single-blinded randomized controlled trial with a 12-month follow-up. Altogether, 108 patients aged from 35 to 75 years with clinical symptoms and radiographic grading (KL 2-4) of knee osteoarthritis will be included. The clinical inclusion criteria are pain within the last year in or around the knee occurring on most days for at least one month, and knee pain of ≥ 40 mm on a 100-mm visual analogue scale in the WOMAC pain subscale for one week prior to study entry. Patients with any severe psychiatric disorder, other back or lower limb pain symptoms more aggravating than knee pain, or previous or planned lower extremity joint surgery will be excluded. The patients will be randomly assigned to a combined GP care and cognitive-behavioral intervention group (n = 54) or to a GP care control group (n = 54). The cognitive-behavioral intervention will consist of 6 weekly group sessions supervised by a psychologist and a physiotherapist experienced in the treatment of pain. The main goals of the intervention are to reduce maladaptive pain coping and to increase the self-management of pain and disability. The follow-up-points will be arranged at 3 and 12 months. The primary outcome measure will be the WOMAC pain subscale. Secondary outcome measures will include self-reports of pain and physical function, a health related quality of life questionnaire, and various psychological questionnaires. Personnel responsible of the data analysis will be blinded. DISCUSSION: This study addresses the current topic of non-pharmacological conservative treatment of knee OA-related pain. We anticipate that these results will provide important new insights to the current care recommendations. TRIAL REGISTRATION: Current Controlled Trials ISRCTN64794760.

Toward Tailored Rehabilitation by Implementation of a Novel Musculoskeletal Finite Element Analysis Pipeline.

Tissue-level mechanics (e.g., stress and strain) are important factors governing tissue remodeling and development of knee osteoarthritis (KOA), and hence, the success of physical rehabilitation. To date, no clinically feasible analysis toolbox has been introduced and used to inform clinical decision making with subject-specific in-depth joint mechanics of different activities. Herein, we utilized a rapid state-of-the-art electromyography-assisted musculoskeletal finite element analysis toolbox with fibril-reinforced poro(visco)elastic cartilages and menisci to investigate knee mechanics in different activities. Tissue mechanical responses, believed to govern collagen damage, cell death, and fixed charge density loss of proteoglycans, were characterized within 15 patients with KOA while various daily activities and rehabilitation exercises were performed. Results showed more inter-participant variation in joint mechanics during rehabilitation exercises compared to daily activities. Accordingly, the devised workflow may be used for designing subject-specific rehabilitation protocols. Further, results showed the potential to tailor rehabilitation exercises, or assess capacity for daily activity modifications, to optimally load knee tissue, especially when mechanically-induced cartilage degeneration and adaptation are of interest.

Minor influence of lifelong voluntary exercise on composition, structure, and incidence of osteoarthritis in tibial articular cartilage of mice compared with major effects caused by growth, maturation, and aging.

We investigated the effects of lifelong voluntary exercise on articular cartilage of mice. At the age of 4 weeks C57BL mice (n = 152) were divided into two groups, with one group serving as a sedentary control whereas the other was allowed free access to a running wheel from the age of 1 month onward. Mice were euthanized at four different time points (1, 2, 6, and 18 months of age). Articular cartilage samples were gathered from the load-bearing area of the tibial medial plateaus, and osteoarthritis was graded. Additionally, the proteoglycan content distribution was assessed using digital densitometry, collagen fibril orientation, and parallelism with polarized light microscopy, and collagen content using Fourier transform infrared imaging spectroscopy. The incidence of osteoarthritis increased with aging, but exercise had no effect on this trend. Furthermore, the structure and composition revealed significant growth, maturation, and age-dependent properties. Exercise exerted a minor effect on collagen fibril orientation in the superficial zone. Fibril orientation at 2 months of age was more perpendicular to surface (p < 0.05) in controls compared with runners, whereas the situation was reversed at the age of 18 months (p < 0.05). The collagen content of the superficial zone was higher (p < 0.01) at the age of 18 months in controls compared with runners but the proteoglycan content did not display any exercise-dependent changes. In conclusion, growth, maturation, and aging exerted a clear effect on integrity, structure, and composition of medial tibial plateau articular cartilage in mice, whereas lifelong voluntary exercise had only a minor effect on collagen architecture and content.

A pragmatic randomized controlled study of the effectiveness and cost consequences of exercise therapy in hip osteoarthritis.

OBJECTIVE: To evaluate the short- and long-term effectiveness of exercise training in relation to pain, function and direct costs to health care systems attributable to hip osteoarthritis. DESIGN: Prospective, two-year randomized controlled trial. SETTING: An outpatient primary health care setting. SUBJECTS: One hundred and twenty men and women aged from 55 to 80, with radiologically diagnosed hip osteoarthritis with associated clinical symptoms. INTERVENTIONS: The combined exercise and general practitioner (GP) care group received 12 supervised (once per week) exercise sessions at the baseline and four additional booster sessions one year later. Both groups received standard GP care. MAIN MEASURES: The WOMAC Osteoarthritis Index, physical functioning score of RAND-36 (SF-36), the use and health care system costs of doctor visits and physiotherapy associated with hip osteoarthritis, number of total hip replacements, the use of analgesic and non-steroidal anti-inflammatory drugs (NSAIDs), performance-based outcome scores and body mass index (BMI). RESULTS: There were no differences between the groups with respect to WOMAC hip pain, physical functioning score of RAND-36, performance-based outcome scores or BMI. The effect of the exercise intervention on WOMAC function was statistically significant at 6 months (mean = -7.5; 95% confidence interval (CI) -13.9 to -1.0; P = 0.02) and 18 months (mean = -7.9; 95% CI -15.3 to -0.4; P = 0.04). There were no statistically significant differences in the total health care system costs between the groups. CONCLUSION: The mostly home-based exercise training programme provided in this study did not result in reduced hip pain over the two-year follow-up period.

Sample size for prospective studies of hip joint space width narrowing in osteoarthritis by the use of radiographs.

OBJECTIVE: To determine the number of participants required in controlled clinical trials investigating the progression of osteoarthritis (OA) of the hip as evaluated by the joint space width (JSW) on radiographs and to evaluate the reproducibility of the JSW measurement methods. MATERIALS AND METHODS: Anteroposterior radiographs of hip were taken from 13 healthy volunteers and from 18 subjects with radiographic hip OA. The reproducibility of the JSW was determined from four segments using digital caliper measurements performed on film radiographs and using semiautomatic computerized image analysis of digitized images. Pearson correlation coefficient, coefficient of variability [CV (%)], and sample size values were calculated. RESULTS: It was found that 20 was a typical number of patients for a sufficiently powered study. The highest sample size was found in subjects with OA in the lateral segment. The reproducibility of the semiautomatic computerized method was not significantly better than the digital caliper method. CONCLUSION: The number of study subjects required to detect a significant joint space narrowing in follow-up studies is influenced by the baseline hip joint OA severity. The JSW measurements with computerized image analysis did not improve the reproducibility and thus performing JSW measurements with a digital caliper is acceptable.

Associations of Metabolic Syndrome and Its Components with the Risk of Incident Knee Osteoarthritis Leading to Hospitalization: A 32-Year Follow-up Study.

OBJECTIVES: To examine whether metabolic syndrome or its individual components predict the risk of incident knee osteoarthritis (OA) in a prospective cohort study during a 32-year follow-up period. DESIGN: The cohort consisted of 6274 participants of the Mini-Finland Health Survey, who were free from knee OA and insulin-treated diabetes at baseline. Information on the baseline characteristics, including metabolic syndrome components, hypertension, elevated fasting glucose, elevated triglycerides, reduced high-density lipoprotein, and central obesity were collected during a health examination. We drew information on the incidence of clinical knee OA from the national Care Register for Health Care. Of the participants, 459 developed incident knee OA. In our full model, age, gender, body mass index, history of physical workload, smoking history, knee complaint, and previous injury of the knee were entered as potential confounding factors. RESULTS: Having metabolic syndrome at baseline was not associated with an increased risk of incident knee OA. In the full model, the hazard ratio for incident knee OA for those with metabolic syndrome was 0.76 (95% confidence interval [0.56, 1.01]). The number of metabolic syndrome components or any individual component did not predict an increased risk of knee OA. Of the components, elevated plasma fasting glucose was associated with a reduced risk of incident knee OA (hazard ratio 0.71, 95% confidence interval [0.55, 0.91]). CONCLUSIONS: Our findings do not support the hypothesis that metabolic syndrome or its components increase the risk of incident knee OA. In fact, elevated fasting glucose levels seemed to predict a reduced risk.

Obesity, physically demanding work and traumatic knee injury are major risk factors for knee osteoarthritis--a population-based study with a follow-up of 22 years.

OBJECTIVE: Several studies have shown that knee OA is associated with obesity, physical stress at work, traumatic knee injuries, heredity and female gender. However, the body of such evidence comes from cross-sectional or case-control studies, and from only a few follow-up studies, mostly of short duration. Based on the nationwide Mini-Finland Health Survey, we analysed the potential risk factors for prediction of incident knee OA in the long term. METHODS: Focused on major health problems, the survey was carried out in 1978-80 in a sample of 8000 subjects, representative of the Finnish population aged > or =30 years. Altogether 823 subjects free from knee OA at the baseline were re-examined in 2000-01, and after the intervening 22 years 94 new cases of knee OA were found. Knee OA was diagnosed on both occasions by physicians using information on disease histories, symptoms and standardized clinical examinations. RESULTS: The risk of developing knee OA was strongly associated with BMI (kg/m(2)); adjusted for age and gender and other covariates, and compared with the reference category (BMI < 25.0); the relative odds ratios (ORs) with 95% CIs were 1.7 (95% CI 1.0, 2.8) and 7.0 (95% CI 3.5, 14.10) for subjects with BMIs 25.0-29.9 and > or =30.0, respectively. Similarly, the adjusted OR for the heaviest category of physical stress at work was 18.3 (95% CI 4.2, 79.4) compared with the lightest category, and 5.1 (95% CI 1.4, 19.0) for permanent complaints due to past knee injury. CONCLUSIONS: This prospective study confirms the roles of obesity, heavy work load and knee injury in the aetiology of knee OA.

Multidisciplinary rehabilitation after primary total knee arthroplasty: a randomized controlled study of its effects on functional capacity and quality of life.

OBJECTIVE: To examine whether a multidisciplinary rehabilitation programme can improve functional recovery and quality of life and reduce the use of rehabilitation services compared with conventional care one year after total knee arthroplasty. DESIGN: Prospective, randomized, non-blinded, controlled trial. SETTING: An outpatient centre-based setting. SUBJECTS: Eighty-six patients who were scheduled for primary total knee arthroplasty due to osteoarthritis of the knee. INTERVENTIONS: A ten-day multidisciplinary rehabilitation programme, which was focused on enhancing functional capacity, was organized 2-4 months after surgery. In both groups, a standard amount of physiotherapy was included in conventional care. MAIN MEASURES: The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the 15D, 15-m walk test, stair test, isometric strength measurement of the knee. Use of rehabilitation services was asked about with a questionnaire. Outcomes were assessed preoperatively and at 2-, 6- and 12-month follow-ups. RESULTS: In both groups, functional capacity and quality of life improved significantly. The mean absolute change in the WOMAC function score was -32.4 mm (SD 26.4) in the rehabilitation group and -32.8 mm (SD 20.1) in the control group (P-time*group = 0.40). No difference was found between groups in any outcome measure or in the use of rehabilitation services during the study period. CONCLUSIONS: This study indicates that for knee osteoarthritis patients treated with primary total knee arthroplasty, a 10-day multidisciplinary outpatient rehabilitation programme 2-4 months after surgery does not yield faster attainment of functional recovery or improvement in quality of life than can be achieved with conventional care.

[Myofascial pain syndrome--fascial muscle pain]. / Myofaskiaalinen kipuoireyhtymä--lihasjuostekipu.

Symptoms of myofascial pain syndrome, i.e. fascial muscle pain may occur in several areas of the body, particularly in the neck-shoulder region. The muscle pain symptom in the neck-shoulder region is commonly termed tension neck pain or nonspecific neck pain, but myofascial pain syndrome can also be distinguished into its own diagnosis. This review deals with the clinical picture of myofascial pain syndrome along with pathophysiological hypotheses and treatment options.

Physical exercise improves properties of bone and its collagen network in growing and maturing mice.

This study characterized bone structure, composition, and mechanical properties in growing male mice. The development of the collagen network during maturation was monitored, and the effect of voluntary physical exercise was investigated. We hypothesized that increased bone loading from exercise would increase the amount and improve the properties of the collagen network during growth and maturation. Half of the mice (total n = 168) had access to running wheels, while half were kept sedentary. Weight and running activity were recorded, and groups of mice were killed at 1, 2, 4, and 6 months of age. The collagen network was assessed by biochemical evaluation of collagen content and cross-links and by tensile testing of decalcified bone. Mineralized femur was analyzed with pQCT and three-point-bending and femoral neck-strength tests. After 6 months, the exercising mice had 10% lower body weight than the sedentary group. There was no difference in the amount of collagen or collagen cross-links, while tensile testing had higher breaking force and stiffness of the collagen network in runners after 4 months but not after 6 months. The bone mineral density and cross-sectional area were higher in the running group after 6 months. Runners also showed higher breaking force and stiffness of the diaphysis and the femoral neck at 2 and 6 months. The significant modulation of mechanical properties of the collagen network without any change in collagen content indicates that physical exercise improves properties of the collagen network in maturing bone. The improvement after exercise of the properties of mineralized bone appears to be more pronounced and long-lasting compared to the early improved properties of the collagen network.

Disability in end-stage knee osteoarthritis.

OBJECTIVE: To examine the attributes of disability in end-stage knee osteoarthritis (OA) by analyzing the relationships between self-reported disability and objectively measured physical function after controlling pain, personal characteristic factors, and pathophysiological factors. METHODS: The present study adopted a cross-sectional design. The subjects (n=88, aged 60-80 years) were scheduled for primary unilateral total knee arthroplasty (TKA) due to knee OA. Self-reported disability and pain were measured with the Western Ontario and McMaster Universities OA Index (WOMAC) and the RAND 36-item Health Survey 1.0 (RAND-36). Physical performance tests included a 15-m walk test and stair performance. Knee isometric muscle strength was measured. A clinical examination included analyses of comorbidity, body mass index (BMI), and a detailed knee examination: The flexion range of motion (ROM) was measured; the presence of varus/valgus malalignments and antero-posterior laxity was assessed. Radiographs were analyzed with the Kellgren-Lawrence grading scale. RESULTS: In the linear regression model the WOMAC pain score, antero-posterior laxity of the knee, age, and BMI accounted for 54.8% of the variance in the WOMAC function score. In the bivariate analyses the WOMAC function score had a positive correlation with the 15-m walk (r(s)=0.32, p=0.003), stairs up (r(s)=0.40, p=0.001), and stairs down (r(s)=0.38, p=0.001) tests, and a negative correlation with RPT extension (r(s)=-0.45, p < 0.001) and RPT flexion (r(s)=-0.39, p=0.001) of the affected side and RPT flexion (r(s)=-0.39, p <0.001) of the contralateral side. The results of the physical performance tests also correlated with the RAND-36 Physical function (PF) score. Comorbid diseases and pain deteriorated the results of the physical performance tests and self-reported disability. Female gender deteriorated the results of the physical performance tests and the RAND-36 PF, but not the WOMAC function score. Malalignments, restriction in the flexion ROM of the knee, and the radiologic severity of knee OA did not affect self-reported disability. CONCLUSION: Pain, BMI, and antero-posterior laxity of the knee joint were major attributes of self-reported disability. The negative effect of comorbid diseases and female gender on health-related quality of life was significant. The results of objectively measured physical performance tests correlated with self-reported disability.

Eight-year trajectories of changes in health-related quality of life in knee osteoarthritis: Data from the Osteoarthritis Initiative (OAI).

BACKGROUND: Knee osteoarthritis (OA) worsens health-related quality of life (HRQoL) but the symptom pathway varies from person to person. We aimed to identify groups of people with knee OA or at its increased risk whose HRQoL changed similarly. Our secondary aim was to evaluate if patient-related characteristics, incidence of knee replacement (KR) and prevalence of pain medication use differed between the identified HRQoL trajectory groups. METHODS: Eight-year follow-up data of 3053 persons with mild knee OA or at increased risk were obtained from the public Osteoarthritis Initiative (OAI) database. Group-based trajectory modeling was used to identify patterns of experiencing a decrease of ≥10 points (Minimal Important Change, MIC) in the Quality of Life subscale of the Knee injury and Osteoarthritis Outcome Score compared to baseline. Multinomial logistic regression, Cox regression and generalized estimating equation models were used to study secondary aims. RESULTS: Four HRQoL trajectory groups were identified. Persons in the 'no change' group (62.9%) experienced no worsening in HRQoL. 'Rapidly' (9.5%) and 'slowly' worsening (17.1%) groups displayed an increasing probability of experiencing the MIC in HRQoL. The fourth group (10.4%) had 'improving' HRQoL. Female gender, higher body mass index, smoking, knee pain, and lower income at baseline were associated with belonging to the 'rapidly worsening' group. People in 'rapidly' (hazard ratio (HR) 6.2, 95% confidence interval (CI) 3.6-10.7) and 'slowly' worsening (HR 3.4, 95% CI 2.0-5.9) groups had an increased risk of requiring knee replacement. Pain medication was more rarely used in the 'no change' than in the other groups. CONCLUSIONS: HRQoL worsening was associated with several risk factors; surgical and pharmacological interventions were more common in the poorer HRQoL trajectory groups indicating that HRQoL does reflect the need for OA treatment. These findings may have implications for targeting interventions to specific knee OA patient groups.

Physical function and properties of quadriceps femoris muscle in men with knee osteoarthritis.

OBJECTIVES: To examine the objective physical function of the lower extremities, to measure the properties of quadriceps femoris muscle (QFM), and to assess subjective disabilities in men with knee osteoarthritis (OA) and to compare the results with those obtained from age- and sex-matched control subjects. DESIGN: Cross-sectional study. SETTING: Rehabilitation clinic in a university hospital. PARTICIPANTS: Male volunteers (n=54) (age range, 50-69y) with knee OA and randomly selected healthy, age- and sex-matched control subjects (n=53). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Physical function evaluated with a test battery including the QFM composition measurement, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the RAND 36-Item Short-Form Health Survey, version 1.0. RESULTS: Knee OA patients had 13% to 26% poorer (P range, .050-.001) physical function and muscle strength compared with the controls. There were also significant differences in QFM composition. WOMAC (P range, .050-.001) and muscle strength (P<.001) associated with physical function tests, but subjective pain correlated with neither physical function nor muscle strength in knee OA patients. The radiographic knee OA grade did not have any significant effect on physical function, but passive knee motion, knee extension strength, and WOMAC were related to the severity of the disease (P<.05). CONCLUSIONS: The patients with knee OA exhibited impaired physical function and muscle strength and QFM composition compared with healthy controls. The severity of radiographic knee OA clearly had adverse effects on functional ability at the later stages of the disease. The results highlight the effect of QFM strength on physical function as well as the importance of patient's subjective and objective physical function when deciding on knee OA treatment policy.

Factors affecting self-reported pain and physical function in patients with hip osteoarthritis.

OBJECTIVE: To determine the factors associated with self-reported pain and physical function in patients with hip osteoarthritis (OA). DESIGN: Cross-sectional study. SETTING: Rehabilitation clinic in a Finnish hospital. PARTICIPANTS: Participants with hip OA (N=118; 35 men, 83 women; age, 66.7+/-6.5y; range, 55-80y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Self-reported pain and self-reported disease-specific physical function were recorded by using the Western Ontario McMaster Universities Osteoarthritis Index. Self-reported generic physical function was analyzed by using the Finnish version of the RAND 36-Item Short-Form Health Survey. As listed in the International Classification of Functioning, Disability and Health model, the effects of personal factors (age, sex, education, depression, life satisfaction, smoking, years of sporting activities), pathophysiologic factors (radiologic score of hip OA, body mass index [BMI], comorbidities, duration of knee pain) and body functions and structures (measurement of leg extensor power, passive internal rotation and flexion of the hip joint, the six-minute walk test [6MWT], Timed Up & Go [TUG] test, ten-meter walk test, sock test) were analyzed. RESULTS: The educational level (r=-.264, P<.001), comorbidities (r=.313, P<.001), and BMI (r=.252, P<.001) were identified as significant factors for self-reported disease-specific physical function as well as the educational level (r=.291, P<.001), life-satisfaction (r=-.319, P<.001), BMI (r=-.290, P<.001), and comorbidities (r=-.220, P<.005) for the self-reported generic physical function. No direct relationship with the pain and psychologic factors was detected. The number of comorbidities and duration of knee pain and life satisfaction explained 22% of self-reported pain. The number of comorbidities, passive hip flexion, and the TUG test explained 20% of self-reported disease-specific physical function whereas the passive hip flexion, 6MWT, and educational level explained 25% of self-reported generic physical function. CONCLUSIONS: Educational level, life satisfaction, and number of comorbidities were identified as significant factors for both self-reported pain and physical functioning in hip OA. Performance measures are better predictors of physical function than pain in hip OA. Factors explaining disability and pain in hip OA are multidimensional and no single predicting factor was found to be superior to any other.