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.

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.

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.

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.

Lower impulsive loadings following intensive weight loss after bariatric surgery in level and stair walking: a preliminary study.

BACKGROUND: There are currently very few of studies which have evaluated the role of bariatric surgery in joint loadings and changes in gait. We wanted to examine how impulsive loading would change level and stair walking in severely or morbidly obese subjects after they had undergone bariatric surgery and weight loss. METHODS: Thirteen female and three male adults aged between 30 and 63 years, cleared for Roux-en-Y gastric bypass, were recruited into this study. All subjects were severely or morbidly obese i.e., body mass index was >35 kg/m(2). The measurement methods consisted of triaxial skin mounted accelerometers and ground reaction force (GRF); conducted at two different predetermined gait speeds. RESULTS: The average weight loss was 27.4 (SD8.7) kg after 8.8 (SD3.9) months of follow-up period. Most of the absolute GRF parameters decreased in proportion to weight loss. However, medio-lateral GRF parameters decreased more than expected. The general trend in the knee accelerations demonstrated lower impulsive loadings in both axial and horizontal directions after weight loss. We did not observe any significant changes in stair walking. CONCLUSIONS: Weight loss after bariatric surgery not only induces a simple mass-related adaptation in gait but also achieves mechanical plasticity in gait strategy.

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.

Kinematic and kinetic changes in obese gait in bariatric surgery-induced weight loss.

This study examines the effects of a radical bariatric surgery-induced weight loss on the gait of obese subjects. We performed a three-dimensional motion analysis of lower limbs, and collected force platform data in the gait laboratory to calculate knee and hip joint moments. Subjects (n=13) performed walking trials in the laboratory before and 8.8 months (SD 4.2) after the surgical procedure at two gait speeds (1.2m/s and 1.5m/s). The average weight loss was 26.7kg (SD 9.2kg), corresponding to 21.5% (SD 6.8%) of the initial weight. We observed a decrease in step width at both gait speeds, but no changes in relative double support or swing time or stride length. A significant decrease was noted in the absolute values of peak knee abductor, peak knee flexor and peak hip extensor moments. However, the moment values normalized by the body weight and height remained unchanged in most cases. Thus, we conclude that weight loss reduces hip and knee joint moments in proportion to the amount of weight lost.

Economic evaluation of multidisciplinary rehabilitation after primary total knee arthroplasty based on a randomized controlled trial.

OBJECTIVE: To conduct an economic evaluation of a multidisciplinary, biopsychosocial outpatient rehabilitation program implemented 2-4 months after total knee arthroplasty (TKA), compared with conventional orthopedic care. METHODS: After surgery, 86 patients were randomized to a multidisciplinary rehabilitation group (n = 44) or a conventional orthopedic care group (n = 42). Alongside the randomized controlled trial, we estimated the costs of rehabilitation, health care resource use, and community support. Information about resource use was collected by means of a questionnaire together with data from hospital records. The primary outcome (effectiveness) measure was change in self-reported functional capacity and the secondary measure was quality-adjusted life years (QALYs) gained during the 12-month followup. Cost-effectiveness was assessed from between-group differences in costs, change in functional capacity, and QALYs gained. RESULTS: Both protocols of providing rehabilitation services turned out to be equally effective, but the conventional orthopedic care protocol was unequivocally cost saving: the saving was €1,830 per patient (95% confidence interval -548, 3,623) using the available direct cost data. CONCLUSION: Multidisciplinary rehabilitation for unselected osteoarthritis patients in the subacute period of recovery after TKA is not a cost-effective use of health care resources. Similar rehabilitation protocols cannot be recommended for clinical pathways of TKA in the future.

Outcomes of primary total knee arthroplasty: the impact of patient-relevant factors on self-reported function and quality of life.

PURPOSE: To identify factors associated with functional recovery and outcome 1 year after total knee arthroplasty (TKA). METHODS: In the prospective follow-up study, all the patients (n = 75, aged 60-80 years) underwent primary TKA. Assessments were performed preoperatively and 12 months after surgery. The main measures were the Western Ontario and McMaster Universities OA Index (WOMAC) and the 15D. The clinical examination included analyses of comorbidity and a detailed knee examination. Age-standardised population values of the 15D and the Outcome Measures in Rheumatology-Osteoarthritis Research Society International (OMERACT-OARSI) criteria were used as indices of response. RESULTS: Osteoporosis, pain, gender, age and preoperative function of the opposite knee accounted for 29.9% of the variance in the change in the WOMAC function score. A preoperative score of the 15D below the age-standardised population level, pain, higher age and pulmonary disease reduced the possibility to reach the HRQOL level of the general population. Osteoporosis decreased the likelihood of achieving responder status according to the OMERACT-OARSI criteria. CONCLUSION: The baseline preoperative score of the 15D strongly associated with the achieved level of HRQOL after TKA. The findings of the present study highlight the multifactorial nature of health status in TKA.

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.

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.

Low metacarpal index predicts hip fracture: a prospective population study of 3,561 subjects with 15 years of follow-up.

BACKGROUND: Metacarpal index (MCI), measured from hand radiographs as the ratio between combined cortical thickness and bone diameter, has been suggested for assessment of bone mass and risk of osteoporotic fracture. We studied MCI for its ability to predict hip fractures. METHODS: Hand radiographs were taken and MCI determined in 3,561 subjects from a representative population sample of 8,000 Finns who were 30 years of age or over in 1978-80. Record linkage to the National Hospital Discharge Register identified 117 subjects who had been hospitalized for primary treatment of hip fracture by the end of 1994. RESULTS: High age, low body mass index, tall stature and smoking at baseline showed, independently of each other, significant associations with low MCI. Low MCI was a strong predictor of hip fracture. When adjusted for all potential confounding factors, the relative risk of hip fracture per decrement of MCI by one standard deviation (0.1) was 1.5 (95% CI 1.2-1.8). INTERPRETATION: Low MCI is associated with known risk factors of osteoporosis and predicts hip fracture. Since hand radiographs are easily available at low cost, measurements of MCI can be used as an alternative approach to find osteoporotic individuals with a high risk of hip fracture.

Osteoarthritis in the carpometacarpal joint of the thumb. Prevalence and associations with disability and mortality.

BACKGROUND: This study was designed to investigate the prevalence of osteoarthritis in the carpometacarpal joint of the thumb in adults thirty years of age or older in Finland. METHODS: Between 1978 and 1980, a representative population sample of 8000 Finns thirty years of age or older were invited to have a comprehensive health examination; 90% accepted. Hand radiographs were made of 3595 subjects. Since the examination, the subjects have been followed systematically to assess work disability and mortality by reviewing registers covering the whole population. RESULTS: The age-adjusted prevalence of thumb carpometacarpal osteoarthritis of Kellgren grade 2, 3, or 4 was 7% for men and 15% for women. After adjustment for age, sex, and other alleged risk factors, body mass index was found to be directly proportional to the prevalence of thumb carpometacarpal osteoarthritis in both sexes. The adjusted odds ratio was 1.29 (95% confidence interval, 1.15 to 1.43) per 5-kg/m(2) increment in body mass index. No significant association was found between the physical workload history and thumb carpometacarpal osteoarthritis. Restricted mobility of the thumb and local tenderness and swelling were frequently found in conjunction with radiographic evidence of thumb carpometacarpal osteoarthritis. Advanced (grade-3 or 4) thumb carpometacarpal osteoarthritis predicted the total mortality rate in men (adjusted relative risk, 1.32; 95% confidence interval, 1.03 to 1.69). Radiographic signs of thumb carpometacarpal osteoarthritis did not predict work disability. CONCLUSIONS: and CLINICAL RELEVANCE: Obesity is a strong determinant of thumb carpometacarpal osteoarthritis in both sexes. The effect of thumb carpometacarpal osteoarthritis on disability and mortality in the general population is modest. Because of the rarity of ensuing disability, carpometacarpal osteoarthritis of the thumb is likely to be underdiagnosed in clinical practice.