Avoidance of activity and limitations in activities in patients with osteoarthritis of the hip or knee: a 5 year follow-up study on the mediating role of reduced muscle strength.

OBJECTIVE: To evaluate the mediating role of reduced muscle strength in the relationship between avoidance of activity and limitations in activities in patients with knee or hip osteoarthritis (OA). METHODS: A longitudinal cohort study with 5 years follow-up was conducted. Patients with knee or hip OA (n = 288) were recruited at rehabilitation centers and hospitals. Self-reported and performance based limitations in activities, avoidance of activity and muscle strength were assessed at baseline, 1, 2, 3 and 5 years follow-up. Generalized Estimating Equations (GEE) analyses were used to evaluate mediation. RESULTS: In patients with knee OA, reduced knee extensor muscle strength mediated the relationship between avoidance of activity and limitations in activities. In patients with hip OA reduced hip abductor muscle strength mediates the relationship between avoidance of activity and limitations in activities. CONCLUSION: The results of this longitudinal study support the theory that avoidance of activity leads to deterioration of muscle strength and consequently to more limitations in activities in patients with knee and hip OA.

The course of limitations in activities over 5 years in patients with knee and hip osteoarthritis with moderate functional limitations: risk factors for future functional decline.

OBJECTIVE: To describe the course of limitations in activities over 5 years follow-up and identify predictors of future limitations in activities in elderly patients with osteoarthritis (OA) of the hip or knee with moderate functional limitations. METHOD: A longitudinal cohort study with 5 years follow-up was conducted. Patients (n=288) were recruited at rehabilitation centers and hospitals. The main outcome measures were self-reported and performance-based limitations in activities. Prognostic factors were demographic and clinical data, body functions, comorbidity, cognitive functioning, avoidance of activity and social support. Measurements were conducted at baseline, 1, 2, 3 and 5 years follow-up. RESULTS: Both in patients with knee and hip OA, the course of limitations in activities remained fairly stable over a period of 5 years. Avoidance of activity, increased pain, more comorbidity, a higher age, a longer disease duration, a reduced muscle strength and range of joint motion at baseline predicted more future limitations in activities in patients with knee OA. In patients with hip OA, avoidance of activity, increased pain, more comorbidity, a higher age, a higher educational level and a reduced range of motion at baseline predicted more future limitations in activities. CONCLUSIONS: The course of limitations in activities remains fairly stable over a period of 5 years in elderly patients with hip or knee OA. However, at individual level there is considerable variation. Predictors of more future limitations in activities include avoidance of activity, increased pain, higher morbidity count, reduced range of motion, and a higher age.

Accuracy of physical and occupational therapists' early predictions of recovery after severe middle cerebral artery stroke.

INTRODUCTION: The ability of physical therapists (PTs) and occupational therapists (OTs) to predict level of outcome accurately was investigated prospectively in 91 severely disabled stroke patients with a first-ever middle cerebral artery (MCA) stroke. METHODS: Within the second and fifth week after stroke onset, 364 predictions were made by 59 PTs and 47 OTs about walking ability, dexterity, activities of daily living (ADL), need for additional care in ADL, time required to achieve independent walking ability and maximal level of ADL, and destination of discharge at six months after stroke. The functional recovery patterns of stroke patients were assessed by an independent observer. The accuracy of the therapists' predictions was compared with that of derived prediction models. In addition, the influence of characteristics of patients and therapists on the accuracy of the predictions was investigated. RESULTS: Compared to observed outcomes at six months after stroke, therapists' lowest accuracies of prediction were found for the moment at which maximal ADL score was achieved (rs = 0.07; p = NS), and highest accuracy was for level of dexterity of the hemiplegic arm (rs = 0.78; p <0.01). Therapists' predictions of functional outcome at six months tended to be too pessimistic. No significant differences were observed for dexterity and walking ability when the predictions by PTs and OTs were compared with those of regression models, whereas significant differences were found for the accuracies of OTs' and PTs' first prediction of destination of discharge and second predictions of outcome in ADL and need for additional care in ADL. No significant differences were found between the accuracy of PTs' and OTs' predictions, and their ability to predict functional outcome was not significantly influenced by the characteristics of patient and therapists. CONCLUSIONS: At two and five weeks after stroke, OTs and PTs can accurately predict level of walking ability and dexterity at six months. The prediction of time required for achieving maximal level of recovery, destination of discharge, outcome of ADL as well as need for additional care in ADL leaves room for improvement.

Monitoring nutrient transport in large rivers.

The problem of estimating nutrient transport in large rivers and the uncertainty of such load estimates was studied both empirically and theoretically. In the empirical part of the study, time series of data from the Rhine, Meuse, Vistula and Oder Rivers were examined. The results of this data analysis justify the use of linear interpolation to estimate concentrations prevailing between sampling occasions. A special study of the spatial variation of concentrations within different cross-sections of the Vistula river showed that such variation can contribute substantially to the uncertainty of load estimates. In general, however, sampling at one point in the cross-section did not result in biased load estimates. In the theoretical part of the study, simple ARMA (autoregressive-moving average) models were used to derive generally applicable formulas for the expected mean square error of load estimates based on serially dependent concentration data. These formulas were then used to estimate the uncertainty of calculated nutrient loads in the Rhine and the Vistula, respectively.