Relative difference among 27 functional measures in patients with knee osteoarthritis: an exploratory cross-sectional case-control study

Abstract

BackgroundTo raise the effectiveness of interventions, clinicians should evaluate important biopsychosocial aspects of the patient’s situation. There is limited knowledge of which factors according to the International Classification of Function, Disability, and Health (ICF) are most deviant between patients with knee osteoarthritis (KOA) and healthy individuals. To assist in measures’ selection, we aimed to quantify the differences between patients with KOA and healthy controls on various measures across the ICF dimensions of body function, activity, and participation.MethodsWe performed an exploratory cross-sectional case-control study. In total, 28 patients with mild-to-moderate KOA (mean age 61 years, 64% women) referred by general physicians to a hospital’s osteoarthritis-school, and 31 healthy participants (mean age 55 years, 52% women), volunteered. We compared between-group differences on 27 physical and self-reported measures derived from treatment guidelines, trial recommendations, and trial/outcome reviews. Independent t-test, Chi-square, and Mann-Whitney U test evaluated the significance for continuous parametric, dichotomous, and ordinal data, respectively. For parametric data, effect sizes were calculated as Cohen’s d. For non-parametric data, ds were estimated by p-values and sample sizes according to statistical formulas. Finally, all ds were ranked and interpreted after Hopkins’ scale. An age-adjusted sensitivity-analysis on parametric data validated those conclusions.ResultsVery large differences between patients and controls were found on the Pain numeric rating scale1, the Knee Injury and Osteoarthritis Scale (KOOS, all subscales)2, as well as the Örebro Musculoskeletal psychosocial scale3 (P < 0.0001). Large differences were found on the Timed 10-steps-up-and-down stair climb test4 and Accelerometer registered vigorous-intensity physical activity in daily life5 (P < 0.001). Respectively, these measures clustered on ICF as follows: 1body function, 2all three ICF-dimensions, 3body function and participation, 4activity, and 5participation.LimitationsThe limited sample excluded elderly patients with severe obesity.ConclusionsVery large differences across all ICF dimensions were indicated for the KOOS and Örebro questionnaires together for patients aged 45–70 with KOA. Clinicians are suggested to use them as means of selecting supplementary measures with appropriate discriminative characteristics and clear links to effective therapy. Confirmative studies are needed to further validate these explorative and partly age-unadjusted conclusions.

WITHDRAWN: Predictive potentials of 8 muscle strength actions, KOOS-pain, and Örebro-psychosocial difficulties on self-reported activities-of-daily-life function in patients with knee osteoarthritis: an exploratory regression-based cross-sectional study

“…The selection of the first and second candidate non-strength predictor variables (X 1 , X 2 ) was based on the following criteria: (i) bivariate current-study findings of candidates (for X 1 and X 2 ) should have significant moderate-to-high correlation with the outcome variable and lowto-moderate correlation with the strength variables (X 3i ), (ii) covering the psychosocial aspect of ICF with proven predictive capabilities (31), and (iii) documented clear case-vs-control discrimination in the prior study (40). The strength actions shown to be discriminative (on the most affected leg) in another of our case-vs-healthy control studies (28) on the same sample, were evaluated as X 3i (cf.…”

“…Before strength testing, the participants warmed up by several performance tests included in the larger study of the same sample (40). The 6-minute walk test (6MWT), a timed 10-step up-and-down stair-climb test [cf.…”

“…ref. (40) for results], and a set of 15 repetitions at low-tomoderate load on each specific exercise, were performed. Strength or concentric peak torque were recorded at 60°/s by the isokinetic mode applying the reliable Biodex® System 4 Dynamometer [Biodex Medical Systems, NY, USA] (52,53).…”

Relative difference in muscle strength between patients with knee osteoarthritis and healthy controls when tested bilaterally and joint-inclusive: an exploratory cross-sectional study

“…To enable appropriately judging the background variables (demographics, personal, and clinical factors) and the warm up procedures of the present study, we present below supplementary measures mainly presented in Table 1 (Results) and another study in the present journal [25].…”

“…In the week thereafter, in the lab, we registered personal or demographic characteristics, degree of radiographic KOA (radiology reports) [17], the 6MWT [34, 35], and the T10StUpDwT [33, 34, 36]. (The latter tests were embedded as a strength warm-up procedure and their results are reported elsewhere [25]. ) At the end of the lab-session, we measured peak strength.…”