Dynamic weight-bearing assessment of pain in knee osteoarthritis: construct validity, responsiveness, and interpretability in a research setting

Abstract

BackgroundThe Osteoarthritis Research Society International (OARSI) has suggested to asses pain after specific activities consistently in clinical trials on knee OA. The Dynamic weight-bearing Assessment of Pain (DAP) assesses pain during activity (30 s of performing repeated deep knee-bends from a standing position). The purpose of this study is to evaluate the construct validity, responsiveness, and interpretability of the DAP for knee osteoarthritis (OA).MethodsOne-hundred participants with knee OA were tested twice each with the DAP, the Knee injury and Osteoarthritis Outcome Score (KOOS), six-minute-walk-test (6MWT), and 6-min-walk-test with subsequent pain rating (6MWTpain), and once with a transition questionnaire (TRANS-Q) for the patient-reported change in pain after 12 weeks of exercise. Construct validity (baseline-scores) and responsiveness (change-scores) were estimated by Spearman Correlation Coefficients. We hypothesized that no correlations would be excellent (<0.7) (divergent validity), except for the 6MWTpain (convergent validity). The TRANS-Q was used for interpreting the DAP change-scores in terms of responsiveness and Minimal Important Change (MIC).ResultsDivergent validity with the KOOS subscales (r = −0.31 to–0.45) and the 6MWT (r = −0.25) was supported. Convergent validity with the 6MWTpain was not supported (r = 0.54). The DAP change-scores corresponded to patient-reported change in pain (TRANS-Q), while correlations with change-scores on the other instruments were <0.35. The MIC was 2.4 DAP points.ConclusionsThe DAP possesses divergent validity compared to other instruments for knee OA, supporting the potential for this new way of assessing pain directly during activity. Importantly, the DAP change-scores correspond to patient-reported changes in pain, showing responsiveness. A change of 2.4 or more can be interpreted as clinically relevant. The DAP is a promising alternative to using ‘pain on walking’ as a clinical trial inclusion criterion/outcome.

The association between histological, macroscopic and magnetic resonance imaging assessed synovitis in end-stage knee osteoarthritis: a cross-sectional study

“…0.70 based on the common application of 0.70 as cutoff: r < 0.70 for divergence and r ! 0.70 for convergence 42,43 . Thus, only correlations coefficients !0.70 were regarded as statistically significant as pre-defined in the study protocol (Appendix 2).…”

“…Performing Bonferroni correction should therefore not alter the interpretation or conclusions and a threshold of r ! 0.70 has previously been used 42,43 . Other strengths of the study include: the use of validated scoring systems for both the histological and macroscopic assessment of synovitis, the fact that biopsies were taken from six different regions covering the entire knee, the use of three different MRI techniques including two different DCE-MRI analytic approaches and the high temporal resolution of the DCE-MRI sequence.…”

Minimal important change and difference for knee osteoarthritis outcome measurement tools after non-surgical interventions: a systematic review

“…Most anchor studies (k=10) were of high quality and two were of low quality35 36 (online supplemental file 1). The quality of the consensus study (k=1) was moderate (online supplemental file 2).…”

“…All the anchor studies were observational prospective cohort studies14 15 35 37–43 and two of them were nested within randomised controlled trials36 44(table 1). The number of participants in each study ranged from 41 to 1606.…”

Quadriceps or hip exercises for patellofemoral pain? A randomised controlled equivalence trial

“…Key secondary outcomes were changes from baseline in the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire pain, physical function and knee-related quality of life subscales 28. Other secondary outcomes included changes from baseline in the KOOS sports/recreation and symptoms subscales, Pain Self-Efficacy Questionnaire,29 the EuroQoL EQ-5D-3L Questionnaire,30 assessment of pain on a 0–10 Numeric Rating Scale (NRS) during activity (30 s of performing repeated deep knee-bends from a standing position)31 and global perceived effect on overall health, pain and function measured on a 15-point Likert scale ranging from −7 (much worse) to +7 (much better). Further, isometric muscle strength of hip abductors, hip adductors, hip external rotators, hip internal rotators, hip extensors, hip flexors, knee flexors and knee extensors were measured with a handheld dynamometer.…”