A study of the noninstrumented physical examination of the knee found high observer variability

Abstract 

Objective

This study estimated the inter- and intraobserver reliability of a set of noninstrumented physical examination measures for knee pain in older adults.

Study Design and Setting

Forty-five patients from primary care, and 13 patients from secondary care, were each examined by two out of a team of three physical therapists, and were reexamined by one of these observers 1 month later. The examination items were standardized and included dichotomous, ordinal and continuous variables considered relevant to a primary care context.

Results

For individual dichotomous items, median interobserver and intraobserver agreement (κ) was 0.22 (interquartile range IQR = 0.12–0.35) and 0.41 (IQR = 0.28–0.56) respectively. For ordinally rated variables, weighted kappa ranged from −0.08 to 0.43 for interobserver agreement, and from 0.00 to 0.79 for intraobserver agreement. The median intraclass correlation coefficient for continuous examination variables was 0.80 (range 0.68–0.89) for interobserver agreement, and 0.84 (range 0.67–0.95) for intraobserver agreement.

Conclusion

For trained but nonexpert examiners, agreement was generally poor for dichotomous and ordinal examination items; however, κ-values are liable to be depressed by the low prevalence of clinical signs in this sample. Agreement on continuous variables was notably better.

Keywords: Observer variability, Reliability, Knee, Physical examination