Open AccessInvestigating the Test–Retest Reliability and Validity of Hand-Held Dynamometry for Measuring Knee Strength in Older Women with Knee Osteoarthritis
Author(s) -
Jaclyn N. ChoppHurley,
Emily G. Wiebenga,
Anthony A. Gatti,
Monica R. Maly
Publication year - 2019
Publication title -
physiotherapy canada
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.389
H-Index - 27
eISSN - 1708-8313
pISSN - 0300-0508
DOI - 10.3138/ptc-2018-0051
Subject(s) - osteoarthritis , physical therapy , standard error , gold standard (test) , reliability (semiconductor) , medicine , physical medicine and rehabilitation , population , test (biology) , mathematics , statistics , paleontology , power (physics) , physics , alternative medicine , environmental health , pathology , quantum mechanics , biology
Purpose: Hand-held dynamometry (HHD) can be used to evaluate strength when gold-standard isokinetic dynamometry (IKD) is not feasible. HHD is useful for measuring lower limb strength in a healthy population; however, its reliability and validity in individuals with knee osteoarthritis (OA) has received little attention. In this research, we examined the test-retest reliability and validity of HHD in older women with knee OA. We also examined the associations between reliability and symptom and disease severity. Method: A total of 28 older women with knee OA completed knee extension and flexion exertions measured using HHD and IKD. Intra-class correlation coefficients (ICC 2,3 ), standard error of measurement, and minimal detectable change were calculated. Correlation coefficients and regressions evaluated the relationships between inter-trial differences and symptom and disease severity. Results: High test-retest reliability was demonstrated for both exertions with each device (ICC 2,3 = 0.83-0.96). Variance between trials was not correlated with OA symptoms. Criterion validity was good (ICC 2,3 = 0.76), but extension yielded lower agreement than flexion. Regression analysis demonstrated that true strength can be predicted from HHD measurements. Conclusions: HHD is a reliable tool for capturing knee extension and flexion in individuals with OA. Because of lower agreement, HHD might be best suited for evaluating within-subject strength changes rather than true strength scores. However, gold-standard extension strength magnitudes may reasonably be predicted from regression equations ( r 2 = 0.82).