Evaluation of psychometric properties of Tinetti performance-oriented mobility assessment scale in subjects with knee osteoarthritis

Abstract

Objective: The objective of this study was to determine the psychometric properties of the Tinetti Performance-Oriented Mobility Assessment (POMA) scale to measure balance and gait impairments in individuals with knee osteoarthritis (OA).

Methods: A convenient sample of 25 individuals with bilateral OA knee were recruited. The convergent validity was determined by correlation analysis between scores of Berg Balance Scale (BBS) with balance subscale (POMA-B) and the Timed Up and Go Test (TUGT) with gait subscale (POMA-G). The intrarater reliability [intraclass correlation coefficient (ICC 3,1)], the Bland-Altman plots limits of agreement (LOA), the standard error of measurement (SEM), minimum detectable change (MDC) and ceiling/floor effects were determined.

Results: Score of BBS was significantly correlated with POMA-B scores, r_s = 0.63, p = 0.001, whereas TUGT showed a negative correlation with POMA-G, r_s = -0.481, p = 0.020, showing moderate convergent validity. ICC results of the total POMA scale (POMA-T), POMA-B, and POMA-G were 0.96, 0.93, and 0.96, respectively, indicating high test retest reliability. SEM, for POMA-T, POMA-B, and POMA-G was 0.35, 0.27, and 0.35, respectively; MDC values were 0.97 for POMA-T, 0.75 for POMA-B, and 0.63 for POMA-G.

Conclusion: The findings indicate that the POMA is a valid and reliable tool to assess balance and gait impairments in people with OA knee.

Keywords: balance; gait; impairment; outcome; reliability; validity.

Figure 1.

Protocol of the study design. BBS = Berg Balance Scale; NPRS = Numeric Pain Rating Scale; OA = osteoarthritis; POMA = Performance-Oriented Mobility Assessment scale; TUGT = Timed Up and Go Test; WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index.

Figure 2.

Bland–Altman plot of agreement between test and retest of POMA-B scores. The figure reveals that only 1 data point lies outside +1.96 SD. POMA-B = Performance-Oriented Mobility Assessment scale–balance subscale; SD = standard deviation.

Figure 3.

Bland–Altman plot of agreement between test and retest of POMA-G scores. The figure reveals that 2 data points were outside +1.96 SD and 1 data point was outside −1.96 SD. POMA-G = Performance-Oriented Mobility Assessment scale–gait subscale; SD = standard deviation.

Figure 4.

Bland–Altman plot of agreement between test and retest of POMA-T scores. The figure reveals that all data points are within ±1.96 SD. POMA-T = Performance-Oriented Mobility Assessment scale–total scale; SD = standard deviation.