Acceptability, Reliability and Validity of The Turkish Version of The De Morton Mobility Index in Elderly Patients with Knee Osteoarthritis

Abstract

Introduction: The de Morton Mobility Index is a newly developed instrument that assesses the mobility in elderly. The aim of the study was to translate the de Morton Mobility Index into Turkish and investigate its psychometric properties in elderly patients with knee osteoarthritis.

Materials and Method: The Turkish version of the de Morton Mobility Index was developed using the forward-backward translation method. Patients (n= 100) were assessed using the Turkish version of the index, Western Ontario and McMaster Universities Osteoarthritis Index, and Timed Up and Go test. Acceptability was assessed in terms of refusal rate, and administration time. Floor and ceiling effects and skew of the distribution were measured. Intra-class correlation coefficients, standard error of measurement, and minimal detectable change scores were calculated. The Pearson's correlation coefficients were measured.

Results: Average time to complete the index was 7.8 minutes. The response rate was 99%. The reliability analyses were conducted with 40 patients. The intra-class correlation coefficient( 2,1), standard error of measurement, minimal detectable change90, and minimal detectable change95 were 0.95, 3.15, 7.33, and 8.71, respectively. The de Morton Mobility Index scores were normally distributed, and had no floor or ceiling effects. Ninety-nine knee osteoarthritis patients were analyzed for validity. Correlation coefficients between the de Morton Mobility Index, Timed Up and Go test and the Western Ontario and McMaster Universities Osteoarthritis Index physical function, pain and stiffness subscales were -0.69, -0.70, -0.39, and -0.32, respectively.

Conclusion: The Turkish version of the de Morton Mobility Index is an acceptable, reliable and valid measure for assessing mobility in elderly patients with knee osteoarthritis.