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D. Monica Vidhya1, T. Ramalingam2, C. Srikesavan3, S. Sabapathy4
1Ganga Medical Centre & Hospitals Pvt Ltd., Department of Physiotherapy, Coimbatore, India, 2Sarvajanik College of Physiotherapy, Department of Physiotherapy, Surat, India, 3University of Oxford, Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences (NDORMS), Oxford, United Kingdom, 4Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital Major Trauma Centre, Oxford, United Kingdom
Background: The Oxford Knee Score (OKS) is a widely used self-reported outcome measure in people with different knee conditions. It has 12 questions that measure self-reported knee pain and difficulties in everyday tasks. Each question is scored from 0 to 4 for a summary score between 0 and 48. Higher scores mean better outcome. The Tamil OKS was developed following the linguistic and cultural validation methodology recommended by the Oxford University Innovation Limited, United Kingdom. The questionnaire was culturally adapted and pilot tested in 5 people to produce the final version.
Purpose: To determine the feasibility, internal consistency, factorial and convergent validity of the Tamil OKS.
Methods: Tamil speaking adults diagnosed with knee osteoarthritis and attending physiotherapy sessions at the Ganga Medical Centre & Hospitals in Coimbatore, South India were recruited. All participants provided signed consent before participation.
Participants were asked to complete the following questionnaires in paper format: Tamil OKS, Tamil Knee Injury and Outcome Score (KOOS), Tamil Health Assessment Questionnaire (HAQ) and Tamil EuroQoL-5D (EQ-5D). The KOOS has five sub-scales that measure pain, symptoms, difficulty in everyday and recreational activities, and quality of life. The HAQ measures upper and lower limb function in common activities of daily living. The EQ-5D measures state of health across five areas of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.
Feasibility was assessed by the number of missing responses across OKS items. Cronbach's alpha was used to evaluate the reliability or internal consistency of items of Tamil OKS. Spearman correlation coefficient (r) was used to determine the magnitude of association between OKS, KOOS, HAQ and EQ-5D. Principal component analysis with varimax rotation method was used to demonstrate factorial validity.
Participants were asked to complete the following questionnaires in paper format: Tamil OKS, Tamil Knee Injury and Outcome Score (KOOS), Tamil Health Assessment Questionnaire (HAQ) and Tamil EuroQoL-5D (EQ-5D). The KOOS has five sub-scales that measure pain, symptoms, difficulty in everyday and recreational activities, and quality of life. The HAQ measures upper and lower limb function in common activities of daily living. The EQ-5D measures state of health across five areas of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.
Feasibility was assessed by the number of missing responses across OKS items. Cronbach's alpha was used to evaluate the reliability or internal consistency of items of Tamil OKS. Spearman correlation coefficient (r) was used to determine the magnitude of association between OKS, KOOS, HAQ and EQ-5D. Principal component analysis with varimax rotation method was used to demonstrate factorial validity.
Results: A total of 57 participants (males: 25%; females: 75%) with a mean age (standard deviation, SD) of 58.4 (6.3) years took part. 66% of the participants had bilateral knee osteoarthritis. The duration since diagnosis of arthritis ranged from less than three months to above two years.
The OKS scores ranged between 7 and 48 with a mean (SD) score of 28.6 (9.3). The questionnaire demonstrated excellent internal consistency with a Cronbach’s alpha of 0.87 (Confidence Interval, CI 0.85 to 0.874).
The Tamil OKS demonstrated strong correlations with all the sub-scales of the Tamil KOOS and EQ-5D index (Pearson r between 0.7 and 0.93, p=0.000). There was a moderate correlation with HAQ disability index (Pearson r = -0.5, p=0.000).
Factor analysis revealed a three-factor structure and the principal component analysis explained 65% of the total variance (Kaiser-Meyer-Olkin measure of sampling adequacy was 0.78, p =0.000). All factor loadings and communalities were above 0.4.
The OKS was completed 100% by all participants. There were no floor or ceiling effects.
The OKS scores ranged between 7 and 48 with a mean (SD) score of 28.6 (9.3). The questionnaire demonstrated excellent internal consistency with a Cronbach’s alpha of 0.87 (Confidence Interval, CI 0.85 to 0.874).
The Tamil OKS demonstrated strong correlations with all the sub-scales of the Tamil KOOS and EQ-5D index (Pearson r between 0.7 and 0.93, p=0.000). There was a moderate correlation with HAQ disability index (Pearson r = -0.5, p=0.000).
Factor analysis revealed a three-factor structure and the principal component analysis explained 65% of the total variance (Kaiser-Meyer-Olkin measure of sampling adequacy was 0.78, p =0.000). All factor loadings and communalities were above 0.4.
The OKS was completed 100% by all participants. There were no floor or ceiling effects.
Conclusion(s): The Tamil OKS was shown to be a feasible and valid outcome measure.
Implications: The Tamil Oxford Knee Score was feasible to administer and has acceptable validity for use in Tamil speaking patients with knee osteoarthritis.
Funding, acknowledgements: No funding.
Keywords: Tamil Oxford Knee Score, Validation, Tamil Nadu, South India
Topic: Musculoskeletal: lower limb
Did this work require ethics approval? Yes
Institution: Ganga Medical Centre & Hospitals Private Limited, Coimbatore, India
Committee: Institutional Review Board
Ethics number: 43172
All authors, affiliations and abstracts have been published as submitted.
