Validity and Responsiveness comparison of the Knee injury and Osteoarthritis Outcome Score (KOOS) in Total Knee Replacement Patients

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Validity and Responsiveness comparison of the Knee injury and Osteoarthritis Outcome Score (KOOS) in Total Knee Replacement Patients

Total knee replacement is primarily indicated for disabling pain caused by severe arthritis. It is a complex procedure that demands a skillful removal of the diseased portions of the bone, to shape the remaining bone to lodge the knee implant.

A study by Gandek B., et. Al., aimed to estimate the validity and responsiveness of the Knee injury and Osteoarthritis Outcome Score (KOOS) in relation to other patient-reported outcome measures before and after the total knee replacement (TKR).

To compare KOOS, WOMAC and SF-36 Health Survey, pre-TKR and 6-month post-TKR data from 1,143 patients in the U.S. joint replacement cohort was used. For the evaluation of validity, multiple methods were used, incorporating correlations of pre-TKR scale scores and ANOVA models that used pre-TKR data to compare the relative validity (RV) of scales in discriminating between groups. These differed in assistive walking device use and a number of comorbid conditions. They used post-TKR minus pre-TKR change scores to estimate RV of scales in discriminating between groups rating themselves as better, same or worse (BSW) in their capability to do activities at 6 months. Effect sizes (ES) and standardized response means (SRM) was used to report the responsiveness.

The KOOS scale scores were worse for patients using an assistive device but only decreased weakly with inflating comorbid conditions in support of convergent and discriminant validity. The KOOS QOL scale was significantly (p<0.05) better than all measures excluding the SF-36 Physical Component Summary, while all knee-specific scales discriminated between BSW groups.  SF-36 measures portrayed lower ES and SRM, while KOOS QOL had the highest ES. Among BSW groups, KOOS Pain and Symptoms scales differentiated better than WOMAC Pain and Stiffness scales.

Therefore, it was concluded that the KOOS scale was valid and responsive in this cohort of U.S. TKR patients. While KOOS QOL executed particularly well in capturing aggregate knee-specific results.

Source:

Arthritis Care & Research

Link to the source:

https://www.ncbi.nlm.nih.gov/pubmed/28085998

The original title of the article:

Validity and Responsiveness of the Knee injury and Osteoarthritis Outcome Score (KOOS): A Comparative Study among Total Knee Replacement Patients

Authors

Barbara Gandek et. al

SearchTags: 
Exploratory, Arthritis, Bones, Joints
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