The WOMAC score can be reliably used to classify patient satisfaction after total knee arthroplasty
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The primary aim of this study was to define a classification in the WOMAC score after total knee arthroplasty (TKA) according to patient satisfaction. The secondary aims were to describe patient demographics for each level of satisfaction.
A retrospective cohort consisting of 2589 patients undergoing a primary TKA were identified from an established arthroplasty database. Patient demographics, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and short form (SF) 12 scores were collected pre-operatively and 1 year post-operatively. In addition, patient satisfaction was assessed at 1 year with four responses: very satisfied, satisfied, dissatisfied or very dissatisfied. Receiver operating characteristic (ROC) curves were used to identify values in the components and total WOMAC scores that were predictive of each level of satisfaction, which were used to define the categories of excellent, good, fair and poor.
At 1 year, there were 1740 (67.5%) very satisfied, 572 (22.2%) satisfied, 190 (7.4%) dissatisfied and 76 (2.9%) very dissatisfied patients. ROC curve analysis identified excellent, good, fair and poor categories for the pain (> 78, 59–78, 44–58, < 44), function (> 72, 54–72, 41–53, < 41), stiffness (> 69, 56–69, 43–55, < 43) and total (> 75, 56–75, 43–55, < 43) WOMAC scores, respectively. Patients with lung disease, diabetes, gastric ulcer, kidney disease, liver disease, depression, back pain, with worse pre-operative functional scores (WOMAC and SF-12) and those with less of an improvement in the scores, had a significantly lower level of satisfaction.
This study has defined a post-operative classification of excellent, good, fair and poor for the components and total WOMAC scores after TKA. The predictors of level of satisfaction should be recognised in clinical practice and patients at risk of a lower level of satisfaction should be made aware in the pre-operative consent process.
Level of evidence
KeywordsWOMAC Outcome Total knee arthroplasty Classification Satisfaction
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest with the content of this study.
The data collected formed part of the study centre’s local joint registry which is registered as an ongoing service evaluation with Caldicott approval (reference number 2840). There was no additional patient contact, and as such, this project was performed as a service evaluation without the need for formal ethical approval. The project was registered with the institutions audit department (registration number 8161) and was conducted in accordance with the Declaration of Helsinki and the guidelines for good clinical practice.
The patients gave informed written consent to have their anonymised data collected onto the study centre’s registry and for analysis for service evaluation purposes.
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