Validation of the Western Ontario Meniscal Evaluation Tool (WOMET) for Patients with a Degenerative Meniscal Tear

BACKGROUND: Arthroscopic partial meniscectomy is the most common orthopaedic procedure and is often carried out to treat a degenerative meniscal lesion. The purpose of the present study was to determine the psychometric properties of the Western Ontario Meniscal Evaluation Tool (WOMET) for patients with an arthroscopically verified degenerative meniscal tear. METHODS: Four hundred and eighty-five patients with an arthroscopically verified degenerative meniscal tear were included. Two groups of patients were formed: one consisted of 385 patients for the purpose of psychometric testing of the WOMET and the other consisted of 100 patients for the assessment of criterion validity. The reliability of the WOMET questionnaire was assessed by determining both internal consistency and test-retest repeatability; for the latter, a subgroup of forty patients completed the form two weeks preoperatively and again on the day of the operation. Validity assessment included determination of content validity (floor and ceiling effects), criterion validity (completion of the WOMET, the Lysholm knee score, and a generic quality-of-life questionnaire by a group of 100 patients), and construct validity (hypothesis testing). Finally, the responsiveness of the WOMET was determined with two successive assessments (on the day of surgery and six months postoperatively). RESULTS: The WOMET showed acceptable internal consistency, test-retest reliability, floor and ceiling effects, criterion validity (agreement with both Lysholm and 15-D scores), and construct validity (all hypotheses were significant). The WOMET was also found to be responsive to change. CONCLUSION: The WOMET score demonstrated acceptable psychometric performance as a patient-administered outcome measure for patients with an arthroscopically verified degenerative meniscal tear.