Abstract
BACKGROUND: This study aimed to translate, adapt, and test the psychometric properties of the Japanese version of the Victorian Institute of sports assessment for patellar tendinopathy (VISA-P-J). METHODS: This prospective cohort study registered 43 participants ≥ 18 years old with a history of painful symptoms in the inferior pole of the patella to the proximal patellar tendon lasting ≥ 1 month for patellar tendinopathy. Pain in daily life and during sports activities, symptom classification, and patient global impression of change were assessed at the baseline, 1 week, and 12 weeks. The psychometric properties, test-retest reliability, standard error of measurement, internal consistency criterion validity, construct validity, responsiveness, and interpretability, of the VISA-P-J were calculated according to the COSMIN. RESULTS: The two-way random-effects, absolute agreement intraclass correlation coefficient for test-retest reliability of VISA-P-J was 0.87 (95% confidence interval: 0.78, 0.93), and the standard error of measurement of VISA-P-J was 0.89. The Cronbach's alpha for internal consistency of VISA-P-J was 0.81. A correlation between VISA-P-J and Roel's classification, Visual Analog Scale for pain (VAS)-Active Daily Living, and VAS-Sports (r = - 0.52, r = - 0.66, r = - 0.86, p < 0.01, respectively) was observed for criterion validity. All hypotheses of the hypothesis-testing method to evaluate construct validity and responsiveness of VISA-P-J were substantiated. The minimal clinically important difference of VISA-P-J was 7 points. CONCLUSION: We demonstrated that the VISA-P-J was a reliable, valid, and responsive assessment method for individuals with chronic pain in the patellar tendon.