Assessing Construct Validity of a Pelvic Floor Symptom Scale in Females With Hip Osteoarthritis Undergoing Total Hip Arthroplasty

Background: Pelvic floor symptoms are prevalent in aging females with hip osteoarthritis, yet no pelvic floor symptom outcome measure has been validated in this population. The purpose of this study was to determine the construct validity of the Pelvic Floor Distress Inventory-Short Form 20 (PFDI-SF20) in females with hip osteoarthritis undergoing total hip arthroplasty. Convergent and discriminant validity of the PFDI-SF20 were, respectively, investigated using The International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) and the Hip Disability and Osteoarthritis Outcome Score (HOOS). Methods: Construct validity of the PFDI-SF20 was evaluated for female outpatients at a specialized hip orthopedic practice using consecutive convenience sampling (n = 34). Convergent validity was evaluated by calculating correlations between scores on the PFDI-SF20 and scores on the ICIQ-UI SF. Discriminant validity was assessed by calculating correlations between scores on the PFDI-SF20 and scores on the 5 subscales of the HOOS, as the HOOS measures pain, symptoms, activity limitations, function, and quality of life related to the hip, a body region distinct from the pelvic floor. Results: There was a significant positive relationship between the PFDI-SF20 and ICIQ-UI SF scores ( r s = 0.73, P < .001). Relationships between PFDI-SF20 scores and scores on each of the HOOS subscales, ranging from ( r s ) −0.17 to 0.41, were not statistically significant. Discussion: The PFDI-SF20 demonstrated good convergent and discriminant validity in females with hip osteoarthritis undergoing total hip arthroplasty. This is the first study to validate a pelvic floor symptom measure in a hip-specific population. It is fast, free, and easy to administer.