Current Use of Patient-Reported Outcome Measures Ignores Functional Demand.

Introduction: Patient-reported outcome measures (PROMs) are used in orthopaedic surgery to measure aspects of musculoskeletal function that are important to patients, such as disability and pain. However, current assessments of function using PROMs do not necessarily consider a patient's functional demands in detail. A patient's functional demands could serve as a confounder to their perception of their functional ability. Hence, functional demands may need to be adjusted for when PROMs are used to measure musculoskeletal function.

Methods: We conducted a cross-sectional study in which new orthopaedic patients completed a questionnaire regarding demographics, function [Patient-Reported Outcomes Measurement Information System], functional demand (Tegner Activity Level Scale), pain self-efficacy, and symptoms of depression. 169 eligible patients with diverse orthopaedic conditions were enrolled in the study from an orthopaedic clinic, and 19 were excluded for incomplete questionnaires.

Results: The mean Patient-Reported Outcomes Measurement Information System score was 36.5 ± 9.1, and the mean Tegner score was 2.6 ± 2.0. In the multivariable regression model, patient-reported function was significantly associated with functional demand (β = 0.17, P < 0.001). Significant associations were observed for pain self-efficacy (β = 0.15, P < 0.001), acuity (β = -0.10, P = 0.004), and age 80 years or older (β = -0.16, P = 0.004). No notable association was observed with depression or age 65 to 79 years.

Discussion: Higher patient-reported physical function is associated with higher levels of functional demand when controlling for psychosocial factors, acuity, and age. Because of its confounding effect on measuring physical function, functional demand should be assessed and included in models using PROMs before and after surgery. For example, payment models using improvements in PROMs, such as the short form of the Hip dysfunction and Osteoarthritis Outcome Score and the Knee injury and Osteoarthritis Outcome Score after joint arthroplasty, should include functional demand in the model when assessing quality of care.

Level of evidence: Level II.