Convergent and Known-Groups Validity and Sensitivity to Change of the Virtual Performance Measure in Patients With Hip and Knee Osteoarthritis: Longitudinal Study.

Abstract

Background: Subsequent to the COVID-19 pandemic in 2020, a different approach to health care utilization was required to improve safety and efficiency. In the postpandemic era, virtual care and remote assessment of musculoskeletal conditions has become more common, and examining the accuracy of these remote encounters remains vital. In 2023, an innovative, video-based tool-the Virtual Performance Measure (VPM)-was introduced to assess the functional difficulties of patients with osteoarthritis of the knee joint. Further validation of this tool is warranted to expand its application longitudinally and in more diverse populations.

Objective: This study examined the longitudinal validity of the VPM, a digitally based outcome tool, in patients with osteoarthritis of the hip and knee joints who had undergone arthroplasty.

Methods: Patients completed a web-based survey after watching 40 videos that demonstrated 10 functional tasks with increasing difficulty, prior to and at approximately 3-5 months following surgery. The Lower Extremity Functional Scale (LEFS) was used as the reference measure. Longitudinal convergent and known-groups validity as well as sensitivity to change were assessed.

Results: The data of 120 patients (n=80, 67% female; mean age 67, SD 9 years; n=58, 48% with hip osteoarthritis and n=62, 52% with knee osteoarthritis) were examined. There was a statistically significant improvement in both LEFS (t₁₁₉=16.04, P<.001) and VPM total scores (t₁₁₉=13.92, P<.001) over time. The correlation between the postoperative LEFS and VPM scores was higher (r=0.66; P<.001) than the correlation between the change scores of these measures (r=0.51; P<.001). The area under the curve value for the VPM's ability to differentiate between urgent and nonurgent candidates for surgery was 0.71 (95% CI 0.57-0.84). Sensitivity to change as measured by the standardized response mean was 1.27 (95% CI 1.09-1.45), indicating good ability to detect change over time.

Conclusions: The VPM demonstrated sufficient longitudinal convergent and known-groups validity as well as sensitivity to change in patients with hip and knee osteoarthritis following arthroplasty. This tool has a potential to improve the delivery of care by increasing access, reducing the frequency of in-person visits, and improving the overall efficiency of the health care system following a major surgery.