Implementation of Group Physical Therapy for Knee Osteoarthritis: A Cluster Randomized Clinical Trial.

Importance: Group-based physical therapy (PT) for knee osteoarthritis is an effective, efficient strategy for delivering care, but little is known about optimal strategies for implementing new clinical programs like group PT. Objective: To compare 2 implementation support approaches-foundational support and a combination of foundational support and more intensive enhanced support involving individual external facilitation-for delivering group PT. Design, Setting, and Participants: This cluster randomized clinical trial was conducted from January 31, 2022, to March 18, 2024, in outpatient PT departments at Department of Veterans Affairs (VA) Healthcare sites that agreed to deliver group PT to patients with symptomatic knee osteoarthritis. Sites were randomized to receive foundational or enhanced implementation support for delivering 6 sessions of group PT over 12 months that included exercise and educational content. Interventions: The foundational support approach included self-guided tools and monthly learning collaborative calls. The enhanced support approach added tailored support (eg, external facilitation) for sites that did not meet a priori benchmarks for adoption at 6 months or sustainment at 9 months. Main Outcomes and Measures: Site-level implementation outcomes were measured during months 7 to 12 and included penetration (primary outcome, assessed as the mean number of patients enrolled per month) and fidelity (mean number of classes attended per patient, out of a maximum of 6). Generalized linear models were used to examine differences in implementation outcomes between the enhanced and foundational support arms. Results: Nineteen sites (10 enhanced support, 9 foundational support) enrolling across 3 cohorts delivered group PT to 144 patients (68 enhanced support, 76 foundational support) during months 7 to 12. Patients were predominantly male (130 [90.3%]), with a mean (SD) age of 67 (9.2) years. Mean penetration estimates were 1.0 (95% CI, 0.2-1.7) patients enrolled per month for the enhanced support and 1.0 (95% CI, 0.1-1.9) for the foundational support arm, with an estimated mean difference between arms of -0.1 (95% CI, -1.1 to 1.0) patients enrolled (P = .92). Mean fidelity estimates were 5.0 (95% CI, 4.3-5.7) classes attended per patient in the enhanced support arm and 4.1 (95% CI, 3.2-4.9) in the foundational support arm, with an estimated mean difference between arms of 0.9 (95% CI, 0.0-1.9) classes per patient (P = .06). Conclusions and Relevance: In this cluster randomized clinical trial, an enhanced implementation support approach for delivering group PT did not outperform foundational support. Penetration was modest, illustrating the challenge of fostering referrals. Trial Registration: ClinicalTrials.gov Identifier: NCT05282927.