Variation in outcomes and number of visits following care guideline implementation: Part 2 of an Analysis of 12,355 patients after total knee arthroplasty.

OBJECTIVE: To describe the variation in outcomes and number of visits before and after implementing a care guideline for total knee arthroplasty (TKA) rehabilitation. DESIGN: Non-randomized intervention study METHODS: We compared 2,558 patients with TKA who received care that was not standardized (Non-Care Guideline [NCG] group) to 9,797 patients with TKA who received care according to the care guideline (CG). We fit two Bayesian hierarchical linear regression models using the Knee Outcome Survey - Activities of Daily Living (KOS) change score and number of physical therapy (PT) visits as the response variables, controlling for relevant predictor variables. We also compared the ratio of the standard deviations of the KOS change scores and number of PT visits within and between clinics. RESULTS: The overall estimated mean improvement in KOS change score was 23.0 points (95% CI: 20.3-25.7) in the NCG group and 28.7 points (27.5-29.7) in the CG group; the mean difference was 5.6 (2.7-8.6). Mean KOS change scores were higher in the CG than NCG groups in every clinic, although only eight clinics improved significantly. Number of PT visits did not change meaningfully (NCG: mean 10.7 [95% CI, 9.9-11.5]; CG: 10.5 [9.9-10.9]). Variation in KOS change score decreased by 4% within clinics (CG:NCG ratio: 0.96 [95% CI, 0.93-0.99]) and 63% between clinics (CG:NCG ratio: 0.37 [0.21-0.62]). Variation in number of visits decreased by 7% within clinics (CG:NCG ratio: 0.93 [0.90-0.96]) and 19% between clinics (CG:NCG ratio: 0.81 [0.39-1.49]). CONCLUSION: Implementing a care guideline for TKA rehabilitation may improve outcomes and reduce unwarranted variation in practice within clinics and especially between clinics within a large healthcare system.