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. Author manuscript; available in PMC: 2017 Dec 11.
Published in final edited form as: JAMA Surg. 2017 Jan 18;152(1):e164225. doi: 10.1001/jamasurg.2016.4225

Figure 4. Subgroup Analysis of Total Knee Replacement at 12 Months.

Figure 4

Odds ratios (ORs) are shown for the intervention vs control groups at each level of age, sex, Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) score (range, 0–100, with higher scores indicating increased pain, stiffness, and functional limitations), and baseline willingness, adjusted for site. P values for interaction were calculated from logistic regression models including the study group, the covariates and their interaction, and site. Age and WOMAC score were continuous, and baseline willingness was ordinal. The control condition consisted of a booklet about osteoarthritis (OA) of the knee; the intervention, a video examining all treatment options for OA of the knee. ITT indicates intention to treat.