Establishing the Satisfactory Patient Symptom State Thresholds for Patient Reported Outcomes After Operatively Treated Tibial Plateau Fractures

Abstract

OBJECTIVES: Define patient acceptable symptom state (PASS) thresholds and factors impacting PASS thresholds for Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) and Knee Injury and Osteoarthritis Outcome Score (KOOS) following operatively treated tibial plateau fractures. METHODS: Design: Retrospective cohort. Setting: Single Level I academic trauma center. Patient Selection Criteria: All patients (n=159) who underwent fixation of a tibial plateau fracture from 2016-2021 and completed patient reported outcome measurements (PROMs) at minimum one-year follow-up. Outcome Measures and Comparisons: PASS thresholds for global outcome (PASS-Global), pain (PASS-Pain), and function (PASS-Function) were determined using anchor-based questions such as “How satisfied are you today with your injured lower extremity?” with answer choices of very satisfied, satisfied, neutral, unsatisfied, and very unsatisfied. PASS thresholds for each PROM were calculated using three methods: 1) 80% specificity, 2) 75th percentile, and 3) Youden Index. RESULTS: 60% of patients were satisfied with their global outcome and 53% with function. Using 80% specificity, 75th percentile, and Youden Index, PASS-Global thresholds were 48.5, 44.5, and 47.9 for PROMIS-PF and 56.3, 56.2, and 56.3 for KOOS-QOL, respectively. PASS-Pain threshold for KOOS-Pain was 84.4, 80.6, and 80.6. PASS-Function thresholds were 48.9, 46.8, and 48 for PROMIS-PF and 94.1, 90.2, and 86.8 for KOOS-ADL, respectively. Younger patients, those with bicondylar fractures and infections were associated with significantly lower PASS-Pain thresholds. Schatzker II fractures, lateral column involvement, or isolated lateral approach resulted in significantly higher PASS-global and -function thresholds. CONCLUSIONS: This study defines global, functional, and pain PASS thresholds for tibial plateau fractures. Patients with bicondylar fractures, infections, and medial column involvement were more often unsatisfied. These thresholds are valuable references to identify patients who have attained satisfactory outcomes and to counsel patients with risk factors for unsatisfactory outcomes following tibial plateau fractures.