Multimodal Pain Management Following Total Knee And Hip Arthroplasty: Impact On Functional Outcomes

Abstract

PURPOSE: To investigate if multimodal pain medication management improves functional status and decreases opioid consumption in the inpatient subacute rehabilitation setting following total hip and knee arthroplasty. METHODS: Retrospective cohort electronic medical record analysis over a three-year period. Patients divided into 3 groups based on pain regimens: Opioid Only (O), Opioid and NSAIDS (NS), Opioid and Neuromodulators (ON). Morphine milligram equivalent (MME) doses were calculated for all opioids. Charts were evaluated for Functional Independence Measure (FIM) scores in walking, wheelchair, bathing, toilet transfer, bed transfer, and walking distance. RESULTS: A total of 161 patients were included in the study: 99 O, 43 ON, and 19 NS. The mean age of the study population was 65 years old, with 70% of patients being female, African American, and having received unilateral knee replacement surgery. There were no significant inter-group demographic differences. The ON group showed the greatest improvement in FIM scores for Walking, Wheelchair mobility, Bathing, and Bed transfers (See FIM Score table). All patients treated with multimodal pain regimens improved from walking 50-149 feet on admission to greater than 150 feet on discharge, whereas 3/17 patients treated with opiates only did not improve to walking greater than 150 feet. At discharge, the O group was using ~59 morphine milligram equivalent (MME) doses per day, whereas the ON group was using 50 MME, and the NS group was using 41.5 MME. Differences in FIM scores and MME dosing did not reach statistical significance. CONCLUSIONS: Patients treated with multimodal pain regimens achieved CDC recommended guidelines of <50 MME per day on discharge. Patients treated with opiates and neuromodulators showed the greatest functional outcome gains in 4/5 categories.