[Continuous vs. intermitent intravenous analgesia for primary total knee replacement: analysis of the quality of the pain control, hospital stay and costs].

BACKGROUND: The International Association for the Study of Pain (IASP) defines pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Total knee arthroplasty is one of the orthopedic surgeries that manifests more pain in the first 24-48 hours, needing a multimodal analgesic therapy. The objective of this work is to compare two different intravenous analgesic modes applied to patients undergoing a primary total knee arthroplasty, analyzing the quality of pain control, hospital stay and costs. MATERIAL AND METHODS: Simple blind, comparative and prospective study comprised of 42 patients operated of total knee arthroplasty secondary to degenerative arthritis in the period between May 2016 and May 2017. RESULTS: The distribution of pain showed significant differences (p 0.0401) between both groups, indicating that the application of continuous pump for analgesia controls this symptom early. The hospital stay, on average, was different in the groups (p = 0.001), estimating about 15 hours less following the use of continuous pump. This strategy is globally more economic. DISCUSSION: The continuous infusion pump of analgesia compared with intermittent formal intravenous regimen showed better control of pain, decreasing the perception of pain by the patient, bettering the tolerance to physical therapy and reducing, on average, 15 hours of hospital stay, and thus, the final costs of the surgery.