The Impact of Pre-emptive Large Doses of Methylprednisolone Combined With Gabapentin on Pain Treatment and Convalescence After Total Knee Arthroplasty in Elderly: A Double-blind Randomized Study

The aim of the study was to assess whether administration of gabapentin and methylprednisolone as "pre-emptive analgesia" in a group of patients above 65 years of age would be effective in complex pain management therapy following total knee arthroplasty (TKA).170 patients operated on due to unilateral TKA will be double-blinded randomized into two groups: the study and the controls. Exclusion criteria are: clinical situation that 1/ restricted glucocorticoid administration: diabetes type 1 and 2, CRP levels above normal values (≥5 mg/l), chronic steroid treatment, peptic ulcers treated in the past 30 days and 2/and the chronic pain in the course of gonarthrosis, high intensity requiring use opioids.

The participants of the study will be subjected to the standardized procedure of subarachnoid anesthesia with subsequent unilateral femoral nerve block at the operated side, followed by the surgical procedure - unilateral TKA. The study group will receive as "pre-emptive" analgesia a single dose of 300 mg oral gabapentin and 125 mg intravenous methylprednisolone, while the others placebo. Prior to anesthesia induction, the patients receive: anti-infection prophylactics intravenous cephazolin 2.0 g, for hemostasis control - tranexamic acid 1.0 g, an anti-emetic agent - ondansetron 8 mg. Fluid supply (crystalloids) will be standardized: 12 ml/kg in the first hour of surgery and 6 ml/kg in the following hours, packed red blood cells if blood loss exceeded 600 ml and hemoglobin concentration <10g/l during the time of operation. Pain management will be carried out based on the results of the NRS scales at rest. Every 6 hours NRS will be checked and intravenous PCA (patient-controlled analgesia) oxycodone hydrochloride, if pain was ≥4 points NRS or intravenous paracetamol, metamizole, if the pain was 2 - 4 NRS points will be administered, all pain medications will be calculated for 1 kg of body weight. In keeping with the ERAS (Enhanced Recovery After Surgery) protocol, on the day of surgery the patients will receive orally fluids and meals, will be mobilized and rehabilitated.

The study was approved by the institutional review board (nr 1072.6120.11.2020). Oral and written informed consent to participate in the study will be collected from all participants of the study. The statistical analysis of the groups will be performed to asess the demographic dates, life parameters, general condition in keeping with the ASA (American Society of Anesthesiology), POSSUM (Physiologic and Operative Severity Score for the enUmeration of Mortality and Morbidity) score, total dose of analgesic medications administered parenterally calculated for 1 kg of body mass in response to value of NRS at rest on day 0, time of administration the first dose, and duration of peripheral nerve block. On the day of surgery and on subsequent days, determinations will be made of glycemia levels and inflammatory markers: C-reactive protein (CRP) and leukocytosis levels.