Yoeri Bemelmans

Chapter 4 50 forms. PROMS were obtained preoperative and 3 months postoperative including the Oxford Knee Score (OKS; 12 to 60, 12 being the best outcome) [13] and Western Ontario and McMaster Universities Arthritis Index (WOMAC; 0 to 100, 100 being the best outcome) [25]. This prospective, randomized, double-blind pilot study was performed in compliance with the Helsinki Dec-laration of 1975, as revised in 2000 andwas studied and approved by the IRB (METC Atrium-Orbis Zuyd, Heerlen, the Netherlands, IRB Nr. 13T112) and registered online at the European Clinical Trials Database (EudraCT, Nr. NL 20140403), the Dutch Trial Register (www.trialregister. nl, Nr. NTR4769) and conducted in accordance with the guidelines for Good Clinical Practice (GCP). Statistical analysis Sample size and power calculations weremade based on our expectations. We assumed that both LIA with (Ropi+) or without (Ropi−) adrenaline significantly improves the mean VAS pain score by 20 mm postoperative with a stand-ard deviation of 15 mm on a VAS pain score of 100 mm. With an alpha of 0.05 and 1-beta error of 0.8, we needed 21 patients: 25 taking into account 10%lost of follow-up. This study included 50 consecutive patients, 25 in each arm. The Shapiro–Wilk test showed that the data were not normal distributed. Statistically significant differences between both groups were analysedwith nonparametric Mann–Whitney U test (e.g. VAS pain score, early mobili-zation, early discharge and PROMS), and Chi-square tests were used for categorical variables (e.g. rescuemedication use and AE’s). P value was considered to be statistically significant at P ≤ 0.05 for all analysis. All statistical analyses were performedwith use of SPSS version 17.0 for win-dows (Inc., Chicago, IL). Results are presented as either with frequencies (%), mean (SD), or median (range). Results Fifty randomized patients completed this study. None of the patients were lost to follow- up. Randomizationwas unblinded after study completion no SUSAR’s occurred. Baseline demographics and OR data were not significant different (Table 2). One patient in both groups used rescue medication on day two. Early mobilization was comparable between both groups (n.s.). Twenty-two patients (88 %) in the Ropi+ group could mobilize within a mean of 336 min (76.0) compared to 21 patients (84 %) who mobilized within a mean of 350 min (68.0) after anaesthesia in the Ropi− group. Length of hospital stay was comparable between both groups (n.s.). Twenty patients