Fig. 3

Postoperative analgesia following total knee arthroplasty. Protocols from the in-house acute pain service from 2016 and 2018 were retrospectively evaluated. Data from patients after total knee arthroplasty with either continuous peripheral nerve block (PNB, n = 185) or i.v. patient-controlled analgesia with piritramide (Pir, n = 131), respectively, are given. The figure shows median average Numeric Rating Scale (NRS) values at rest and maximum NRS values (A, upper panels), median number of PCA bolus requests and the median ratio between requested and administered boluses (A, lower panels). In B, positive and negative feedback during regular follow-up visits (expressed as median relative frequency, upper panels) and median duration and frequency of patient visitations (lower panels) are shown. Data are visualized as violin diagrams with median and interquartile range (25–75), indicated by the dashed lines. Mann–Whitney test was used for comparison. *p < .05, ***p < .005, ns: not significant