A randomised controlled trial of ultrasound-guided blockade of the saphenous nerve and the posterior branch of the obturator nerve for postoperative analgesia after day-case knee arthroscopy

The purpose of this study was to investigate the effects of blockade of the saphenous nerve and the posterior branch of the obturator nerve in addition to a standard analgesic regimen for patients discharged the same day after knee arthroscopy. The primary outcome was knee pain on flexion during the first 24 postoperative hours, calculated as area under the curve. We allocated 60 patients to ultrasound-guided nerve blocks with either ropivacaine or saline, 30 to each. The median (IQR [range]) pain score on knee flexion in the ropivacaine group 2.0 (1.1-3.7 [0.1-7.1]) was not statistically different to that in the saline group (3.3 (1.7-4.6 [0.3-6.8]), p=0.06). There were no differences in pain at rest, opioid consumption or function.