Efficacy of continuous catheter analgesia of the sciatic nerve after total knee arthroplasty.

Abstract

This study investigated and compared the outcomes after continuous femoral nerve block alone, continuous femoral nerve analgesia combined with single-shot sciatic nerve analgesia, and continuous femoral and sciatic nerve analgesia in patients with total knee replacement. The retrospective study evaluated three groups: continuous femoral nerve analgesia alone, continuous femoral nerve analgesia combined with single-shot sciatic nerve analgesia and continuous femoral nerve analgesia combined with continuous sciatic nerve analgesia. All patients had a hemi- or total knee arthroplasty (TKA), which were performed by a single surgeon. The postoperative analgesia was managed by the same team. A total of 362 patient charts were evaluated from the years 2005-2012. Pain scored with a visual analogue scale (VAS) was recorded 8 hours and 24 hours postoperatively on a standardised form. The amount of opioids required with and without additional sciatic nerve analgesia was documented by monitoring the VAS. Overall, 364 patient files could be assessed. The VAS scores after 8 and 24 hours of patients with an additional continuous sciatic nerve catheter were lower (mean values 1.8 and 4.0, respectively) than those of patients with a continuous femoral catheter alone (mean values 2.7 and 4.9). After 8 and 24 hours, patients with a continuous sciatic nerve catheter had lower VAS scores than those with additional single-shot sciatic nerve anaesthesia (mean values 1.9 and 4.5). Pethidine consumption in the continuous sciatic nerve catheter group was lower (32% of patients) as compared with the two other groups (65%). The side effects of opioids per group consequently were also lower: 24% patients with side effects in the continuous sciatic nerve block group, 52% in the additional single shot sciatic nerve group, 44% in the femoral nerve block group. On the basis of these results, which correspond well to other studies of a topic that is under discussion in the literature, we adapted our postoperative pain regimen to continuous sciatic and femoral nerve analgesia for at least 24 hours after hemi- and total knee replacement.