The addition of an obturator nerve block to femoral and sciatic blockade improved post-operative analgesia following total knee replacement.

This study was designed to evaluate the efficacy and safety of two concentrations of intrathecal ropivacaine, 7.5 and 10 mg ml(-1), in patients undergoing total hip arthroplasty. One hundred and four patients, ASA I-III, were randomized to receive an intrathecal injection of one of two concentrations of isobaric ropivacaine. Group 1 (n=51) received 2.5 ml of 7.5 mg ml(-1) ropivacaine (18.75 mg). Group 2 (n=53) received 2.5 ml of 10 mg ml(-1) ropivacaine (25 mg). The onset and offset of sensory block at dermatome level T10, maximum upper and lower spread of sensory block and the onset, intensity and duration of motor block were recorded, as were safety data. Onset of motor and sensory block was rapid with no significant differences between the two groups. The median time of onset of sensory block at the T10 dermatome was 2 min (range 1-25 min) in Group 1 and 2 min (range 1-21 min) in Group 2. The median duration of sensory block at the T10 dermatome was 3.0 h (range 0.5-4.2 h) in Group 1 and 3.4 h (1.1-5.9 h) in Group 2 (P=0.002). The median duration of complete motor block was significantly prolonged (P<0.05) in Group 2 compared with Group 1 (1.9 vs 1.2 h, respectively). Anaesthetic conditions were excellent in all but one patient. Intrathecal ropivacaine, in doses of 18.75 and 25 mg, was well tolerated and provided effective anaesthesia for total hip arthroplasty.

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Intra-articular local anaesthetic agents have been shown to reduce postoperative requirements and pain scores following knee arthroscopy [1]. It has been shown that intra-articular administration of the acetylcholinesterase inhibitor neostigmine at a dose of 0.5 mg also has an analgesic effect [2]. In this prospective, randomised, double-blind study we compared the quality and duration of postoperative analgesia provided by intra-articular neostigmine alone and in combination with intra-articular ropivacaine. We compared the analgesic effect of neostigmine when administered peripherally (intra-articularly) and systemically (intramuscularly).Methods One hundred ASA 1-2 patients aged 18-60 years, undergoing unilateral knee arthroscopy, received a standardised anaesthetic. After removal of the arthroscope and wound closure, patients were randomised to one of four groups: A (control): 1 ml saline intramuscularly and 20 ml ropivacacine 0.75% intra-articularly; B: neostigmine 0.5 mg in 1 ml saline intramuscularly and 20 ml ropivacaine 0.75% intra-articularly; C: 1 ml saline intramuscularly and 20 ml ropivacaine 0.75% with neostigmine 0.5 mg in 1 ml saline, intra-articularly; D: 1 ml saline intramuscularly and neostigmine 0.5 mg in 20 ml saline intra-articularly. The tourniquet remained inflated for 5 min following installation of intra-articular drugs. ResultsThe quality of pain, as obtained from VAS scores at intervals up to 4 h after injection, was similar between all groups and the control group A. The only significant difference obtained was between group C and D after 4 h. The time from intra-articular injection to first analgesic request was not significantly improved in any group compared to the control. About half of the patients in groups B and C required extra analgesia compared to the groups A and D, but this was not statistically significant. There was no significant difference between the quality and duration of analgesia provided, or the incidence of side effects, between intramuscular or intra-articular neostigmine.Discussion The use of neostigmine to provide analgesia following knee arthroscopy when used either peripherally or systemically, with or without intra-articular ropivacaine, was found to make no significant difference to the quality and duration of analgesia, when compared to using ropivacaine alone. Neostigmine 0.5 mg was not found to be associated with any significant side effects, regardless of route used. References 1 Lyons B, Lohan D, Flynn CG, Joshi GP, O'Brien TM. Intraarticular analgesia for arthroscopic meniscectomy. British Journal of Anaesthesia 1995; 75: 552-5. 2 Yang LC, Chen LM, Wang CJ, Buerkle H. Postoperative analgesia by intra-articular neostigmine in patients undergoing knee arthroscopy.

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