After informed consent 90 healthy America Society of Anesthesiology functional classes 1–2 patients undergoing elective Hallux Valgus surgery ad modum Turan were studied . The study protocol, a prospective randomised study of the effects of a single shot ankle block on the need for rescue analgesia during the first 24 hours following surgery was approved by Karolinska Institutet's local ethical committee. The patients were randomised into three groups by closed envelope technique;
Group A had 15 cc levo-bupivacaine 2.5 mg/ml
Group B had 15 cc lidocaine 10 mg/ml
Group C Placebo Control had 15 cc of saline
The performance of the ankle block was; "the posterior tibial nerve" by 5 cc posterior to the medial malleoli, "the peroneal nerve, superficial and deep" by 6 cc on dorsum of the foot and "the sural nerve" by 4 cc posterior to the lateral malleoli.
All patients followed the routine pre and postoperative protocol of our institution. They were asked to refrain from eating for 6 hours and drinking for 2 hour prior to surgery.
After establishment of an intravenous line all patients were given 8 mg betamethasone, 0.3 mg alfentanil and 30 – 50 mg propofol. After sedation the patients received the ankle block in accordance with the randomisation in a single blinded fashion.
All patients also had 10 cc of 10 mg/ml lidocaine subcutaneous around the surgical incision given by the orthopaedic surgeon (IT) under sterile conditions right prior to incision. A general anaesthesia was administered by means of sevoflurane in oxygen/air by mask. Sevoflurane was titrated according to clinical needs by the attending anaesthetist (JJ). Sevoflurane concentrations were continuously monitored by side-stream gas analysis. Peak end-tidal and mean end-tidal sevoflurane concentrations were recorded and used for evaluation of need for anaesthesia.
Immediately after surgery anaesthesia was discontinued and the patients moved to the recovery area, if fully awake and alert possibly bypassing conventional recovery room stay. After arrival in recovery area all patients had an initial oral dose of etoricoxib 120 mg and a loading dose of 30 mg/kg paracetamol.
Patients were discharged when awake, and ambulant with minimal and acceptable levels of subjective pain (VAS < 4).
At discharge all patients were provided with take-home analgesic medication; Etoricoxib 120 mg, paracetamol 1 gr. and dextropropoxyphene 100 mg. All patients were provided with oral and written instruction about pain management at home they were informed to take:
Regularly etoricoxib 120 mg once daily
Additional paracetamol 1 gr. oral when needed (up to four grams daily), as initial pain therapy
Additional dextropropoxyphene 100 mg oral if paracetamol had reviled pain within 30 minutes
They were instructed to take patacetamol and dextropropoxyphene not by routine, but only when needed.
Patients were instructed to fill in a protocol for the first postoperative day; 1st 24 post operative hours, need for any pain medication; paracetamol and dextropropoxyphene, as well as pain ratings at a verbal pain scale; no pain, little pain, pain, severe pain .
Patients' demographics are presented as mean and standard deviation. All results are given as median and range. None-parametric Chi-square test or Mann-Whitney U-test when appropriate studied differences between groups. The number of patients (30 in each group) was determined by a pre-study power analysis based on the findings in a pilot study in our institution; need for additional analgesics in the control (placebo) group of 70% and a clinical relevant absolute reduction in patient taking additional analgesics of 30%, corresponding to clinical significant effect of an ankle block being that only 40% of patients needing additional analgesics during the first postoperative 24 hours with a power of 90 % at p < 0.05. All statistics were made in StatView™ on a Macintosh computer system.