In a double-blind, randomized study, we have compared the effects of i
v. ketoprofen 200 mg followed by 12.5 mg h(-1) over 13 h, with those o
f extradural morphine 4 mg in 32 patients after hip and knee arthropla
sty. A visual analogue scale was used to score pain before analgesic a
dministration (first complaint after operation), 1 h after and every 2
h subsequently. Pain reduction 1 h after the start of analgesia was m
ean 44% (SEM 17%) in the extradural morphine group and 54% (9%) in the
ketoprofen group (ns). There were no significant differences between
groups in pain scores, pain reduction and additional analgesia require
ment (i.v. paracetamol). Naloxone 5 mu g kg(-1) h(-1) was required for
hypercapnia exceeding 6.0 kPa in three patients in the extradural mor
phine group (vs none in the ketoprofen group; ns). There were no diffe
rences between groups in side effects, except for urinary retention, w
hich was more frequent in the extradural morphine group (P < 0.05). As
there were few differences between iv. ketoprofen and extradural morp
hine, we conclude that ketoprofen may be an efficient alternative to e
xtradural morphine after hip and knee arthroplasty.