Abstract
Urinary catheterization in the postoperative period is known to increase the risk of deep joint infection following arthroplasty. A number of studies have attempted to elucidate the individual patient factors and surgical procedural factors which predispose patients to postoperative urinary retention.
We conducted a retrospective observational study of three hundred patients to specifically determine the effect of the anaesthetic technique on the incidence of urinary retention following elective lower limb arthroplasty. One hundred consecutive patients were surveyed in each of three groups differing by the type of the anaesthetic technique and the drug administered; 1) general anaesthesia with femoral nerve block, 2) spinal anaesthesia with intrathecal fentanyl, and 3) spinal anaesthesia with intrathecal morphine.
The incidence of urinary retention requiring catheterisation in male patients receiving intrathecal morphine was 58% compared with 10% and 6% for those who had general anaesthesia with femoral nerve block and intrathecal fentanyl, respectively. This difference was statistically significant (p<0.01). The incidence of urinary retention in females across all groups was =2%. The average residual volume of urine following catheterisation was 750ml (460-1500ml).
Our findings show that the use of intrathecal morphine greatly increases the risk of postoperative urinary retention in male patients, whereas no significant increase was found amongst female patients. This risk should be carefully considered when choosing the type of intraoperative anaesthetic/analgesic combination employed in male patients and be rationalised against the intended benefits to the patient.
