Abstract
Introduction
Urinary catheterisation can cause bacteraemia and therefore may be associated with a risk of infection in hip and knee arthroplasty. However postoperative urinary retention can be distressing for the patient. This study investigates the factors that might predict the need for postoperative catheterisation in order to help develop a protocol to decide who should be electively catheterised.
Methods
A prospective blinded study of 128 consecutive patients undergoing lower limb arthroplasty was carried out. No patient underwent perioperative catheterisation. Data obtained included sex, age, joint (hip or knee replacement), prostate score (IPSS), previous urinary retention, comorbidities and residual bladder volume after attempted complete voiding measured using an ultrasound bladder scanner. The type of anaesthesia and the requirement for urinary catheterisation postoperatively were recorded. Predictive risk factors were identified using binary logistic regression, and expressed as odds ratios (OR) and 95% confidence intervals (CI).
Results
The mean age was 69.5 years (SD 8.9). There were 56 males and 72 females. 38 patients (30%) required postoperative catheterisation. Logistic regression identified the following predictive risk factors: bladder scan volume per ml increase (OR 1.006; CI 1.000–1.012); male sex (OR 5.51; CI 2.01–15.16); previous catheter (OR 4.26; CI 1.53–11.82); spinal/epidural/combined spinal epidural (CSE) anaesthesia (OR 6.78; CI 1.75–26.32); moderate IPSS score (OR 5.15; CI 1.73–15.37); severe IPSS score (OR 3.53; CI 0.605–20.54). The specificity of our model is 91%, the positive predictor value 71% and negative predictor value 82%.
Discussion
Post-voiding bladder scan volume (1ml increase = 0.6% increased risk), male sex, history of retention, medium or high IPSS score and an epidural, spinal or CSE anaesthetic are independent risk factors that can be used preoperatively to predict the likelihood of postoperative retention.
