Abstract
Aim
The aim of this study was to determine the factors which were responsible for differences between patients achieving the Trust target of discharge on post-operative day 5 after a primary total knee replacement and those not achieving it, in the cohort of over 75 year olds.
Methods and Results
Of all the patients undergoing a TKR at Addenbrooke's Hospital in 2008, those over 75 were identified (n=103). From the literature pre-, intra- and post-operative factors that had previously been shown to affect length of stay were identified. Patient notes were examined for details on each of these and the patients divided into 2 groups according to whether their discharge was achieved by day 5 or not. Data from 74 operations was available at the time of submission of this abstract. Pearson's Chi-squared test, student's independent t-test or the Mann-Whitney U test were performed on the data depending on the nature of the variable analysed. The following factors were found to be significantly different between the 2 groups at the 95% confidence level: pre-operative use of a walking aid (p=0.033), pre-operative Hb (p=0.003), post-operative Hb (p=0.001), post-operative requirement of a blood transfusion, post-operative complication (p<0.001), post-operative day on which active knee flexion to 90° was achieved (p=0.003). In addition the following factors were found to be significant at the 90% confidence level: age (p=0.082), comorbidity (p=0.086), marital status (p=0.095) and mobilisation by post-operative day 2 (p=0.082)
Conclusion
Pre-operative use of any walking aid, peri-operative haemoglobin concentration and post-operative complications (including the need for a blood transfusion) seem to be the significant factors associated with a prolonged stay in hospital in the over 75 year olds. A few other factors are bordering on significance and they warrant further investigation in a larger patient cohort.
