INTRA-OPERATIVE AND POST-OPERATIVE PREDICTORS OF LENGTH OF HOSPITAL STAY IN TOTAL KNEE REPLACEMENT PATIENTS

Abstract

In Scotland, the number of primary total knee replacements (TKRs) performed annually has been steadily increasing. Data from the Scottish Arthroplasty Project has recently demonstrated that the number of knee replacements performed annually has now outstripped the number of hip replacements. The price of the implant is fixed but the length of hospital stay (LOHS) is variable. An understanding of what currently influences LOHS may therefore be of paramount importance in order that we can influence some of these parameters, with resulting benefit to our patients as well as contributing significantly and favourably towards the health economics of this procedure. This study investigates the influence of intra- and post-operative variables on LOHS.

All patients who underwent primary unilateral TKR in the region of Fife, Scotland, United Kingdom, during the period December 1994 to February 2007 were prospectively investigated. The following intra and postoperative details were recorded: length of operation, need for urinary catheterisation, patella resurfacing, lateral release, blood transfusion, the presence of superficial or deep infection, day 1 post-operative haemoglobin and haemoglobin drop (haemoglobin drop between admission haemoglobin and day 1 post-operative haemoglobin). The data was analysed using univariate and multiple linear regression statistical analysis.

Data on LOHS was available from a total of 2105 primary unilateral TKRs. The median LOHS was 8.0 days. The highly significant intra and post-operative factors associated with an increased LOHS were lateral release, post-operative haemoglobin, blood transfusion, urinary catheterisation, deep and superficial infection. An awareness and understanding of these factors may enable us to influence them favourably with resulting reduction in the LOHS and, therefore, the associated costs.