Post-operative drainage after cemented, hybrid and uncemented total knee replacement

We recorded the total and 8-hourly post-operative drainage of 100 consecutive total knee replacements (33 cemented, 35 hybrid and 32 uncemented). The cemented, hybrid and uncemented prostheses had mean total drainage of 745, 1035 and 1220 ml, respectively. The difference in drainage between cemented and both hybrid and uncemented was statistically significant (P<0.05 and P<0.001). A significantly higher percentage of drainage occurred in the first 8-h period in the hybrid and uncemented groups. Total drainage in the cemented group was lower, but occurred more slowly, with a significantly higher percentage of drainage in the 17-48-h post-operative period when compared with the uncemented group (P<0.05). Within the cemented group, posterior-stabilised implants drained significantly more than those with an AP-lipped tibial insert (P<0.05). This information has implications for planning of blood product usage and timing of drain tube removal.