Bleeding in Knee Arthroplasty: Age, Drained Volume, and Ischemia Time.

Drainages in primary knee arthroplasty remain unclear. Our aim is to analyze variables that may affect bleeding in knee arthroplasty (age, drained volume, and ischemia time). We included 188 knee arthroplasties, divided into three groups: conventional approach for total knee arthroplasty (TKA), minimally invasive total knee arthroplasty (MIS), and unicompartmental knee arthroplasty (UNI). Main variables analyzed for the present study were age, drained volume, and ischemia time. Other recorded variables were operated knee, pre- and postoperative hematocrit, diagnosis, comorbidities, and transfusions required. No relationship between age and drained volume was observed. However, patients younger than 70 years presented a major rate of survival curve bleeding. A statistically significant difference was found between drained volume in UNI in contrast to TKA and MIS. There was a significant relationship between time and bleeding at 24 hours postoperative, observing that the greater the bleeding, the longer it would keep bleeding (log-rank, p<0.001). No statistically significant difference was observed between ischemia time during surgery and a variation in the survival curve. In conclusion, there is a significant relationship between drained volume and time (24 hours). No relationship was found between age or ischemia time and drained volume.