Risks and Complications with a Blood Transfusion During Total Hip and Knee Arthroplasty

Transfusions of packed red blood cells are fairly common for patients undergoing surgery, especially for a total hip or total knee replacement, due to blood loss during the procedure. Some studies have shown rates for blood transfusion with a joint replacement to be between eighteen and sixty-eight percent. There has been a push by hospitals and orthopedic surgeons to minimize the use of blood transfusion for reasons of cost, supply concerns, inappropriate use, serious complications, prolonged hospital stay and mortality. Studies that indicate complications and overuse tend to focus on the after effects, but are not accounting for the fact that many patients requiring a blood transfusion after joint surgery are likely to have preoperative risk factors as well. To look further into this effect research needs to better understand the reasons for and the patient status prior to the transfusion in order to better understand the risks afterward. This study has been set up to try to determine, for hip and knee replacement, the preoperative factors associated with needing a blood transfusion and the onset of serious complications in the first thirty days post surgery.

The National Surgical Quality Improvement Program is a nationally validated, outcome based program which collects data about preoperative risk factors, variables during surgery, thirty-day postoperative complications and mortality rates. This database was used to identify patients undergoing elective primary hip and knee replacements in 2011. A total of 9362 hip replacements and 13,622 knee replacements were identified. Demographic characteristics such as age, sex and race were noted as well as pre surgical factors such as body mass index (BMI), diabetes mellitus, smoking, alcohol use, congestive heart failure, hypertension, bleeding disorder, and other chronic conditions. Lab values and surgical variables such as duration of the procedure and American Society of Anesthesiologists (ASA) class were noted. The thirty-day complications of interest included infection, venous thromboembolism and mortality.

For this set of patients the blood transfusion rate for hip replacement was 22.2 percent, and for total knee replacement 18.3 percent. Significant risk factors associated with needing a blood transfusion were similar for both knee and hip replacements and included (in order of importance) increasing age, preoperative hematocrit (red blood cell count), BMI 2. These results were somewhat surprising, for example the authors did not expect lower BMI to be associated with increased transfusion requirement, and they also found that smoking was actually a protective factor against needing a transfusion.

This study did not indicate that having a blood transfusion made the patient any more likely for serious complications including infection, venous thromboembolism or death. Some other studies have shown some increase in such complications with blood transfusion, but the studies mentioned here by Pedersen et al and Browne et al were smaller and limited only to total hip replacements.

In any observational study there cannot be proven causality, but the authors feel that this study has used a high quality database, large sample size and comprehensive analysis of preoperative factors, and can provide useful information. This study has shown that blood transfusion following total joint replacement is fairly common and generally safe.