Purpose: To study the judicious use of re-infusion drains in knee replacement on a target population with strict inclusion criteria and its impact on the transfusion rate and cost savings.

Method: We devised an inclusion criterion after a preliminary study on 200 knee replacements and identified the target population likely to need transfusion after the index procedure. All bilateral total knee replacements, revision total knee replacements and primary total knee replacements were the pre-operative haemoglobin was less then 5 gm/l above the patient’s transfusion trigger were included. These criteria were further validated by retrospective application.

56 patients fulfilled the criteria and 50 patients were included in the study between September 2006 – May 2007. Male/female ratio was 18: 32. Mean age was 66.2 years. Procedure included 33 total knees, 13 bilateral and 4 revision knee replacements.

Results: The overall transfusion rates dropped to 3% (bilateral, revisions 12%) during the period of this study. Mean volume re-infused was 600 ml (0–2600). Average drop in haemoglobin was 2.9 g/dl. No adverse incidents were reported.

Prior to our study the expenditure on allogenic blood transfusion was £13,230. The estimated cost of using the re-infusion system was £6230

A saving of £ 7500 was achieved as a result of using the drain in the “at risk” patient.

Conclusion: Post-operative autologous transfusion is a safe and efficient way to reduce patient’s exposure to donor blood. Use of re-infusion drains directed at a target population reduces need for allogenic blood and is cost effective.