Transfusion practice in primary unilateral total knee replacement arthroplasty; the need for guidelines

There are no universally accepted guidelines for blood transfusion in primary, unilateral Total Knee Replacement Arthroplasty (TKA). Transfusion is associated with post-operative infection, fluid overload and prolonged duration of hospitalisation. Due to this morbidity and reports of "inappropriate" transfusion practice, an audit of the local practice was organised, with the aim of assessing compliance to existing evidence.

A 1-year retrospective survey of blood transfusion practice was conducted for all consecutive elective, primary, unilateral TKA operations.

169 operations were performed; 96% for osteoarthritis; mean patient age was 69 years; 66% were females; 34% of the patients were transfused, 60% intra-operatively. There was no threshold of pre-operative Hb predictive of a transfusion and no significant difference in the pre-operative Hb between transfused and non-transfused groups. Only 26% of the cross-matched blood was eventually transfused. Intra-operative blood loss was negligible and only 10% of transfused patients had shown cardiovascular instability. The post-operative Hb drop was maximal at around day-4.

The lack of guidelines has led to inconsistent local transfusion practice, often with no scientific evidence to support it. In the absence of a randomised controlled trial addressing the issue, certain transfusion guidelines are suggested, based on existing indirect scientific evidence.