Transfusion needs in hip and knee arthroplasty.

A 12 months retrospective study of cross-match and transfusion practice in hip and knee arthroplasty in a general orthopaedic unit was carried out aiming to assess the transfusion needs for these procedures prior to enrolling future patients in a pre-donation program for autologous transfusion. The study revealed acceptable transfusion practice in the unit. For both procedures, over 75% of all transfusions were carried out in the peri-operative period. Eighty-nine percent of patients undergoing hip arthroplasty required transfusion with a maximum of three units, while a maximum of only two units were needed to meet the transfusion requirements of 86% of patients undergoing knee arthroplasty. In hip arthroplasty, the overall transfusion index (Ti), was 2.05, and this value did not vary significantly according to preoperative haemoglobin values. This was in contrast to knee arthroplasty, where the Ti was 2.9 in patients with preoperative haemoglobin value less than 11 g/dL compared to only 0.6 for haemoglobin value greater than 13 g/dL. In conclusion, in an autologous transfusion program, the availability of three units would satisfy the transfusion needs in 89% of hip arthroplasties, while the availability of two units would satisfy the needs in 86% of knee arthroplasties. Preoperative donation for knee arthroplasty with a haemoglobin level over 13 g/dL may prove wasteful as in our current practice, the transfusion index in this group of patients was only 0.6.