Abstract
Total knee arthroplasty had been reported to present similar amount of blood loss in external and hidden form. We studied whether lateral patellar release made any differences on both forms of blood loss.
Material and methods: We studied 91 patients (83 women an 8 men) undergoing primary unilateral total knee arthroplasty cemented posterior stabilised with patellar substitution, in 40 lateral patellar release were performed. Surgery is performed under tourniquet. The blood drain was recorded. We assumed that blood volume on the fourth postoperative day was the same as before surgery. Blood volume was estimated taking sex, body mass and height into account. Haemoglobin was recorded on preoperative and four days postoperative.
Results: We found more external blood loss in patients without lateral patellar release (p< 0,05) but no statistical differences in total and hidden blood loss. The amount of hidden blood in both groups were more than twice (975 mL) the external blood loss (443 mL). No relationship was found between body mass and any type of blood loss.
Conclusions: Lateral patellar release made no difference in the amount of total blood loss. In total knee arthroplasty hidden blood loss doubled external blood loss.
Correspondence should be addressed to Ms Larissa Welti, Scientific Secretary, EFORT Central Office, Technoparkstrasse 1, CH-8005 Zürich, Switzerland
