Analysis on hidden blood loss of total knee arthroplasty in treating knee osteoarthritis.

Background: Total knee arthroplasty (TKA) is an important therapy for the treatment of various late-stage knee diseases. However, it has been observed that patients have lower hemoglobin (HB) counts postoperatively, which are significantly inconsistent with the measured blood loss. Although the concept of hidden blood loss has been presented in 2000, very little clinical attention has been paid since then.