Comparision of blood loss between computer assisted and conventional total knee arthroplasty

Bleeding during total knee arthroplasty (TKA) can cause significant morbidity and mortality. One proposed benefit of computer assisted TKA is decreased bleeding as the femoral canal is not invaded. This study assessed blood loss between computer assisted surgery (CAS) and conventional TKA.

73 consecutive patients (37 males, 36 females) underwent primary TKA between 2006 and 2009. Thirty eight patients underwent navigated TKA and 35 underwent conventional TKA for symptomatic osteoarthritis of the knee. These patients were matched for age, gender, and body mass index (BMI). Average age was 70.3 years (range 47-91 years). Mean BMI was 30 (range 17-49). Average preoperative hemoglobin was 13.26 g/dL (range 8.7-18.4 g/dL) in the navigated group and 13.47 g/dL (range 9.6-15.8 g/dL) in the conventional group (P = 0.9). Average tourniquet time was 110 min (range 90-150 min) in the navigated group and 96.7 min (range 60-145 min) in the conventional group (P = 0.77).

Average postoperative hemoglobin in the navigated group was 10.34 g/dL (range 7.5-14.8 g/dL) and in the conventional group was 10.03 g/dL (range 7.5-12.2 g/dL) (P = 0.17). Six patients in both groups required blood transfusions. The mean drain collection was 599 mL (range 150-1370 mL) in the navigated group and 562 mL (range 750-1000 mL) in the conventional group (P = 0.1724). These results suggest that there is no significant reduction in blood loss in CAS TKA.

These results suggest that there is no significant difference in blood loss in CAS TKA and conventional TKA. This study also highlights the heterogeneity of methods used in studies related to CAS TKA. We believe that there is a need for a large multicenter prospective randomized controlled trial to be performed before a consensus can be reached on the influence of CAS techniques on blood loss during primary TKA.