Abstract
Introduction
Patients undergoing total knee arthroplasty have expected blood loss during and after surgery. The current literature remains inconclusive in regards to which surgical instrumentation techniques in total knee arthroplasty are effective in minimising peri-operative blood loss. The primary objective of this retrospective review of a prospective randomized cohort study is to compare surgical and patient factors and their influence on blood loss and transfusions rates between one type of Patient Specific Instrumentation (PSI) (SignatureTM), Navigated Computer-Assisted Surgery (CAS) and Conventional Total Knee Arthroplasty (TKA) surgical techniques.
Method
128 matched patients (38 SignatureTM, 44 CAS, 46 Conventional surgeries) were compared. Pre-operative factors were analysed including; age, gender, Body Mass Index (BMI), pre-operative hemoglobin (g/L), International Normalized Ratio (INR), use of anticoagulants and co-morbid bleeding diathesis. Maximal hemoglobin drop were compared on Day 1 to 3, as well as, transfusion requirement. Peri-operative factors were collected including; surgical time, tourniquet time, drain output, insitu drain time, order of tibia or femoral cut and intra-operative loss from suction.
Results
No significant differences were found between the three groups on the pre-operative patient demographics examined. The mean Hb pre-operative was 140 for PSI, 135 for CAS and 139 for Conventional. The mean post-operative Hb was 111 for PSI, 104 for CAS and 107 for conventional. Thereby calculating that the mean percentage drop was 21%, 23% and 23% respectively. The difference between Pre-Op Hb and the lowest of the Post-Op Hb readings does not significantly differ between the three groups (p=0.39). A significant difference is seen between the three groups with respect to Day 1 Hb drop (p=0.05). In the study, 4 patients required transfusion due to either hemoglobin <80g/l or clinically symptomatic. The 4 patients were all from the Conventional TKR group.
Conclusion
Surgical technique does not appear to influence post-operative blood loss when comparing PSI, CAS and Conventional TKA. This is the first article to compare all three knee arthroplasty systems in a matched patient series. The surgeon's preference of drain use does not appear to influence post-operative blood loss.
