Abstract
Introduction:
Efforts continue to reduce blood loss in total knee arthroplasty (TKA). Computer assisted surgery (CAS) has been shown to reduce outliers in component position and improve functional outcomes in TKA, yet few studies have reported specifically on blood loss. The primary study objective was to determine whether a modern abbreviated CAS protocol would reduce blood loss in TKA compared to conventional instrumentation. A secondary objective was to assess the effect of CAS on cost and surgical efficiency.
Methods:
A retrospective cohort study of 100 consecutive patients was performed comparing an abbreviated and modern CAS protocol versus conventional IM instrumentation. All TKAs utilized an identical surgical technique without any hemostatic agent. Blood loss was determined using drain output, change in hemoglobin, and calculated blood loss. Tourniquet times were recorded as an indicator of procedural efficiency. A cost analysis compared the CAS protocol to the cost associated with tranexamic acid (TXA) to reduce blood loss and long-leg alignment radiographs to optimize component position.
Results:
Height, weight, BMI, and preoperative hemoglobin were similar between groups. The CAS group demonstrated a decrease in average hourly drain output (CAS 33.8 ml; conventional 40.5 ml; p = 0.024), decreased change in hemoglobin (CAS 2.2; conventional 3.1; p < 0.001), and estimated total blood loss (CAS 925 ml; conventional 1327 ml; p < 0.001) compared to conventional instrumentation. No patients in either group required a blood transfusion. In non-teaching cases, there was a mean increase of 5 minutes surgical time in the CAS group. Cost-analysis demonstrated CAS was less expensive than using TXA and long-leg alignment radiographs, with a savings of $564 for 200 TKAs annually and $284 for 100 TKAs annually.
Conclusion:
AbbreviatedCAS is effective in reducing blood loss in TKA comparable to TXA, likely due to avoidance of the femoral IM canal, with minimal effect on surgical efficiency. Along with proven advantages of accurate component placement and improved functional outcome after TKA, the additional blood conservation supports CAS providing value in healthcare and obviates the need for advanced preoperative imaging and TXA, and can be used in patients regardless of cardiac or thromboembolic risk.
