The Effect of Systolic Blood Pressure on Cement Penetration Depth in Primary Total Knee Arthroplasty

Background: Cement Penetration Depth (CPD) into bone is an important factor for successful Total Knee Arthroplasties (TKA). Our study investigated the effect of Systolic Blood Pressure (SBP) on average tibial, femoral and total CPD in primary TKA.

Methods and Findings: In this retrospective cohort study, patients who had a primary TKA between November 2018 and February 2020 at four, academic medical centers were included. CPD was evaluated according to the Knee Society Radiographic Evaluation System on radiographs one month post-operatively. Two independent evaluators measured four zones of tibial penetration and three zones of femoral penetration and averaged their results. The measurements were combined to create an average tibial, average femoral and average total CPD. SBP was collected at the 3/4 time of surgery length- the estimated time of cementation.

1221 primary TKA cases were included in the study – 1128 in the tourniquet group and 93 in the tourniquet-less group. There were no significant differences between the age, sex, BMI, or LOS between the two cohorts. A multiple, multivariate analysis was performed. In the tourniquet-less group, SBP did not significantly affect average tibial CPD (p=0.98), average femoral CPD (p=0.45), or average total CPD (p=0.23). However, tourniquet use was found to significantly increase average femoral (p<0.001) and total penetration (p=0.001). 

Conclusion: SBP did not significantly affect tibial, femoral, or total CPD in patients undergoing tourniquet-less, primary TKA. However, the use of a tourniquet significantly aids in average femoral and total CPD. The clinical significance of this difference needs further investigation.