TOURNIQUET USE DOES NOT AFFECT BLEEDING AND SURGICAL TIME IN ROBOTIC-ASSISTED KNEE ARTHROPLASTY

ABSTRACT

Objective:

To compare bleeding and surgical time in patients undergoing Total Knee Arthroplasty (TKA) with robotic assistance with and without the use of a tourniquet.

Methods:

Retrospective study with analysis of medical records. Patients were divided into two groups: one group in which robotic-assisted TKA was performed using a tourniquet and the other without. The values of hemoglobin (Hb) and hematocrit (Ht) preoperative and 24 hours after surgery, the estimated blood loss, number of transfusions and surgical time were compared between the groups.

Results:

108 patients were included, with 59 in the group using a tourniquet and 49 without. There was no difference between the mean Hb and Ht values between the groups preoperatively (p = 0.287 and p = 0.508) and 24 hours (p = 0.252) after surgery. There was also no difference between the estimated blood loss in each group (p = 0.265). Surgical time was not different between groups (p = 0.179). There was no need for transfusions in any patient.

Conclusion:

Robotic-assisted TKA surgeries, whether performed with or without a tourniquet, showed no significant differences in the drop in Hb and Ht levels 24 hours after surgery, estimated blood loss, transfusions, and surgical time. Level of Evidence III; Retrospective cohort study.

INTRODUCTION

The use of robotic technology in surgery has proven effective in improving precision during soft tissue dissection, as well as contributing to enhancing the postoperative rehabilitation process in different medical fields. ¹ Robotic-Assisted Total Knee Arthroplasty (TKA) allows for better precision in bone cuts, leading to improved implant positioning and less soft tissue damage ² , factors that may be related to higher patient satisfaction and increased implant longevity. ³ Additionally, it could be associated to reduced blood loss ⁴ and decrease postoperative pain in patients ⁵ .

The use of a tourniquet in TKA procedures has become a topic of debate in the literature in recent years. ⁶ In conventional TKA, some studies have shown an increase in hidden intraoperative blood loss ⁷ , a higher incidence of infections ⁸ , and postoperative pain, in patients operated with a tourniquet compared to those where it was not used. ⁶ In robotic-assisted TKA, this divergence regarding the use of the tourniquet persists, and there are few comparative studies. Lai et al. ⁹ demonstrated greater hidden bleeding, more postoperative pain, and muscle injury in patients operated with a tourniquet during robotic-assisted arthroplasty and justified these findings by the longer intraoperative time related to the robotic assistance. However, a recent meta-analysis showed no significant difference in surgical time between conventional and robotic surgery ¹⁰ .

Given the ongoing controversy, this study aimed to compare patients undergoing robotic-assisted TKA with and without the use of a tourniquet. The focus was on analyzing whether there was a difference in blood loss 24 hour after surgery and in surgical time.

METHODS

The present study was conducted after approval by the Research Ethics Committee in accordance with resolution No. 466/2012 of the National Health Council and the Declaration of Helsinki with number CAAE: 71836523.2.0000.5696. A retrospective study was performed with the analysis of medical records of patients who underwent robotic-assisted TKA between October 2022 and June 2023. Patients with a diagnosis of rheumatoid arthritis, patients with coagulation disorders, or the useof anticoagulants up to 7 days before surgery were not included. Patients were divided into two groups (one in which the surgery was performed using a tourniquet and another without) randomly by draw and operated by four surgeons with more than 10 years of experience in knee arthroplasties from the same team and following the same protocol. Preoperative Hb and Ht values, as well as those 24 hours after surgical procedure, the estimated blood loss calculation, and the time required to perform the procedure, were recorded and compared between the groups.

All patients operated on during the period were included and had blood samples collected via peripheral puncture preoperatively and 24 hours after surgery. Additionally, the surgical time for each procedure was recorded by the nursing and anesthesia team. All patients underwent spinal anesthesia, were operated on via a medial parapatellar approach, maintaining ischemia from the beginning of the skin incision until the final dressing in the cases of tourniquet use. The implants used were always cemented, without patellar replacement, and using the same instrumentation with robotic arm assistance during surgery (ROSA® Knee System, Zimmer, Warsaw, IN, USA). No suction drains were used in any case. All patients received 1g of intravenous tranexamic acid at anesthetic induction. Mechanical thromboembolic prophylaxis was implementedusingelastic stockings and an intermittent pneumatic compression pump for the first 24 hours after the procedure. Pharmacological prophylaxis consisted of 10mg of oral rivaroxaban administered 6 hours after the procedure, followed by a dose every 24 hours during hospitalization and continuing until the tenth postoperative day for all patients.

The obtained results were statistically analyzed by comparing the two groups. The following parameters underwent statistical analysis: Hb and Ht values before and 24 hours after surgery, decrease in Hb and Ht values 24 hours after the procedure, calculation of estimated blood loss by Body Mass Index (BMI) (using estimates from Nadler et al. ¹¹ and equations described by Lisander et al. ¹² ), surgery time, sex, age, BMI, and number of transfusions. The criterion for indicating transfusion was Hb less than 7g/dl associated with clinical symptoms such as hemodynamic instability, oliguria, decreased level of consciousness, or poor general condition.

The categorical variable was presented by frequency and percentage. Quantitative variables were analyzed for normality using the Shapiro-Wilk test. The values are described as mean ± standard deviation (SD). Pearson's chi-square test was used to assess the statistical significance of qualitative variables, and the t-test was used for numerical data according to normality. The results were analyzed using the Statistical Package for the Social Sciences (SPSS) - 23.0 (IBM Corp., Armonk, NY, USA), with a confidence level of 5% established for all tests applied.

RESULTS

One hundred and eight patients were included in the study. The tourniquet group consisted of 59 patients, whilethe non-tourniquet group had 49 patients (Figure 1). The mean age inthe tourniquet group was 68.1 years, with a standard deviation of 7.6 years, while in the non-tourniquet group it was 67.4 years, with a standard deviation of 9.5 years. There was no statistically significant difference in age between the groups. There was also no statistically significant difference related to gender distribution, BMI, preoperative Hb and Ht between groups (Table 1).

Figure 1. Flowchart of patients evaluated after robotic TKA.

Total Knee Arthroplasty (TKA).

Table 1. Demographic characteristics of the study population.

Variable	Tourniquet group (n=59)	Non-tourniquet group (n=49)	P*
Age (years) (mean±SD)	68.1 ± 7.6	67.4 ± 9.5	0.648
Male, n (%)	24 (40.7)	29 (59.2)	0.056
BMI (mean±SD)	30.1 ± 4.4	30.4 ± 4.9	0.712
Hemoglobin, g/dl (mean±SD)	13.97 ± 1.30	14.25 ± 1.48	0.287
Hematocrit, % (mean±SD)	41.60 ± 3.86	42.12 ± 4.41	0.508

Standard deviation (SD); Body mass index (BMI).

A shorter mean operative time was observed in the tourniquet group (108.7 ± 20.4 min) compared to the non-tourniquet group (114.4 ± 23.2 min), but without a significant statistical difference (Table 2).

Table 2. Comparison between the groups regarding surgical time and bleeding.

Variable	Tourniquet group (n=59)	Non-tourniquet group(n=49)	P*
Surgical time, min (mean±SD)	108.7 ± 20.4	114.4 ± 23.2	0.179
Hemoglobin reduction (g/dL)	2.28 ± 0.92	2.54 ± 1.36	0.252
Estimated blood loss (ml)	765.4 ± 290.6	842.4 ± 421.4	0.265
Transfusion (n)	0	0	N/A

Standard deviation (SD).

Regarding bleeding evaluation, the mean reduction in Hb was slightly lower in the tourniquet group (2.28 ± 0.92 g/dL) compared to the non-tourniquet group (2.54 ± 1.36 g/dL), but it was also not statistically significant (Table 2). Estimated blood loss was lower in the tourniquet group (765.4 ± 290.6 mL) compared to the non-tourniquet group (842.4 ± 421.4 mL), however, this difference was also not statistically significant (p=0.265). No patient required a blood transfusion (Table 2).

DICUSSION

This study suggests that the use of a tourniquet in robotic assisted TKA does not lead to reduce bleeding 24 hours after surgery (p=0.265), nor does it reduce operative time. Lai et al. ⁹ conducted a randomized, controlled, double-blind trial comparing similar outcomes, including bleeding and operative time, in patients undergoing robotic-assisted TKA, but with only 14 patients in each group. Many studies compare robotic TKA to conventional techniques but do not compare the use or not of the tourniquet ^13,14,15 . We have shown that the use of a tourniquet in robotic-assisted TKA resulted in a slightly lower mean blood loss but not significantly different in volume compared to the non-ischemic technique (765.4 ml vs. 842.4 ml). Similarly, the study conducted by Lai et al. ⁹ showed that although the tourniquet appeared to reduce intraoperative blood loss, it did not reduce hidden blood loss. Another study evaluating conventional TKA also found similar results regarding bleeding with tourniquet use. ¹⁶ Robotic-assisted surgery already indicates better outcomes in terms of blood loss compared to conventional techniques when both are performed with a tourniquet. ¹⁷

Another data point that did not show a significant difference between the groups was surgical time. This finding differs from recent meta-analyses conducted with data from surgeries without robotic assistance, which indicate the tourniquet as a factor reducing surgical time. ^6,7 We understand that including a larger number of patients in the study might possibly show some difference in this variable. The surgeons experience in operating without a tourniquet couldalready narrowed the surgical time even using robotic arm assistance.

This study has limitations. First, because it is a retrospective study. A prospective randomized study with the same number of patients might yield different results. Second, it uses data from a single center, which may limit the number of patients studied, although it reduces the bias of comparing different surgeons with different practices. Third, we did not have evaluations beyond 24 hours post-surgery because many patients were discharged before 48 hours after surgery, making it difficult to collect new bloodtests.

At the end of the study, it was observed that robotic-assisted surgery can be performed without the use of a tourniquet without compromising surgical time and without causing significant bleeding. This may help avoid the complications already described related to tourniquet use. ^6,18

CONCLUSION

Robotic-assisted TKA surgeries performed with and without the use of a tourniquet showed no significant difference in the decrease in Hb and Ht levels 24 hours after surgery, estimated blood loss, transfusions, and surgical time.

DATA AVAILABILITY DECLARATION

The contents underlying the research are available in the manuscript.