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Are tourniquets indicated in total knee arthroplasty in the era of tranexamic acid: A meta-analysis and systematic review
, Rajkishen Narayananb, Kevin K. Chenb, Daniel Hameedd, Jeremy Dubind, Ameer Elbulukb, James E. Fengb, Richard Iorioc, Ran Schwarzkopfb,
⁎Corresponding author: Ran Schwarzkopf. Ran.schwarzkopf@nyumc.org
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Received: ,
Accepted: ,
This article was originally published by Reed Elsevier India Pvt. Ltd. and was migrated to Scientific Scholar after the change of Publisher.
Abstract
Abstract
There is conflicting evidence in the literature regarding the clinical utility of tourniquets in total knee arthroplasty (TKA), specifically in regards to perioperative blood loss. In this meta-analysis and systematic review, we aim to evaluate the clinical advantages and disadvantages associated with tourniquet use in the setting of TKA.
A systematic review was conducted through April 2017 using keywords: “tourniquet” and “total knee arthroplasty” or “total knee replacement”. Perioperative variables including TXA use, blood loss, incidence of venous thromboembolism (VTE), and wound complications were either extracted from the studies or corresponding authors were contacted. A sub-analysis was conducted to evaluate the effects of TXA on intraoperative and total blood loss (TBL), and VTE incidence.
After review of 558 articles, 19 studies reporting outcomes in 1094 patients were analyzed. Intraoperative blood loss was significantly lower in the tourniquet cohorts compared to non-tourniquet (p < 0.01). TBL was reduced in tourniquet groups but not significantly (p = 0.08). In contrast, calculated blood loss was greater in tourniquet groups, but this difference was not significant (p = 0.43). There was a greater likelihood for wound complications and VTE among tourniquet assisted TKA, albeit only significant for the former (p = 0.01). TXA sub-analysis demonstrated intraoperative blood loss was significantly reduced with tourniquet use regardless of TXA implementation (p < 0.01). In studies without TXA, tourniquet patients were at greater risk of developing VTE (p = 0.08). These risks decreased with TXA administration.
This meta-analysis demonstrates that tourniquets prevent intraoperative blood loss, yet within the postoperative period, there is no significant difference in TBL between tourniquet and non-tourniquet assisted TKA.
Level II; Systematic Review and Meta-Analysis.
Keywords
Tourniquet
Total knee arthroplasty
Meta-analysis
Systematic review
Blood loss
Tranexamic acid
1 Introduction
Tourniquets have a long history, originating in the fourth century BC with their use by Greek and Roman Armies to prevent blood loss during amputations. French Surgeon Jean Louis Petit introduced the modern tourniquet in 1718, consisting of a belt and screw-like rod. Since the emergence of total knee arthroplasties (TKAs) in the 1960s, tourniquets have been employed to manage bleeding during surgery, improving visibility and facilitating cement interdigitation between bone and implant.1,2
Despite their benefits, tourniquet-assisted TKA comes with drawbacks, including increased risks of thromboembolic events, thigh pain, nerve damage, ischemia, soft tissue injury, and impaired wound healing.3–6 Additionally, tourniquet use may extend postoperative recovery due to reduced muscle strength, limited knee range of motion, and heightened pain for up to a year afterward. Although tourniquet-assisted TKA can minimize intraoperative blood loss, studies have shown no significant reduction in total blood loss post-surgery.7–12
Advancements in surgical techniques and prosthesis design over the past six decades have improved outcomes and implant longevity in TKA. Notably, the widespread adoption of tranexamic acid (TXA) in total joint arthroplasty (TJA) has significantly reduced postoperative blood loss. However, TXA use carries a slight risk of thromboembolic events and anaphylaxis, though such complications are rare.13–15
As the number of TKAs is expected to rise, it's crucial for orthopedic surgeons and patients to understand the pros and cons of tourniquet-assisted TKA fully. While several meta-analyses and systematic reviews have explored perioperative outcomes associated with tourniquet use in TKA, no studies have comprehensively compared the prevalence of thromboembolic events and wound complications in tourniquet-assisted TKA with and without TXA.16 This study aims to address this gap through meta-analysis, focusing on complications associated with both tourniquet-assisted and tourniquet-free TKA. Additionally, it will reevaluate perioperative outcomes in studies using TXA in both types of TKA. We hypothesize that while tourniquet-assisted TKA may reduce intraoperative blood loss, it will also be associated with higher rates of VTEs and wound complications. Furthermore, our sub-analysis is expected to show that patients receiving TXA will experience comparable blood loss to those undergoing tourniquet-assisted TKA, but with fewer complications.
2 Materials and methods
2.1 Search strategy
The present study was conducted from March 2017 to June 2017. This study was performed in accordance with both the Preferred Reporting Items for Systematic and Meta-Analysis Statement and the Cochrane Handbook for systematic reviews and meta-analyses (Fig. 1). An initial search of the Cochrane Library, PubMed, and Embase databases using the following keywords and their combinations: tourniquet, arthroplasty, replacement, knee, and tranexamic acid. Articles published between 2000 and 2017 were included in our literature search and were limited to English studies in human subjects. In addition, the bibliographies of retrieved articles and other relevant papers were also screened manually for eligible studies.
2.2 Inclusion criteria
All full-text randomized controlled trials (RCTs) comparatively evaluating the role of tourniquet and non-tourniquet assisted TKA, regardless of TXA usage were considered for inclusion. As endorsed by the Cochrane Collaboration, PICOS (Population, Intervention, Comparator, Outcomes, Study Design) criteria was used to systematically conduct the literature review.17Population: patients undergoing primary TKA. Intervention: tourniquet use in TKA. Comparator: tourniquet-assisted TKA versus non-tourniquet assisted TKA. Outcomes: operative time, blood loss, allogenic transfusion figures, thromboembolic events, and wound complications. Study Design: only level one RCTs were included, all other studies were excluded. Additionally, studies that compared early and late release of tourniquet were excluded, as they lacked a non-tourniquet cohort. Lastly, another study that had been included in a prior meta-analyses was excluded because all its participants were all women.18
2.3 Study selection and data collection
A standard data extraction form was designed to retrieve relevant data points from the eligible studies. Two reviewers independently screened all titles and abstracts identified by the initial search to assess their eligibility for inclusion. Full-manuscript screening was then conducted as a final evaluation of a study's eligibility. After all eligible manuscripts had been evaluated for inclusion, data extraction was conducted by the 2 reviewers using a predefined data collection sheet presented in (Table 1). The data collection form was designed prior to data retrieval and was circulated amongst all the authors until consensus had been reached. In-regards to TXA status, all studies published prior to 2008, were assumed to be TXA-free. For studies published in 2008 and beyond, corresponding authors were contacted to determine TXA status Any discrepancies with abstracted data was resolved by a third independent reviewer.
| # | Study | Year | Sample Size | Age (yrs.) | Gender (M/F) | BMI | ||||
| Study Year | Tourniquet | Non-tourniquet | Tourniquet | Non-tourniquet | Tourniquet | Non-tourniquet | Tourniquet | Non-tourniquet | ||
| 1 | Mori et al. | 2016 | 52 | 51 | 72.8 ± 7.3 | 74.6 ± 7.6 | 6/45 | 9/43 | 27.7 ± 3.4 | 29.2 ± 3.9 |
| 2 | Pfitzner et al. | 2016 | 45 | 45 | 69.3 | 70.5 | 21/24 | 1/34 | 27.8 | 26.0 |
| 3 | Dennis et al. | 2015 | 46 | 10 | 62.0 ± 6.0 | 16/12 | 29.0 ± 4.0 | |||
| 4 | Harsten et al. | 2014 | 32 | 32 | 68 ± 8.0 | 66.0 ± 8.0 | 77/15 | 18/14 | 28.4 | 27.4 |
| 5 | Liu et al. | 2014 | 10 | 10 | 67.0 | 70.0 | 7/3 | 9/1 | n/a | n/a |
| 6 | Tai et al. | 2012 | 36 | 36 | 72.1 ± 6.9 | 71.5 ± 6.8 | 9/27 | 8/28 | 28.6 ± 4.5 | 27.9 ± 4.2 |
| 7 | Ledin et al. | 2012 | 23 | 25 | 70.0 ± 8.0 | 71.0 ± 6.0 | 10/15 | 9/14 | 29 ± 4.8 | 28 ± 4.8 |
| 8 | Ejaz Nielsen et al. | 2014 | 35 | 35 | 68.0 ± 8.4 | 68 ± 7.8 | 18/15 | 17/14 | 25 ± 2.0 | 25 ± 2.5 |
| 9 | Zhang et al. | 2010 | 30 | 30 | 72.0 ± 6.0 | 71.0 ± 6.0 | 8/22 | 11/19 | 25.0 ± 4.0 | 26.0 ± 4.0 |
| 10 | Yavarika et al. | 2010 | 22 | 29 | 66 | 68 | 6/16 | 7/22 | n/a | n/a |
| 11 | Li et al. | 2009 | 40 | 40 | 71.0 ± 6.0 | 70.0 ± 7.0 | 11/29 | 13/27 | 27.3 ± 6.3 | 26.8 ± 5.1 |
| 12 | Kageyama et al. | 2007 | 11 | 11 | 76.0 ± 3.0 | 73.0 ± 4.0 | 2/9 | 2/9 | 24.67 | 26.58 |
| 13 | Matziolis et al. | 2005 | 10 | 10 | 72.4 | 76.6 | 2/8 | 3/7 | 28.3 | 29.5 |
| 14 | Vandenbussche et al. | 2002 | 40 | 40 | 72.5 | 68.5 | 9/31 | 16/24 | n/a | n/a |
| 15 | Kato et al. | 2002 | 24 | 22 | 65.0 ± 10.0 | 63.0 ± 8.0 | 1/23 | 2/20 | n/a | n/a |
| 16 | Tetro et al. | 2001 | 30 | 33 | 69.8 ± 6.7 | 69.8 ± 9.0 | 15/18 | 11/19 | n/a | n/a |
| 17 | Aglietti et al. | 2000 | 10 | 10 | 70.0 ± 8.0 | 68.0 ± 4.5 | 3/7 | 4/6 | 27.9 | 27.3 |
| 18 | Wakankar et al. | 1999 | 40 | 37 | 72.5 | 71.8 | 11/26 | 14/26 | n/a | n/a |
| 19 | Abdel-Salam et al. | 1995 | 40 | 40 | 72 | 74 | 17/23 | 15/25 | n/a | n/a |
2.4 Outcomes measures
The primary outcome measures evaluated in our meta-analysis included the average reported operative time, blood loss, as well as the prevalence of allogenic transfusions, thromboembolic events, and wound complications among patients who underwent tourniquet-assisted and tourniquet-free TKA. Secondary analysis was conducted on all studies depending on TXA status. Outcomes for the aforementioned variables were reported in patient cohorts who underwent tourniquet-assisted TKA with TXA and tourniquet-free TKA with TXA.
2.5 Subgroup analysis
We utilized Review Manager (RevMan), version 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, 2009, Copenhagen, Denmark), for statistical analysis. Statistical heterogeneity among the studies was assessed using the I2 statistic, with significance set at a c2 of <0.05. For heterogeneity where I2>50 %, a random-effects model was employed for meta-analysis. Conversely, when I2<50 % and p < 0.1, a fixed-effects model was utilized. Subgroup analysis was conducted to explore heterogeneity sources. In cases of heterogeneity, wider confidence intervals (CIs) were observed with the random-effects model, ensuring conservative claims of statistical significance. Risk ratios (RRs) were reported for dichotomous variables like wound complications, while mean differences and standard deviations (SDs) were used for continuous variables. All analyses were conducted via the Mantel-Haenszel random-effects model. Meta-analysis results were presented using forest plots, depicting a 95 % confidence interval (CI) for each study alongside a cumulative weighted mean effect. Inconsistently reported variables were thoroughly examined in the systematic review section. Statistical significance was set at a p-value <0.05.
3 Results
3.1 Study characteristics
Our literature search revealed 558 articles of which 43 were identified as duplicates. After reviewing the titles and abstracts of all studies, it was determined that 19 studies were eligible for final analysis, all of them RCTs (Fig. 1). Reasons for exclusion included irrelevant outcome measures including: cementation, wound oxygenation/hypoxia, and biomarkers of protein degradation, and incomparable study endpoints. In total, 19 selected studies incorporated 1071 knees, of which 535 and 536 underwent tourniquet-assisted and tourniquet-free TKA. A summary of the extracted variables is presented in Table 1.
3.2 Blood loss
Intraoperative blood loss (milliliters), defined as blood from sponges and swabs as well as suction and irrigation volumes obtained during surgery were reported in 9 studies. Fig. 2A illustrates tourniquet use significantly reduced intraoperative blood loss (mean difference [MD]: 190.17, 95 % CI -201.30, −179.03; p < 0.01). Total blood loss was estimated by adding intraoperative blood loss to postoperative blood collected in drains, which was measured in 7 studies (Fig. 2B). Most studies reported reduced total blood loss associated with tourniquet use, albeit not statically significant (MD: 134.57; 95 % CI -283.74,14.60; p = 0.08). Calculated blood loss (milliliters), which reflects actual blood loss, was determined by accounting for the decrease in hemoglobin (Tetro 2001) or by hematocrit (Li 2009 and Tai 2012). Two of three studies reported higher calculated blood loss with tourniquet use but there was no significant difference reported between the two cohorts (MD: 103.21; 95 % CI -152.52, 358.94; p = 0.43; Fig. 2C).
3.3 Transfusions
Six studies reported the number of patients requiring transfusions in their respective cohorts. Most studies reported increased likelihood of transfusion with tourniquet use, however this association was not significant (OR: 1.73; 95 % CI 0.83, 3.59; p = 0.14; Fig. 3A). Volume of blood transfused was reported in 2 studies, both of which reported higher volume of transfusion in tourniquet-free group, although this difference was not significant (MD: 182.52; 95 % CI -521.60, 156.55; p = 0.29; Fig. 3B).
3.4 Venous thromboembolic events and wound complications
Venous thromboembolic events can be a devastating complication following TKA. Analysis of 9 studies that reported VTE outcomes demonstrated a non-significant increased risk of VTEs with tourniquet use (OR: 2.24; 95 % CI 0.78, 6.42; p = 0.13; Fig. 4A). Seven studies reported wound related complications following TKA and there was a significantly increased risk associated with tourniquet use (OR: 3.48; 95 % CI 1.29, 9.37; p = 0.01; Fig. 4B).
3.5 Operative time
Fourteen studies reported operative times (in minutes), revealing no significant difference between tourniquet and tourniquet-free cohorts (MD: 4.76; 95 % CI -10.05; 0.54; p = 0.08) (Fig. 5a).
3.6 Tranexamic Acid Sub-analysis
After contacting all corresponding authors for studies published after 2009, four RCTs were identified as using TXA. The effect of tourniquet use was separately assessed in patient cohorts depending on their TXA status. Our sub-analysis demonstrated that intraoperative blood loss was significantly reduced with tourniquet use regardless of TXA status (Fig. 6A and B). Similarly, total blood loss was also reduced with the use of a tourniquet regardless of TXA status (Fig. 6C and D). A comparison of VTE incidence between TXA and non-TXA studies was performed (Fig. 7A and B). Three TXA studies indicated no difference in VTE risk among tourniquet and tourniquet-free cohorts (OR 0.95; 95 % CI 0.08, 10.41; p = 0.95; Fig. 7A). Six non-TXA studies demonstrated a higher risk for VTEs with tourniquet-assisted TKA, although trending towards significance (OR: 3.68; 95 % CI 0.86, 15.76; p = 0.08; Fig. 7B). Finally, regardless of TXA use, there was no significant difference in operative times between tourniquet and non-tourniquet cohorts (Fig. 5B and C).
4 Discussion
4.1 Intra-operative blood loss
With the availability of newer methods to minimize blood loss during TKA, orthopedic surgeons must now reevaluate the utility of tourniquets. Numerous studies have demonstrated that tourniquets are associated with reduced intraoperative blood loss. With less bleeding, surgeons should have a better visual field allowing the surgeon to work more efficiently. In the studies evaluating intraoperative blood loss, there was a significant reduction in blood loss when tourniquets were used. This is consistent with prior meta-analyses.2,3,10–12,19–21 Interestingly, operative time was not significantly reduced with use of a tourniquet. This may be due to the advent of TXA use in newer RCTs which may aid in achieving a more “bloodless” surgical field.
4.2 Post-operative blood loss
We also included total measurable blood loss and calculated blood loss in our meta-analysis to provide a more complete picture of blood loss within the perioperative window. Prior studies have reported conflicting results on how tourniquets affect TBL. Measurable total blood loss is calculated by adding intraoperative and postoperative blood loss. Studies that recorded postoperative blood loss included sponge weight and postoperative drainage fluid.7,22–27 Calculated blood loss, which is always regarded as true total blood loss, was measured by hemoglobin (Hb) and hematocrit (Hct) levels before and after surgery. Our analysis showed that measurable total blood loss and calculated blood loss were not significantly different in tourniquet and non-tourniquet groups. While intraoperative blood loss was clearly lower in tourniquet-assisted TKA, this postoperative observation may be explained by continued blood loss following surgery. It has been suggested that tourniquet-induced ischemia results in sustained local reactive hyperemia lasting many hours after tourniquet removal. Some studies have attempted to take into account this hidden blood loss, which is calculated by subtracting intraoperative blood loss and postoperative wound blood loss from calculated blood loss.28 While we did not carry out this calculation due to differences in reporting of blood loss outcomes across the included studies, it may serve as an explanation for the difference in findings between intraoperative versus total and calculated blood loss.
4.3 Transfusions
In order to understand the clinical significance of this blood loss, we performed an analysis of transfusion rates following TKA. We showed that transfusion rates were non-significantly higher with tourniquet use which is in agreement with some prior on this outcome.10–12 Transfusion volume has not previously been assessed in relation to tourniquet use. It was interesting to observe that tourniquets lowered the required transfusion volume, although not significantly. Our study confirms the findings of two prior meta-analyses reporting that tourniquets do not make a significant difference in transfusion requirements.
4.4 Venous thromboembolic events
Venous thromboembolic events (VTEs) are well recognized risk factors of TKA and the literature does show a consensus that tourniquets are associated with increased risk of VTEs, albeit not statistically significant. Our meta-analysis of VTE incidence across the included studies confirms these prior findings. The clinical significance of the VTE data is still unclear as their does appear to be some level of increased risk when using a tourniquet across multiple studies.
4.5 wound complications
Another complication that has been associated with tourniquet use is wound complications, such as infection, dehiscence, and drainage. Unlike VTE incidence, prior literature and our own meta-analysis demonstrates a consensus that the absence of a tourniquet is associated with significantly fewer wound complications. Ischemia and reperfusion to the extremity may induce the release of inflammatory cytokines causing oxidative stress to the tissue, increasing susceptibility to infection. Jawhar et al. performed 2 RCTs to investigate tourniquet induced reperfusion injuries following TKA and reported that an inflammatory cascade ensuing following tourniquet removal. Their results suggest an increase in protein degradation following tourniquet-induced ischemia which may explain some of the wound complication data in our study as well as prior analyses.29
4.6 Other parameters
As Alcilek et al. pointed out in their 2012 meta-analysis, the main reason for using a tourniquet in TKA is to clear the field of interfering blood, allowing for better cement penetration.2 At the time of their study, no data on implant survival or cementation was available. Since then, multiple RCTs7,30–32 have been conducted that assessed cementation. The results have been mixed, with two studies finding no difference in cementation outcomes in tourniquet vs non-tourniquet TKA,33,34 while one study did find greater cement mantle thickness associated with tourniquet use.35 The challenge with these studies is that they measured cementation in slightly different methods (lateral tibial plateau cement penetration, tibial cumulated cement mantle thickness, or radioisometric analysis (RSA) of maximal total point motion (MTPM).
4.7 TXA vs Non-TXA subgroup analysis
Studies with TXA had slightly more equal operative times between tourniquet and non-tourniquet groups compared to studies without TXA. While this relationship was not significant, it suggests a potential impact that TXA may have on reducing operative times in non-tourniquet TKA, possibly by making the operative field more manageable with less bleeding. This is further corroborated by our finding that TXA studies had a greater degree of intra-operative blood loss reduction compared to non-TXA studies (mean difference in IBL: 108 ml and 150 ml, respectively).
Addition of TXA also appears to have an effect on post-operative blood loss, as TXA studies demonstrated a significant reduction in TBL associated with tourniquet use (a relationship which was non-significant in studies without TXA).
In our examination of VTE incidence, TXA studies demonstrated a non-significant reduction in VTE risk compared to non-TXA studies. This finding could be multi-factorial, as many of the TXA studies were published more recently and improved thromboprophylaxis regimens may in part contribute to these findings. Several studies and meta-analyses have been conducted to verify that there is no difference in incidence of VTE in patients undergoing TKA and THA with and without TXA.36–39
5 Limitations
There are some limitations in our meta-analysis that should be addressed. Our literature search was exclusive to papers published in English, which would exclude some potential RCTs. Some included studies had relatively small sample sizes, with 10 patients randomized to each arm. The power of these studies is reduced compared to other larger samples, which makes it difficult to draw strong conclusions from them. Our reviewers adhered to very strict inclusion criteria, excluding studies that did not report randomization, blinding, and participant selection methodology. Studies with potentially meaningful outcomes may have been excluded inadvertently due to such reporting deficiencies. Lastly, transfusion protocols, surgical techniques, anesthesia modalities, drain use, tourniquet release times, prosthesis types, thromboprophylaxis interventions, and tourniquet peak pressures varied by study and could not be assessed in a meaningful way via subgroup analysis.8,26 Despite these limitations, our study clearly demonstrates that tourniquet-assisted TKA is associated with substantial perioperative risks and few advantages. Thus, future RCTs should evaluate the risks and benefits associated with tourniquet and tourniquet-free TKA to better understand and quantify the role of tourniquets within TKA.
6 Conclusion
Although tourniquet use results in less intraoperative bleeding, our results indicate that this total perioperative blood loss is similar amongst tourniquet and non-tourniquet assisted TKA. However, tourniquet-assisted TKA is associated with an increased complication profile with no significant reduction in total perioperative blood loss when compared to non-tourniquet assisted TKA. The relatively high complication profile associated with tourniquet use demonstrates that TXA alone may be sufficient for primary TKA. Prior to widespread implementation of tourniquet-free TKAs, RCTs assessing the clinical efficacy of this procedure are warranted.
Funding
None.
Patient consent
No patient consent needed due to retrospective nature and public database.
Ethical approval
IRB exemption due to retrospective nature and public database Authors’ contribution.
Authors’ contribution
JD- Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
DH- Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
AA-Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
RN-Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
KC- Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing. MM- Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
AE- Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
JF-Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
RI-Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
RS-Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing.
Use of AI tool
No use of AI tool.
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