Safety and feasibility evaluation of tourniquets for total knee replacement (SAFE-TKR): study protocol

Early patient-reported outcomes from primary hip and knee arthroplasty have improved over the past seven years : an analysis of the NHS PROMs dataset

AIMS

Routinely collected patient-reported outcome measures (PROMs) have been useful to quantify and quality-assess provision of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in the UK for the past decade. This study aimed to explore whether the outcome following primary THA and TKA had improved over the past seven years.

METHODS

Secondary data analysis of 277,430 primary THAs and 308,007 primary TKAs from the NHS PROMs programme was undertaken. Outcome measures were: postoperative Oxford Hip/Knee Score (OHS/OKS); proportion of patients achieving a clinically important improvement in joint function (responders); quality of life; patient satisfaction; perceived success; and complication rates. Outcome measures were compared based on year of surgery using multiple linear and logistic regression models.

RESULTS

For primary THA, multiple linear regression modelling found that more recent year of surgery was associated with higher postoperative OHS (unstandardized coefficient (B) 0.15 points (95% confidence interval (CI) 0.14 to 0.17); p < 0.001) and higher EuroQol five-dimension index (EQ-5D) utility (B 0.002 (95% CI 0.001 to 0.002); p < 0.001). The odds of being a responder (odds ratio (OR) 1.02 (95% CI 1.02 to 1.03); p < 0.001) and patient satisfaction (OR 1.02 (95% CI 1.01 to 1.03); p < 0.001) increased with year of surgery, while the odds of any complication reduced (OR 0.97 (95% CI 0.97 to 0.98); p < 0.001). No trend was found for perceived success (p = 0.555). For primary TKA, multiple linear regression modelling found that more recent year of surgery was associated with higher postoperative OKS (B 0.21 points (95% CI 0.19 to 0.22); p < 0.001) and higher EQ-5D utility (B 0.002 (95% CI 0.002 to 0.003); p < 0.001). The odds of being a responder (OR 1.04 (95% CI 1.03 to 1.04); p < 0.001), perceived success (OR 1.02 (95% CI 1.01 to 1.02); p < 0.001), and patient satisfaction (OR 1.02 (95% CI 1.01 to 1.02); p < 0.001) all increased with year of surgery, while the odds of any complication reduced (OR 0.97 (95% CI 0.97 to 0.97); p < 0.001).

CONCLUSION

Nearly all patient-reported outcomes following primary THA/TKA improved by a small amount over the past seven years. Due to the high proportion of patients achieving good outcomes, PROMs following THA and TKA may need to focus on better discrimination of patients achieving high scores to be able to continue to measure improvement in outcomes. Cite this article: Bone Joint J 2022;104-B(6):687-695.

Effect of tourniquet use on the risk of revision in total knee replacement surgery: an analysis of the National Joint Registry Data Set

OBJECTIVE

Tourniquet use in total knee replacement (TKR) is believed to improve the bone-cement interface by reducing bleeding, potentially prolonging implant survival. This study aimed to compare the risk of revision for primary cemented TKR performed with or without a tourniquet.

DESIGN

We analysed data from the National Joint Registry (NJR) for all primary cemented TKRs performed in England and Wales between April 2003 and December 2003. Kaplan-Meier plots and Cox regression were used to assess the influence of tourniquet use, age at time of surgery, sex and American Society of Anaesthesiologists (ASA) classification on risk of revision for all-causes.

RESULTS

Data were available for 16 974 cases of primary cemented TKR, of which 16 132 had surgery with a tourniquet and 842 had surgery without a tourniquet. At 10 years, 3.8% had undergone revision (95% CI 2.6% to 5.5%) in the no-tourniquet group and 3.1% in the tourniquet group (95% CI 2.8% to 3.4%). After adjusting for age at primary surgery, gender and primary ASA score, the HR for all-cause revision for cemented TKR without a tourniquet was 0.82 (95% CI 0.57 to 1.18).

CONCLUSIONS

We did not find evidence that using a tourniquet for primary cemented TKR offers a clinically important or statistically significant reduction in the risk of all-cause revision up to 13 years after surgery. Surgeons should consider this evidence when deciding whether to use a tourniquet for cemented TKR.

Tourniquet use in total knee replacement surgery: a feasibility study and pilot randomised controlled trial (SAFE-TKR study)

INTRODUCTION

Tourniquets are routinely used during total knee replacement (TKR) surgery. They could increase the risk of thromboembolic events including cerebral emboli, cognitive decline, pain and other adverse events (AEs). A randomised controlled trial to assess whether tourniquet use might safely be avoided is therefore warranted but it is unclear whether such a trial would be feasible.

METHODS

In a single-site feasibility study and pilot randomised controlled trial, adults having a TKR were randomised to surgery with an inflated tourniquet versus a non-inflated tourniquet. Participants underwent brain MRI preoperatively and within 2 days postoperatively. We assessed cognition using the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA) and Oxford Cognitive Screen (OCS) and thigh pain using a Visual Analogue Scale at baseline and days 1 and 2, and 1 week postsurgery. AEs related to surgery were recorded up to 12 months.

RESULTS

We randomised 53 participants (27 tourniquet inflated and 26 tourniquet not inflated). Fifty-one participants received care per-protocol (96%) and 48 (91%) were followed up at 12 months. One new ischaemic brain lesion was detected. Of the cognitive tests, MoCA was easy to summarise, sensitive to change with lower ceiling effects compared with OCS and MMSE. There was a trend towards more thigh pain (mean 49.6 SD 30.4 vs 36.2 SD 28 at day 1) and more AEs related to surgery (21 vs 9) in participants with an inflated tourniquet compared with those with a tourniquet not inflated.

CONCLUSION

A full trial is feasible, but using MRI as a primary outcome is unlikely to be appropriate or feasible. Suitable primary outcomes would be cognition measured using MoCA, pain and AEs, all of which warrant investigation in a large multicentre trial.

TRIAL REGISTRATION NUMBER

ISRCTN20873088.

Tourniquet use for knee replacement surgery

BACKGROUND

Many surgeons prefer to perform total knee replacement surgery with the aid of a tourniquet. A tourniquet is an occlusive device that restricts distal blood flow to help create a bloodless field during the procedure. A tourniquet may be associated with increased risk of pain and complications.

OBJECTIVES

To determine the benefits and harms of tourniquet use in knee replacement surgery.

SEARCH METHODS

We searched MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) up to 26 March 2020. We searched clinicaltrials.gov, the World Health Organization trials portal, and several international registries and joint registries up to March 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing knee replacement with use of a tourniquet versus without use of a tourniquet and non-randomised studies with more than 1000 participants. Major outcomes included pain, function, global assessment of success, health-related quality of life, serious adverse events (including venous thromboembolism, infection, re-operation, and mortality), cognitive function, and survival of the implant. Minor outcomes included blood loss, economic outcomes, implant stability, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full texts, extracted data, performed risk of bias assessments, and assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 41 RCTs with 2819 participants. Trials included from 20 to 199 participants. Mean age ranged between 58 and 84 years. More than half of the RCTs had unclear risk of selection bias and unclear risk of performance and detection bias due to absence of blinding of participants and surgeons. Major outcomes Pain: at postoperative day 1, pain (on a scale from zero to 10, with higher scores indicating worse pain) was ranked at 4.56 points after surgery without a tourniquet and at 1.25 points (MD) higher (95% CI 0.32 higher to 2.19 higher) with a tourniquet (8 studies; 577 participants), for an absolute difference of 12.5% higher pain scores (95% CI 3.2% higher to 21.9% higher) and a relative difference of 19% higher pain scores (95% CI 3.4% higher to 49% higher) with a tourniquet. Evidence for these findings was of moderate certainty, downgraded due to risk of bias. Knee replacement with a tourniquet probably led to higher postoperative pain scores at day 1, although this difference may or may not be noticeable to patients (based on a minimal clinically important difference (MCID) of 1.0). Function: at 12 months, tourniquet use probably makes little or no difference to function, based on an MCID of 5.3 for Knee Society Score (KSS) and 5.0 for Oxford Knee Score (OKS). Mean function (on a scale from 0 to 100, with higher scores indicating better outcomes) was 90.03 points after surgery without a tourniquet and was 0.29 points worse (95% CI 1.06 worse to 0.48 better) on a 0 to 100 scale, absolute difference was 0.29% worse (1.06% worse to 0.48% better), with a tourniquet (5 studies; 611 participants). This evidence was downgraded to moderate certainty due to risk of bias. Global assessment of success: low-certainty evidence (downgraded due to bias and imprecision) indicates that tourniquet use may have little or no effect on success. At six months, 47 of 50 (or 940 per 1000) reported overall successful treatment after surgery without a tourniquet and 47 of 50 (or 940 per 1000) with a tourniquet (risk ratio (RR) 1.0, 95% CI 0.91 to 1.10) based on one study with 100 participants. Health-related quality of life: at six months, tourniquet may have little or no effect on quality of life. The 12-Item Short Form Survey (SF-12) score (mental component from zero to 100 (100 is best)) was 54.64 after surgery without a tourniquet and 1.53 (MD) better (95% CI 0.85 worse to 3.91 better) with a tourniquet (1 study; 199 participants); absolute difference was 1.53% better (0.85% worse to 3.91% better). Evidence was of low certainty, downgraded due to risk of bias and small number of participants. Serious adverse events: the risk of serious adverse events was probably higher with tourniquet; 26 of 898 (29 per 1000) reported events following surgery without a tourniquet compared to 53 of 901 (59 per 1000) with a tourniquet (RR 1.73, 95% CI 1.10 to 2.73) in 21 studies (1799 participants). Twenty-nine more per 1000 patients (95% CI 3 to 50 more per 1000 patients) had a serious adverse event with a tourniquet. Forty-eight (95% CI 20 to 345) participants would need to have surgery without a tourniquet to avoid one serious adverse event. This evidence was downgraded to moderate certainty due to risk of bias. Cognitive function: one study reported cognitive function as an outcome; however the data were incompletely reported and could not be extracted for analysis. Survival of implant: it is uncertain if tourniquet has an effect on implant survival due to very low certainty evidence (downgraded for bias, and twice due to very low event rates); 2 of 107 (19 per 1000) required revision surgery in the surgery with a tourniquet group compared to 1 of 107 (9 per 1000) without a tourniquet group at up to two years' follow-up (RR 1.44, 95% CI 0.23 to 8.92). This equates to a 0.4% (0.7% lower to 7% more) increased absolute risk in surgery with a tourniquet.

AUTHORS' CONCLUSIONS

Moderate certainty evidence shows that knee replacement surgery with a tourniquet is probably associated with an increased risk of serious adverse events. Surgery with a tourniquet is also probably associated with higher postoperative pain, although this difference may or may not be noticeable to patients. Surgery with a tourniquet does not appear to confer any clinically meaningful benefit on function, treatment success or quality of life. Further research is required to explore the effects of tourniquet use on cognitive function and implant survival, to identify any additional harms or benefits. If a tourniquet continues to be used in knee replacement surgery, patients should be informed about the potential increased risk of serious adverse events and postoperative pain.