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RCT
ACE Report #5883

TKA: best outcome with tourniquet inflation before incision & deflation when cement harden


Study Type:Randomized Trial
OE Level Evidence:2
Journal Level of Evidence:2

A randomized double-blind clinical trial of tourniquet application strategies for total knee arthroplasty

Knee Surg Sports Traumatol Arthrosc. 2013 Dec;21(12):2790-9. doi: 10.1007/s00167-012-2221-1. Epub 2012 Sep 28

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Synopsis

43 patients undergoing total knee arthroplasty were randomized to three different tourniquet protocols to determine which was optimal for blood loss and fit-to-discharge outcomes. The three tourniquet applications were as follows: inflation just prior to incision and deflation after cement hardening (Group 1), inflation just prior to cementing and deflation after cement solidification (Group 2), and inflation just prior to skin incision and deflation after wound closure and compressive bandaging (Group 3). The results indicated that Group 1 had lowest blood loss and best outcome on the Timed Up-&-Go (TUG test; factor of discharge criteria).

Publication Funding Details +
Funding:
Non-Industry funded
Sponsor:
ESA Research Grant 2009
Conflicts:
None disclosed

Risk of Bias

8/10

Reporting Criteria

20/21

Fragility Index

N/A

Was the allocation sequence adequately generated?

Was allocation adequately concealed?

Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?

Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?

Blinding Patients: Was knowledge of the allocated interventions adequately prevented?

Was loss to follow-up (missing outcome data) infrequent?

Are reports of the study free of suggestion of selective outcome reporting?

Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?

Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?

Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?

Yes = 1

Uncertain = 0.5

Not Relevant = 0

No = 0

The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.

4/4

Randomization

4/4

Outcome Measurements

4/4

Inclusion / Exclusion

4/4

Therapy Description

4/5

Statistics

Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65

The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.

Why was this study needed now?

A risk/benefit relationship exists with tourniquet use in total knee arthroplasty. Advantages include a better operative field, easier cementing and reduced duration of surgery. However, the disadvantages of tourniquet use include soft tissue ischemia, increased risk of venous thromboembolic complications, joint swelling and stiffness, and thigh pain. The timing of tourniquet application in surgery has been implicated as having a profound effect on hematological outcomes, including blood loss and transfusion necessity. However, continued debate exists on optimal tourniquet use.

What was the principal research question?

How do three different tourniquet strategies (inflation just prior to incision and deflation after cement hardening; inflation just prior to cementing and deflation after solidification; inflation just prior to skin incision and deflation after wound closure and compressive bandaging) compare in total knee arthroplasty, assessed over the perioperative period? Does a longer tourniquet application reduce blood loss and improve discharge criteria in comparison to tourniquet protocols of shorter duration, assessed over the perioperative period?

Study Characteristics -
Population:
43 patients undergoing total knee arthroplasty using the anterior medial parapatellar and standard medial subvastus arthrotomy techniques. All procedures used the same prosthesis (AGC V2 Posterior Cruciate Retaining Total Knee system, Biomet UK Ltd, Bridgend, UK) with cementing (Refobacin Bone Cement R, Biomet Orthopaedics, Switzerland GmbH, Switzerland). Suction drains were placed at the completion of the procedure. Drain tube was clamped for 3 hours postoperatively, released for 10 minutes thereafter, then clamped and closed again until 7am the following morning.
Intervention:
Group 3: Following elevation and exsanguination of the index limb, the tourniquet (Automatic Tourniquet System A.T.S. 3000, Zimmer Orthopaedic Surgical Products, Dover, OH, USA) was inflated prior to skin incision and deflated following wound closure and compressive dressing (Mean age: 72.9 +/- 4.5) (n=14; 12 patients analyzed, 1M/11F)
Comparison:
Group 1: Following elevation and exsanguination of the index limb, the tourniquet (Automatic Tourniquet System A.T.S. 3000, Zimmer Orthopaedic Surgical Products) was inflated just before skin incision and deflated after cement solidification (Mean age: 68.2 +/- 6.4) (n=14; 12 patients analyzed, 1M/11F) Group 2: Following elevation and exsanguination of the index limb, the tourniquet (Automatic Tourniquet System A.T.S. 3000, Zimmer Orthopaedic Surgical Products) was inflated just before cement was laid and deflated after the cement had solidified (Mean age: 67.3 +/- 6.4) (n=15; 12 patients analyzed, 3M/9F)
Outcomes:
Blood loss was calculated based on arterial hemoglobin (Hb) concentration and hematocrit (Hct) levels. Three methods were used for this estimation: the 'classic' formula (based on preoperative and postoperative Hb concentration), the modified Gross formula (based on fractional change of Hct levels), and Shander's modification of the Gross formula. Each of the previous formulae were also estimated based on two calculations of estimated normal blood volume: Nader's formula and the formula recommended by the Expert Panel on Radionuclides of the International Council of Haematology. Therefore, 6 calculations were for estimated blood loss in the 24h after the start of surgery. Fit-to-discharge criteria were as follows: pain control via NSAIDs only in the previous 24h, <20s on the Timed Up-&-Go (TUG) test, normal wound healing and body temperature <37.7 degrees C in the previous 24h.
Methods:
RCT; Single Center; Double-blind (assessor and patient blinded), Interim report
Time:
Perioperative measurements until discharge.

What were the important findings?

  • Mean tourniquet pressure (SD) and median tourniquet time [25th; 75th percentiles] were 288mmHg (53) and 37min [32;45] in Group 1, 331mmHg (30) and 11min [10;12] in Group 2, and 316mmHg (55) and 60min [57;72] in Group 3.
  • The average duration of surgery was 62.0min in Group 1, 59.8min in Group 2, and 60.6min in Group 3. The difference between groups was not significant (p>0.05).
  • Estimated blood volume loss in Group 1 was significantly lower than Group 2 for all methods of calculation (all P<0.05). Group 2 and Group 3 only significantly differed in estimated blood volume loss when calculated using the 'Classic' formula, with lower estimated blood volume loss for Group 3 compared to Group 2 (p=0.050). This formula is based on recommendations by the International Council for Standardization in Haematology
  • No significant differences in the first 6 postoperative days (POD) were noted between groups for fit-to-discharge criteria concerning pain management, wound healing, or body temperature. TUG tests were significantly better among patients of Group 1 compared to both Group 2 and Group 3 (P=0.023 and 0.033, respectively). Subsequently, achieving fit-to-discharge criteria was significantly better in Group 1 compared to Group 3 (p=0.030); the difference between Group 1 and Group 2 was not significant.
  • No complications were recorded over the first 6 postoperative days.

What should I remember most?

Longer tourniquet application was not associated with reduced blood loss and earlier attainment of discharge criteria compared to shorter tourniquet applications. Of the three strategies employed, inflation of the tourniquet just before skin incision and deflation after cement solidification appeared to have the optimal effect on blood loss and fit-to-discharge outcomes.

How will this affect the care of my patients?

The evidence presented in this study suggests that a tourniquet strategy of inflation before skin incision and deflation after cement hardening in total knee arthroplasty may yield the best results of the three strategies evaluated. However, it is important to note that as this was an interim report, definitive conclusions on the efficacy of each tourniquet protocol relative to the others should be withheld until further investigation is completed.

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