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PurposeThe use of an intraoperative tourniquet for total knee arthroplasty (TKA) is a common practice. However, the effectiveness and safety are still questionable. A systematic review was conducted to examine that whether using a tourniquet in TKA was effective without increasing the risk of complications.MethodsA comprehensive literature search was done in PubMed Medicine, Embase, and other internet database. The review work and the following meta-analysis were processed to evaluate the role of tourniquet in TKA.ResultsEight randomized controlled trials and three high-quality prospective studies involving 634 knees and comparing TKA with and without the use of a tourniquet were included in this analysis. The results demonstrated that using a tourniquet could decrease the measured blood loss but could not decrease the calculated blood loss, which indicated actual blood loss. Patients managed with a tourniquet might have higher risks of thromboembolic complications. Using the tourniquet with late release after wound closure could shorten the operation time; whereas early release did not show this benefit.ConclusionsThe current evidence suggested that using tourniquet in TKA may save time but may not reduce the blood loss. Due to the higher risks of thromboembolic complications, we should use a tourniquet in TKA with caution.

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Diaminoanthracene derivatives 9,10-bis(1-naphthylphenylamino)anthracene (α-NPA), 9,10-bis(2-naphthylphenylamino)anthracene (β-NPA), 9,10-bis(m-tolylphenylamino)anthracene (TPA), and 9,10-bis(diphenylamino)anthracene (PPA) were conveniently synthesized from the corresponding diarylamine and 9,10-dibromoanthracene in the presence of Pd(OAc)2, tri-tert-butylphosphine, and sodium tert-butoxide in o-xylene. Electroluminescent devices using α-NPA, β-NPA, and PPA as the hole transporters and host emitters were made. Devices consisting of diaminoanthracene (α-NPA, β-NPA, or PPA)/Alq3 were shown to emit intensive green light from the diaminoanthracene layer instead of the Alq3 layer. The device performance can be further improved by employing CuPc as the hole-injection layer, α-NPB or m-MTDATA as the hole-transporting layer, and Alq3 or TPBI as the electron-transporting layer. Very high brightness, current, and power efficiencies and excellent CIE coordinates can be achieved by a suitable combination of these layers. For example, device K, which consists of m-MTDATA(20 nm)/β-NPA(40 nm)/TPBI(50 nm), emits green light at 530 nm and shows a maximum external quantum efficiency of 3.68%, current efficiency of 14.79 cd/A, power efficiency of 7.76 lm/W, and maximum brightness of 64991 cd/m2.

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