Prevention of deep-vein thrombosis after total hip and knee replacement

Chae

et al. 2017

Knee Surg Relat Res

PurposeTo compare the occurrences of perioperative complications of two anesthetic techniques (general anesthesia [GA] and spinal anesthesia [SA] in patients undergoing primary unilateral total knee arthroplasty (TKA).Materials and MethodsPatients who underwent unilateral primary TKA due to osteoarthritis from January 2005 to January 2014 were retrospectively reviewed. They were divided into two groups: GA (n=490) and SA (n=746). The operation duration, length of perioperative stay in the operation room and occurrences of adverse events in postoperative 30 days (mean, 29.7±3.1 days) were compared. Before multivariate linear or logistic regression analysis, different baseline characteristics were adjusted in the statistical models.ResultsThere were significant intergroup differences in mean age (GA, 68.4±7.2 years; SA, 70.7±7.5 years; p<0.001) and mCCI (GA, 3±1.4; SA, 3.2±1.5; p<0.001). The GA group required longer preoperative room time (+9.4 minutes; p<0.001), postoperative room time (+12.7 minutes; p<0.001), and postoperative hospital stay (+2.5 days; p=0.001) and had more surgical site infections (5 [1%] vs. 0 [0%]; p=0.005) and blood transfusion (205 [41.8%] vs. 262 [35.1%]; p=0.01). No differences in operative duration and other adverse events were identified.ConclusionsWe should cautiously consider that GA may be associated with slightly increased preoperative and postoperative room times, postoperative hospital stay, transfusion and surgical site infection rates in primary unilateral TKA.

“…Regional anesthesia has been reported to protect against DVT and PE in patients undergoing total joint arthroplasty24,25). However, no such tendency was evident in this study.…”

Section: Discussioncontrasting

confidence: 66%

Comparison of Short-Term Complications of General and Spinal Anesthesia for Primary Unilateral Total Knee Arthroplasty

Chae

et al. 2017

Knee Surg Relat Res

“…The VTE incidence was 1.38% (5 subjects) in subjects using a GCS and 1.22% (2 subjects) in those that did not, although this was not a statistically significant difference. Even if the present study did not utilize the combined IPC, the utilization of LMWH combined with IPC would be effective, based on a previous study demonstrating that the prophylactic effects of VTE is more pronounced with LMWH+IPC than with LMWH LMWH+GCS [33], further supported by multiple recent recommendations. In this study, the incidence of VTE was significantly affected by length of stay at the intensive care unit ( Table 2); the incidence of VTE during a short stay, 1 -2 days, was 7.6% (1 of 13) while the incidence during a long stay, more than 3 days, was 40% (2 of 5).…”

Section: Discussionmentioning

confidence: 69%

Incidence and Clinical Characteristics of Deep Vein Thrombosis (DVT) after Total Knee Arthroplasty (TKA) with DVT Chemoprophylaxis

Won¹,

Kim²,

Jun³

et al. 2014

WJCD

Objective: Deep vein thrombosis (DVT) after total knee arthroplasty (TKA) is very common and leading cause of death due to this procedure. The objective of this study was to investigate the incidence and clinical characteristics of DVT after TKA with DVT chemoprophylaxis. Methods: This is a prospective cohort study in single institution. The patients received postoperative DVT chemoprophylaxis (low molecular weight heparin (LMWH) or Fondaparinux), followed by duplex ultrasonography to check for DVT 1-2 weeks after TKA. The clinical characteristics were summarized and analysed by chi-square test and regression analysis. Results: Five hundred and thirty four patients were enrolled from January 2007 to December 2010. DVT chemoprophylaxis was administered in 524 (98.1%) of the 534 patients. DVT occurred in 9 subjects (1.69%); 8 subjects had DVT in the leg, and 1 subject had a pulmonary embolism. Among them, asymptomatic DVT was observed in 5 patients (0.94%). Univariate analysis showed that surgical methods (revision, P = 0.0007), body mass index (BMI) (>25, P = 0.0028), low platelet count (less than 150 × 10 3 , P = 0.0219), time in the intensive care unit (ICU) (P < 0.0001), no administration of prophylactic LMWH (P = 0.0392), and a history of DVT (P < 0.0001) were significant risk factors of DVT. Conclusions: The incidence of DVT was 1.69% after TKA with prophylactic antithrombotic therapy. Revision surgery, BMI, low platelet count, time in ICU, absence of prophylactic LMWH and history of DVT were significant risk factors of DVT.

“…The total pressure applied by the ACB has two components, the mechanical pressure which is the pressure resulting from the mechanical stress in the ACB before actuating the ACB, and the actuation pressure, which is the pressure variation after actuating the ACB. The ACB is assumed to be made out of a flat DEA with length L [ 11 ]. This flat DEA can be bent to form a cylinder, whose external radius is .…”

Section: Analytical Modeling Of the Dea On A Simulated Human Calfmentioning

confidence: 99%

“…In particular, DEAs can apply a variable (time-dependent) mechanical compression using an input electrical stimulus. Variable compression was shown to be more efficient than a static compression in different studies [ 11 , 12 ]. Moreover, DEAs are lightweight, portable and very fast with experimental time responses as short as 2 ms [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

On the design of a DEA-based device to pot entially assist lower leg disorders: an analytical and FEM investigation accounting for nonlinearities of the leg and device deformations

2015

BackgroundOne of the recommended treatments for disorders associated with the lower extremity venous insufficiency is the application of external mechanical compression. Compression stockings and elastic bandages are widely used for the purpose of compression therapy and are usually designed to exert a specified value or range of compression on the leg. However, the leg deforms under external compression, which can lead to undesirable variations in the amount of compression applied by the compression bandages. In this paper, the use of an active compression bandage (ACB), whose compression can be regulated through an electrical signal, is investigated. The ACB is based on the use of dielectric elastomer actuators. This paper specifically investigates, via both analytical and non-linear numerical simulations, the potential pressure the ACB can apply when the compliancy of the human leg is taken into account. The work underpins the need to account for the compressibility of the leg when designing compression garments for lower extremity venous insufficiency.MethodsA mathematical model is used to simulate the volumetric change of a calf when compressed. Suitable parameters for this calf model are selected from the literature where the calf, from ankle to knee, is divided into six different regions. An analytical electromechanical model of the ACB, which considers its compliancy as a function of its pre-stretch and electricity applied, is used to predict the ACB’s behavior. Based on these calf and ACB analytical models, a simulation is performed to investigate the interaction between the ACB and the human calf with and without an electrical stimulus applied to the ACB. This simulation is validated by non-linear analysis performed using a software based on the finite element method (FEM). In all simulations, the ACB’s elastomer is stretched to a value in the range between 140 and 220 % of its initial length.ResultsUsing data from the literature, the human calf model, which is examined in this work, has different compliancy in its different regions. For example, when a 28.5 mmHg (3.8 kPa) of external compression is applied to the entire calf, the ankle shows a 3.7 % of volume change whereas the knee region undergoes a 2.7 % of volume change. The paper presents the actual pressure in the different regions of the calf for different values of the ACB’s stretch ratio when it is either electrically activated or not activated, and when compliancy of the leg is either considered or not considered. For example, results of the performed simulation show that about 10 % variation in compression in the ankle region is expected when the ACB initially applies 6 kPa and the compressibility of the calf is first considered and then not considered. Such a variation reduces to 5 % when the initial pressure applied by the ACB reduced by half.ConclusionsComparison with non-linear FEM simulations show that the analytical models used in this work can closely estimate interaction between an active compression bandage and a human calf. In addi...