In this study, the LEX was successfully used in patients after total joint arthroplasty of the lower extremities, and no severe adverse events occurred. Overall, 80% of subjects completed the 1-week protocol. This rate of acceptance is comparable to that of IPC, which is reported to be 81% [17, 25].
With respect to the safety of a device that affects circulatory dynamics through exercise, none of the measured values for systolic or diastolic blood pressure, pulse rate, and SpO2 exceeded the exercise cancellation standard set by the Japanese Association of Rehabilitation Medicine [26] (Table 5). This suggests that it is unlikely that exercising with the LEX will cause any hemodynamic complication.
Table 5
Stop exercise criteria in this study.
|
Stop exercise criteria
|
Present study
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Systolic blood pressure
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Increasing > 40mmHg
|
Increasing 12mmHg
|
Diastolic blood pressure
|
Increasing > 20mmHg
|
Increasing 19mmHg
|
Pulse rate
|
Over 140bpm
|
Max 112bpm
|
SpO2
|
Moderate breathing difficulties
|
No breathing difficulties
|
Criteria are according to the guidelines for safety management and promotion in rehabilitation medicine, proposed by the Japanese Association of Rehabilitation Medicine [26].
|
According to the ACCP [8] and AAOS guidelines [9] the main aim of thromboprophylaxis is the prevention of lethal or symptomatic VTE; compared to previous guidelines, anticoagulant therapy indications are more restricted due to the risk of major bleeding complications and cost-effectiveness issues. Specifically, the AAOS guidelines clarify that pharmacological prophylaxis is only recommended for patients who are not at elevated risk of bleeding after surgery [27]. This guideline recommends mechanical prevention for asymptomatic VTE in patients with high risk of bleeding.
Sashi et al. [28] studied the VTE rates in total hip and knee arthroplasty between 2002 and 2011 and found that, despite a slight decrease in VTE incidence related to both surgeries, PE rates remained stable. In detail, the overall median DVT and PE incidences in the cited study were, respectively, 0.40 and 0.23 in primary THA, and 0.62 and 0.34 in primary TKA. Chan et al. [29] conducted a systematic review of randomized controlled trials comparing the rates of VTE and bleeding due to pharmacological prophylaxis after THA or TKA and found an overall VTE rate of 0.99%, which is similar to that of previous studies. However, the post-operative bleeding rate was 3.44%, more than three times the VTE rate. Fuji et al. (4) studied that the development, prophylaxis, and treatment of VTE and bleeding events in 36,947 patients who had undergone orthopedic surgeries of the lower extremities from 2008 to 2013 using a healthcare database. They reported that the incidences of DVT, PE, and bleeding were 1.3%, 0.2%, and 1.0% for TKA and 0.9%, 0.2%, and 1.1% for THA. Therefore, the rate of bleeding complications due to antithrombotic therapy was higher than that of PE in both studies.
In turn, Tsuda et al. [30] reported the incidence of DVT using mechanical prophylaxis solely. Their study showed that among 184 cases of hip surgery receiving only IPC and GCS (patients with trauma were excluded), 5% were diagnosed with distal thromboses according to ultrasonic tests conducted in postoperative week 3.
Considering the relatively high incidence of bleeding events, the current opinion is that individual risk analyses for VTE are needed [3, 31]. In this regard, we are considering to design study protocols using LEX as mechanical prophylaxis according to VTE risk stratification, in addition or not to pharmacological prophylaxis.
Finally, in view of the current pandemic, it is worth noting that coronavirus disease 2019 (COVID-19) increases the risk of VTE significantly [32, 33]. In addition to this, self-isolation periods prior to lower limb arthroplasty may increase the thrombotic risk further [31]. In a period in which close contact should be reduced to a minimum, mechanical devices which enable self-managed exercise, such as the LEX, may be valuable for both a safe DVT prophylaxis and an appropriate rehabilitation.
There were some limitations in this study. First, the sample size was too small to evaluate effectiveness in the prevention of VTE. However, considering that DVT after arthroplasty of the lower limbs is very common, it may be significant that no case of DVT was observed in our cohort. Second, we analyzed LEX use in patients who were independent in their ADLs before surgery and therefore could resume ambulation relatively soon after surgery. Third, patients in our study received other prophylactic methods such as IPC and anticoagulants, which can account for the absence of VTE cases. We are considering to evaluate the efficacy of the LEX in combination with established strategies to prevent VTE in bedridden patients.