Critical Appraisal: Clinical Trial on Total Knee Arthroplasty

This report presents a critical appraisal of a randomized controlled trial (RCT) investigating the efficacy of intravenous and intra-articular tranexamic acid (TXA) in patients undergoing total knee arthroplasty (TKA). The study aimed to determine the impact of TXA on blood loss and postoperative outcomes, addressing the research gap concerning the optimal use of TXA in TKA patients. The report meticulously analyzes the research design, which utilized an RCT methodology, assessing its strengths in reducing bias through allocation concealment and random sampling. The appraisal evaluates the sample size, eligibility criteria, and adherence to RCT principles, highlighting the appropriateness of the research design in answering the research question. Furthermore, the report examines the study's findings, which indicated improved postoperative outcomes, including reduced blood loss, in patients receiving both intravenous and intra-articular TXA. The analysis also acknowledges the study's limitations, such as the absence of a discussion on the theoretical aspects of the outcomes. Overall, the critical appraisal provides a comprehensive assessment of the clinical trial, emphasizing its contributions to the field and suggesting avenues for future research.

Running head: CRITICAL APPRAISAL
Critical appraisal
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The article focused on exploring the effect of intravenous injection of fibrinolytic
inhibitor tranexamic acid (TXA) combined with intra-articular injection (IA) of TXA in patients
who had undergone total knee arthroplasty (TKA). From the review of the research aim, it can be
said that the paper has a clear and focussed research question. The research aim and significance
of the study was further confirmed by review of introduction and literature review on the topic.
The key research problem that the study aimed to address included the issue of blood loss and
anaemia in patients after TKA. As blood loss after TKA result in increased hospital stay and
increase in economic and clinical burden, the literature review revealed about recent evidence of
the efficacy of TXA in reducing blood loss in a mouse model. The research gap that favoured
research in this area included lack of research to investigated about the efficacy of TXA in
patients after TKA (1). Hence, the research aim and question is justified by appropriate
discussion regarding gaps in research and research problem (2).
To investigate about the research topic, the study used randomized controlled trial (RCT)
method as the research design. This can be said as the researcher conducted the study with two
groups of people. The first group received TXA injection before and after TKA. In addition, the
second group received TKA by IV and by IA. The strength of using RCT is that it comes under
the highest level of evidence under evidence hierarchy. The process undertaken during RCT such
as allocation concealment, random sampling and equal treatment of group apart from
intervention plays a role in reducing biases and risk of systematic errors (3). Hence, this research
design is reflective of high quality research. In addition, the selection of research design is
appropriate according to the research question. The research aimed to study the effect of an
intervention (TXA) on patient outcome (blood loss after TKA) and RCT is the best method to

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evaluate effect of an intervention and compare the outcome by comparison with intervention and
treatment group (4). However, the judgment regarding the quality will be done by assessing
whether the paper followed appropriate sample recruitment and data collection technique
according to RCT study or not.
The sample for the study included 150 patients undergoing TKA. The sample size is
appropriate considering quantitative method of data collection. However, no sample size
calculation was done to estimate sample size. The eligibility criteria for sample selection were
also clearly defined. The exclusion criteria focused on eliminating patients before TKA operation
and patient who had contraindication to TKA. The review of these exclusion criteria indicates
that researcher considered factors that could contribute to biases or those which can confound the
study outcome. Therefore, these considerations enhance the validity of research. In addition,
core features of RCT trial were followed. This can be said because allocation concealment was
maintained and blindness of sample group was done to ensure randomness of the process.
Random allocation was done by pharmacist. Research evidence gives the argument that a robust
RCT is one that mandatorily uses allocation concealment. This is the key to effective
randomization process. Use of allocation concealment also reflects implementation of techniques
to prevent selection bias. Allocation concealment prevents researcher from identifying which
participants are assigned to which group and this process helps to prevent risk of bias (5). Hence,
this is reflective of validity of the research methods.
A successful research design is one which is able to give answer to the research question
and meet the key objectives of research. To assess this aspect, the study used evaluation of knee
joint function, blood loss and post operative events to understand the benefit of the intervention.
The review of the research findings of the article revealed that patients receiving IV plus IA

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TXA had better post operative outcomes related to total blood loss and maximum haemoglobin
drop compared to other patient group. The effectiveness of the finding was also judged by 6
months follow up. This helps to develop knowledge regarding long term benefit of IV and IA
TXA in preventing complication for patients. Hence, the study addressed the research aim.
However one limitation of the study was that it lacked discussion on theoretical aspects of the
outcomes. Hence, as there is lack of experimental studies on ways to prevent complication after
TKA, future studies can focus on addressing this aspect. This will help to ensure that burden of
hospitalization is reduced for patients with TKA.

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References:
1. Zhang YM, Yang B, Sun XD, Zhang Z. Combined intravenous and intra-articular
tranexamic acid administration in total knee arthroplasty for preventing blood loss and
hyperfibrinolysis: A randomized controlled trial. Medicine. 2019 Feb;98(7).
2. Elwood M. Critical appraisal of epidemiological studies and clinical trials. Oxford
University Press; 2017 Mar 1.
3. Burns PB, Rohrich RJ, Chung KC. The levels of evidence and their role in evidence-
based medicine. Plastic and reconstructive surgery. 2011 Jul;128(1):305.
4. Rosenberger WF, Lachin JM. Randomization in clinical trials: theory and practice. John
Wiley & Sons; 2015 Nov 23.
5. Kim J, Shin W. How to do random allocation (randomization). Clinics in orthopedic
surgery. 2014 Mar 1;6(1):103-9.