Topical Tranexamic Acid in Total Knee Replacement: What Research Shows

Total knee replacement is a commonly performed procedure for patients with advanced knee joint damage, particularly when osteoarthritis causes persistent pain and limits mobility. Although the operation can improve pain and function, blood loss during and after surgery is an important consideration.
 

One medication used to help reduce surgical blood loss is tranexamic acid (TXA). It works by helping stabilise blood clots and limiting the breakdown of clots formed during surgery.
 

A 2020 study published in Archives of Orthopaedic and Trauma Surgery and titled "Higher doses of topical tranexamic acid safely improves immediate functional outcomes and reduces transfusion requirement in total knee arthroplasty" examined whether the amount of topical TXA used during total knee arthroplasty affected blood transfusion requirements and early postoperative outcomes. The study compared 1 g and 2 g doses of topical TXA in 104 patients undergoing total knee replacement.
 

Importantly for Singapore's orthopaedic community, Dr Wang Lushun of Arete Orthopaedic Centre was one of the authors of this research, alongside ChengHan Wu and Cheryl Tan. The authors were affiliated with the Department of Orthopaedics at Ng Teng Fong General Hospital in Singapore at the time of the study.

What Is Tranexamic Acid?

Tranexamic acid is a medication that helps reduce bleeding by preventing the breakdown of blood clots.
 

During surgery, the body naturally activates mechanisms that control bleeding. Once a clot has formed, another process called fibrinolysis can break it down. TXA works by interfering with this process, helping the clot remain stable.
 

In total knee replacement, TXA can be administered in different ways, including:

• Intravenously

• Topically around the surgical site

• Directly into the joint in certain protocols
   

The study discussed here specifically examined topical administration, rather than comparing intravenous and topical treatment.

Why Is Blood Loss an Important Consideration in Knee Replacement?

Total knee replacement involves removing damaged joint surfaces and placing artificial components to restore the function of the knee.
 

As with other major operations, blood loss can occur during and after surgery. Significant blood loss may contribute to a reduction in haemoglobin levels and, in some cases, the need for a blood transfusion.
 

Reducing unnecessary blood loss may therefore be an important part of perioperative management.
 

TXA has been increasingly used in knee replacement because it can reduce bleeding. However, the appropriate dose and method of administration have varied between studies and clinical protocols. The researchers noted that there was no clear consensus on the optimal topical dose at the time of their study.

What Did the Study Investigate?

The researchers wanted to compare two doses of topical TXA:

• 1 g of topical TXA

• 2 g of topical TXA
   

They looked at several outcomes, including:

• Blood loss

• Blood transfusion requirements

• Early knee function

• Postoperative pain

• Complications related to TXA
   

The study therefore looked beyond blood loss alone and considered whether the different doses were associated with differences in the patient's immediate postoperative recovery.

How Was the Research Conducted?

The study was a retrospective cohort study involving 104 patients who underwent total knee arthroplasty at a single institution under a single surgeon.
 

Of the 104 patients:

• 61 received 1 g of topical TXA

• 43 received 2 g of topical TXA
   

The researchers assessed blood loss using changes in haemoglobin and haematocrit levels after surgery. They also recorded blood transfusions, early postoperative knee movement, pain scores and complications.
 

This study design is important when interpreting the findings. Because it was retrospective and involved a relatively small group of patients from one institution and one surgeon, the findings show an association within this study population rather than proving that the same results will occur in every patient or clinical setting.

What Did the Researchers Find?

1. The Higher-Dose Group Had Fewer Transfusions

One of the clearest findings involved blood transfusion requirements.
 

The average transfusion requirement was higher in the 1 g group than in the 2 g group:

• 1 g group: 0.11

• 2 g group: 0.00
   

The difference was statistically significant, with a p-value of 0.034.
 

This means that, within the study, patients who received 2 g of topical TXA had a lower transfusion requirement than those who received 1 g.
 

It does not mean that every patient receiving the higher dose will avoid a transfusion, as transfusion decisions depend on individual blood loss, haemoglobin levels, symptoms and other clinical factors.

2. The Higher-Dose Group Reported Less Pain on the First Postoperative Day

The study also examined pain on the first day after surgery.
 

The mean pain score was:

• 4.02 in the 2 g group

• 5.43 in the 1 g group
   

The difference was statistically significant, with a p-value of less than 0.01.
 

This finding suggests that the patients who received 2 g of topical TXA reported lower pain scores on the first postoperative day in this study.
 

However, the study was not designed to establish that the higher dose of TXA directly caused the reduction in pain. Other factors involved in postoperative pain management may also influence patient-reported pain.

3. Early Knee Movement Results Were Not Better With the Higher Dose

Interestingly, the higher dose did not produce better results for every measured functional outcome.
 

The mean range of motion on postoperative day one was:

• 72.1 degrees in the 1 g group

• 63.7 degrees in the 2 g group
   

The difference was statistically significant, but the direction of the difference favoured the 1 g group for this particular measurement.
 

This is an important detail because it shows why individual study findings should not be simplified into the conclusion that a higher dose improves every aspect of early recovery.
 

The researchers considered overall immediate postoperative function alongside pain and transfusion requirements when drawing their conclusions.

4. No Significant Difference in TXA-Related Complications Was Found

The researchers also compared complications associated with administration of TXA.
 

They reported no statistically significant difference in TXA-related complications between the two groups.
 

This supported the study's conclusion that the higher topical dose was not associated with an increased rate of the complications measured in the study.
 

However, this should not be interpreted as proof that a higher dose of topical TXA is risk-free for every patient. Individual suitability, medical history and other risk factors remain important when deciding whether and how TXA should be used.

What Do These Findings Mean for Patients Undergoing Knee Replacement?

For patients, the research provides insight into one aspect of total knee replacement management: controlling blood loss around the time of surgery.
 

The study found that, within its patient group, 2 g of topical TXA was associated with fewer transfusion requirements and lower pain scores on the first postoperative day compared with 1 g. It did not show better results across every early functional measure, as the 1 g group had a higher mean range of motion on postoperative day one.
 

The findings therefore contribute to the discussion about how topical TXA dosing may influence outcomes after total knee replacement.
 

They do not establish that a 2 g dose is universally preferable for every patient.

Why Is the Route of TXA Administration Relevant?

TXA can be administered through different routes, and the method may affect how the medication is delivered.
 

Topical administration is applied around the surgical area rather than being given systemically through an intravenous route.
 

One reason topical administration has attracted interest is the potential to reduce systemic exposure compared with some systemic administration approaches. The study specifically focused on topical TXA and noted the growing use of this approach in total knee arthroplasty.
 

Other research has also examined different routes of TXA administration in total knee replacement, including intravenous, intra-articular and peri-articular approaches. This broader research shows that TXA administration remains an area of ongoing investigation, with dosing and delivery methods varying between studies.

Does This Mean All Knee Replacement Patients Should Receive 2 g of TXA?

Not necessarily.
 

The study compared two specific topical TXA doses in a particular patient population. It was not a large randomised clinical trial designed to establish a universal dosing recommendation.
 

The appropriate use and dose of TXA may depend on factors such as:

• Patient health

• Medical history

• Bleeding risk

• Type of surgery

• Surgical technique

• Other medications

• The surgeon's protocol
   

Doctors may also consider the broader evidence available when determining how TXA should be used.

What Are the Limitations of the Research?

Understanding the limitations is important when interpreting the findings.

Retrospective Study Design

The researchers reviewed existing patient data rather than randomly assigning patients prospectively to different treatment groups.
 

This means the study can identify associations but has limitations when determining cause and effect.

Relatively Small Patient Group

The study involved 104 patients, with 61 receiving 1 g and 43 receiving 2 g.
 

A larger study population could provide more robust evidence.

Single Institution

All patients were treated at one institution, which may limit how widely the findings can be generalised to other hospitals or surgical settings.

Single-Surgeon Study

The procedures were performed under a single surgeon. Differences in surgical technique and perioperative care between surgeons may affect outcomes.

Short-Term Outcomes

The research focused on immediate postoperative function, pain, transfusion requirements and complications. It does not establish whether the different TXA doses result in differences in long-term knee function or implant outcomes.
 

These limitations do not make the findings unimportant. Rather, they provide context for how the results should be interpreted.

What Does This Research Add to Total Knee Replacement Care?

The study contributes to research examining how the use and dosage of TXA may influence blood management and early recovery following total knee replacement.
 

Its findings suggest that, in the study population, the 2 g topical dose was associated with:

• Lower transfusion requirements

• Lower pain scores on postoperative day one

• No statistically significant difference in TXA-related complications
   

At the same time, the 1 g group recorded a higher mean range of motion on postoperative day one, demonstrating that the effect of dosing was not uniformly favourable across all measured outcomes.
 

This highlights the importance of evaluating several clinical outcomes rather than focusing on a single measure.

What Should Patients Ask Before Total Knee Replacement?

Patients preparing for knee replacement may wish to ask their orthopaedic surgeon:

• How will blood loss be managed during surgery?

• Is tranexamic acid part of the surgical protocol?

• How is TXA administered?

• What factors determine the dose?

• What is my individual risk of requiring a blood transfusion?

• What will pain management involve?

• What can I expect during the first few days of recovery?

• When will I begin physiotherapy and knee exercises?
   

These questions can help patients understand how blood management, pain control and rehabilitation fit into the overall surgical plan.

Dr Wang Lushun's Contribution to the Research

The research was co-authored by Dr Wang Lushun, who was affiliated with the Department of Orthopaedics at Ng Teng Fong General Hospital when the study was conducted. Dr Wang Lushun is now associated with Arete Orthopaedic Centre in Singapore.
 

His contribution to this study forms part of the published research literature examining perioperative management in total knee arthroplasty, specifically the use of topical tranexamic acid and its relationship with blood transfusion requirements and immediate postoperative outcomes.
 

Research into tranexamic acid continues to inform how blood loss is managed during total knee replacement. The 2020 study involving 104 patients compared 1 g and 2 g doses of topical TXA and found that the higher-dose group had lower transfusion requirements and lower pain scores on the first postoperative day. The study did not, however, demonstrate better results across every early functional measure, with the 1 g group recording greater mean knee range of motion on postoperative day one.
 

The findings provide useful evidence about topical TXA dosing in total knee replacement, but they should be interpreted in the context of the study's retrospective design, relatively small sample and single-centre, single-surgeon setting.
 

For patients considering total knee replacement, decisions about medications, surgical techniques and blood management should be made with the treating orthopaedic team based on individual health factors and the available clinical evidence.

Research Reference

Wu C-H, Tan C, Wang L. Higher doses of topical tranexamic acid safely improves immediate functional outcomes and reduces transfusion requirement in total knee arthroplasty. Archives of Orthopaedic and Trauma Surgery. 2020 Dec;140(12):2071-2075. PMID: 32862267. DOI: 10.1007/s00402-020-03591-4.
 

This article is for general information only and should not replace medical advice from a qualified healthcare professional.