UMIN-ICDS Clinical Trial
| Unique ID issued by UMIN | UMIN000062081 |
|---|---|
| Receipt number | R000071034 |
| Scientific Title | Aspirin Co-administration Under Tranexamic Acid Therapy for Preventing Venous Thromboembolism After Total Knee Arthroplasty: A Prospective Double-blind Randomized Controlled Trial Using Lower Limb Ultrasonography |
| Date of disclosure of the study information | 2026/09/04 |
| Last modified on | 2026/06/27 16:21:56 |
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Basic information
Public title
Effect of Aspirin Co-administration Under Tranexamic Acid Therapy on Postoperative Venous Thromboembolism After Total Knee Arthroplasty:
A Prospective Double-blind Randomized Controlled Trial Using Lower Limb Ultrasonography
Acronym
Knee-Thrombo Trial
Scientific Title
Aspirin Co-administration Under Tranexamic Acid Therapy for Preventing Venous Thromboembolism After Total Knee Arthroplasty:
A Prospective Double-blind Randomized Controlled Trial Using Lower Limb Ultrasonography
Scientific Title:Acronym
AT-Knee Trial
Region
| Japan |
Condition
Condition
Osteoarthritis of the knee requiring primary total knee arthroplasty
Classification by specialty
| Orthopedics |
Classification by malignancy
Others
Genomic information
NO
Objectives
Narrative objectives1
Venous thromboembolism (VTE) remains a clinically significant complication after total knee arthroplasty (TKA), and its prevention continues to be an important challenge in perioperative management. In recent years, low-dose aspirin has been increasingly adopted in Western countries as a standard prophylactic agent for postoperative VTE due to its favorable balance of efficacy and safety. At the same time, postoperative knee swelling, subcutaneous bleeding, and pain can delay rehabilitation, highlighting the need for a prophylactic strategy that suppresses thrombosis without increasing postoperative bleeding or inflammation. Tranexamic acid (TXA) is widely used to reduce postoperative bleeding and inflammation, and previous studies have shown that TXA does not increase the risk of VTE. However, no prospective double-blind randomized controlled trials have evaluated the effectiveness and safety of combining postoperative TXA therapy with low-dose aspirin for VTE prevention after TKA.This study aims to determine whether adding low-dose aspirin (100 mg/day for 3 weeks) to a 3-week postoperative oral TXA regimen reduces the incidence of lower limb deep vein thrombosis (DVT) at 3 weeks after TKA, compared with TXA alone. In addition, the study will evaluate the effects of aspirin co-administration on postoperative knee swelling, subcutaneous ecchymosis, pain, range of motion, and other orthopedic outcomes. Through these assessments, the study seeks to clarify the overall efficacy and safety of combining TXA and aspirin in postoperative management following TKA.
Basic objectives2
Efficacy
Basic objectives -Others
Trial characteristics_1
Trial characteristics_2
Developmental phase
Assessment
Primary outcomes
Incidence of lower limb deep vein thrombosis (DVT) at 3 weeks after total knee arthroplasty, assessed by duplex ultrasonography
Key secondary outcomes
Serial changes in D-dimer, hemoglobin, and interleukin-6 (IL-6)
(preoperative, postoperative days 1, 3, 7, 14, and 21)
Knee circumference (swelling)
(postoperative days 1, 3, 7, and 14)
Subcutaneous ecchymosis score
(postoperative days 1, 7, and 14)
Pain visual analog scale (VAS)
(postoperative days 1, 7, and 14)
Knee range of motion (ROM)
(postoperative days 1, 7, and 14)
Postoperative complications including infection
Detailed ultrasonographic findings of thrombi (location and characteristics)
(as secondary descriptive outcomes)
Base
Study type
Interventional
Study design
Basic design
Parallel
Randomization
Randomized
Randomization unit
Individual
Blinding
Double blind -all involved are blinded
Control
Placebo
Stratification
YES
Dynamic allocation
YES
Institution consideration
Institution is considered as a block.
Blocking
YES
Concealment
Numbered container method
Intervention
No. of arms
2
Purpose of intervention
Treatment
Type of intervention
| Medicine |
Interventions/Control_1
Postoperative oral tranexamic acid for 3 weeks combined with low-dose aspirin 100 mg/day for 3 weeks after total knee arthroplasty.
Interventions/Control_2
Postoperative oral tranexamic acid for 3 weeks combined with a placebo tablet (lactose) for 3 weeks after total knee arthroplasty.
Interventions/Control_3
Interventions/Control_4
Interventions/Control_5
Interventions/Control_6
Interventions/Control_7
Interventions/Control_8
Interventions/Control_9
Interventions/Control_10
Eligibility
Age-lower limit
| 50 | years-old | <= |
Age-upper limit
| 89 | years-old | >= |
Gender
Male and Female
Key inclusion criteria
Willingness to participate in a 3 week postoperative medication protocol and ability to provide written informed consent.
Key exclusion criteria
Patients with bilateral total knee arthroplasty (TKA).
Patients with contraindications to tranexamic acid (TXA) or aspirin, including peptic ulcer disease, severe renal impairment, or bleeding tendency.
Patients who are unable to provide written informed consent.
Patients deemed unsuitable for study participation by the principal investigator, including those with severe renal or hepatic dysfunction.
Target sample size
110
Research contact person
Name of lead principal investigator
| 1st name | Yoshinori |
| Middle name | |
| Last name | Mikashima |
Organization
Takagi Hospital
Division name
Oume Knee Surgery Center
Zip code
198-0021
Address
Imadera 5-18-19, Oume City, Tokyo
TEL
0428315255
ymikashima2007@yahoo.co.jp
Public contact
Name of contact person
| 1st name | Yoshinori |
| Middle name | |
| Last name | Mikashima |
Organization
Takagi Hospital
Division name
Oume Knee Surgery Center
Zip code
198-0021
Address
Imadera 5-18-19, Oume City, Tokyo
TEL
0428315255
Homepage URL
ymikashima2007@yahoo.co.jp
Sponsor or person
Institute
Takagi Hospital
Institute
Department
Personal name
Funding Source
Organization
self funded
Organization
Division
Category of Funding Organization
Self funding
Nationality of Funding Organization
Other related organizations
Co-sponsor
Name of secondary funder(s)
IRB Contact (For public release)
Organization
Takagi Hospital Ethics Committee
Address
Imadera 5-18-19, Oume City, Tokyo
Tel
0428315255
yamazaki@takagi-hp.or.jp
Secondary IDs
Secondary IDs
NO
Study ID_1
Org. issuing International ID_1
Study ID_2
Org. issuing International ID_2
IND to MHLW
Institutions
Institutions
Other administrative information
Date of disclosure of the study information
| 2026 | Year | 09 | Month | 04 | Day |
Related information
URL releasing protocol
Publication of results
Unpublished
Result
URL related to results and publications
Number of participants that the trial has enrolled
Results
Results date posted
Results Delayed
Results Delay Reason
Date of the first journal publication of results
Baseline Characteristics
Participant flow
Adverse events
Outcome measures
Plan to share IPD
IPD sharing Plan description
Progress
Recruitment status
Preinitiation
Date of protocol fixation
| 2026 | Year | 06 | Month | 27 | Day |
Date of IRB
| 2026 | Year | 06 | Month | 26 | Day |
Anticipated trial start date
| 2026 | Year | 09 | Month | 04 | Day |
Last follow-up date
| 2027 | Year | 10 | Month | 31 | Day |
Date of closure to data entry
Date trial data considered complete
Date analysis concluded
Other
Other related information
Management information
Registered date
| 2026 | Year | 06 | Month | 27 | Day |
Last modified on
| 2026 | Year | 06 | Month | 27 | Day |
Link to view the page
Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000071034
