Total Knee AnthroplastyACBNCT07595471
Proximal Spread in Adductor Canal Block(ACB)
A study testing Comparison of Proximal Adductor Canal Block and Comparison True Distal Adductor Canal Block. in people with Total Knee Anthroplasty and Postoperative Pain, run by Ankara Etlik City Hospital at 1 site in Turkey (Türkiye).
Trial summary
This prospective, randomized clinical study is designed to evaluate the effects of two different injection levels of adductor canal block (ACB) on the proximal spread of local anesthetic and clinical outcomes in patients undergoing total knee arthroplasty. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Total Knee Anthroplasty, Postoperative Pain
- What is being tested?
- Comparison of Proximal Adductor Canal Block and Comparison True Distal Adductor Canal Block.
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 68 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 7 Apr 2026to 1 Jun 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- * Patients aged > 18 years.
- ASA physical status classification I-III.
- Patients scheduled for elective, unilateral total knee arthroplasty (TKA).
- Planned administration of spinal anesthesia.
- Ability to provide written informed consent.
- Exclusion Criteria:Scheduled for bilateral knee arthroplasty.
Show all 12Show fewer
- Known hypersensitivity or allergy to local anesthetics.
- History of chronic pain syndrome or regular opioid consumption.
- Presence of peripheral neuropathy or neurological disorders affecting the femoral nerve.
- Coagulopathy or ongoing anticoagulant therapy.
- Active infection at the site of injection.
- Inability or refusal to provide written informed consent.
Who cannot join
None listed.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Impact of Injection Level on the Proximal Spread of Local Anesthetic and Clinical Outcomes in Adductor Canal Block
This prospective, randomized clinical study is designed to evaluate the effects of two different injection levels of adductor canal block (ACB) on the proximal spread of local anesthetic and clinical outcomes in patients undergoing total knee arthroplasty. The study will be conducted at Ankara Etlik City Hospital and will include a total of 68 patients. All cases are limited to unilateral elective knee replacement surgeries performed under spinal anesthesia. In this study, the comparison will be based on the application of adductor canal block at two distinct injection levels. In both groups, blocks will be performed under ultrasound (USG) guidance using the same technical principles and standardized conditions; in the first group, the block will be administered at the level where the vasto-adductor membrane is first visualized, while in the second group, it will be performed at the level where the adductor longus ends. The type, concentration, and volume of local anesthetic used in both groups will be standardized as 20 mL of 0.25% bupivacaine. The groups will be compared in terms of the proximal spread of the local anesthetic based on the injection level, the area of spread at the apex of the iliopectineal fossa, the involvement of the femoral nerve, the incidence of postoperative falls, and analgesic consumption.
Read the detailed description
This prospective, randomized clinical trial is designed to evaluate the effects of two distinct injection levels of ultrasound-guided adductor canal block (ACB) on the proximal spread of local anesthetic and clinical outcomes in patients undergoing total knee arthroplasty (TKA). The study will be conducted at Ankara Etlik City Hospital with a total of 68 patients. All cases are limited to unilateral elective knee replacement surgeries performed under spinal anesthesia. Inclusion and Exclusion Criteria Inclusion criteria are defined as patients aged 18 years and older, with an ASA (American Society of Anesthesiologists) physical status of I-III, scheduled for elective unilateral TKA under spinal anesthesia. Exclusion criteria include patients scheduled for bilateral knee arthroplasty, known allergy to local anesthetics, chronic pain syndromes or regular opioid use, peripheral neuropathy or neurological diseases affecting femoral nerve function, coagulopathy or use of anticoagulant therapy, infection at the injection site, and patients unable to provide written informed consent. Randomization and Intervention Patients will be randomized into two groups using the sealed envelope method. In Group 1, the ACB will be performed under ultrasound (USG) guidance at the level where the vasto-adductor membrane (VAM) is first visualized. In Group 2, the block will be performed at the level where the adductor longus muscle ends. All blocks will be administered by experienced anesthesiologists using a standardized dose of 20 mL 0.25% bupivacaine. Clinicians performing the block will not be involved in the postoperative data collection process. Procedure and Monitoring All patients will undergo standard monitoring, including electrocardiography (EKG), non-invasive arterial blood pressure, and peripheral oxygen saturation (SpO_2). Following the administration of spinal anesthesia according to clinical protocols, the ACB will be performed under USG guidance based on the randomization results. Standard care will be provided throughout the surgical and anesthetic management, and perioperative data will be recorded. Outcome Measures and Evaluation Following the block, the spread of the local anesthetic will be evaluated in real-time using ultrasound. The distance between the injection point and the highest proximal point of the anesthetic spread will be measured in centimeters. Additionally, the spread area of the local anesthetic at the level of the apex of the iliopectineal fossa will be recorded using the planimetric measurement tools of the USG device. The reach of the local anesthetic to the femoral nerve will also be assessed via USG. Postoperatively, patients will follow standard clinical monitoring. Motor block will be evaluated based on the incidence of postoperative falls (yes/no). Sensory block efficacy will be assessed through total analgesic consumption recorded within the first 24 hours postoperatively. All collected data will be recorded for statistical analysis and compared based on the injection levels.
- Conditions
- Total Knee Anthroplasty, Postoperative Pain
- Being tested
- Comparison of Proximal Adductor Canal Block, Comparison True Distal Adductor Canal Block.
- Keywords
- tka, adductor canal, block
- Medical subject headings
- Pain, Postoperative, Bites and Stings
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Comparison of Proximal Adductor Canal BlockDrug
In this study, patients were evaluated using two distinct approaches based on the evolution of anatomical definitions in recent literature: the proximal application, traditionally referred to as the adductor canal block but now more accurately defined as the 'Femoral Triangle Block' in current publications,
Comparison True Distal Adductor Canal Block.Drug
In this study, patients were evaluated using two distinct approaches based on the evolution of anatomical definitions in recent literature: the proximal application, traditionally referred to as the adductor canal block but now more accurately defined as the true 'Distal Adductor Canal Block' performed in accordance with contemporary anatomical criteria."
| Study group | Role | What they receive |
|---|---|---|
| Group 1: ACB at the proximal vasto-adductor membrane level (20 mL 0.25% bupivacaine) | Active comparator | Group 1: Patients receiving ultrasound-guided adductor canal block with 20 mL of 0.25% bupivacaine at the level where the vasto-adductor membrane is first visualized. Receives: Drug: Comparison of Proximal Adductor Canal Block |
| Group 2: Level of the end of the adductor longus | Active comparator | Group 2: Patients receiving ultrasound-guided adductor canal block with 20 mL of 0.25% bupivacaine at the level where the adductor longus muscle ends. Receives: Drug: Comparison True Distal Adductor Canal Block. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proximal spread of local anesthetic
The primary objective of this study is to compare the proximal spread of local anesthetic following ultrasound-guided adductor canal block performed at two distinct injection levels. In the first group, the injection will be administered at the level where the vastoadductor membrane is first visualized ultrasonographically in the proximal region. In the second group, the injection will be performed at the level where the adductor magnus and sartorius muscles first intersect.In both patient groups, the area of local anesthetic spread at the apex of the iliopectineal fossa will be measured in $cm^2$ using ultrasonography. Additionally, the distance between the needle insertion point (injection level) and the apex of the iliopectineal fossa, as well as the distance from the needle insertion point to the most proximal point where the local anesthetic is ultrasonographically visualized, will be recorded in cm.
Measured: The first postoperative hour
Secondary outcomes (2)
Pain Scores (Numeric Rating Scale)
Evaluation of NRS(Numeric Rating Scale) scores at the 6th and 24th postoperative hours.The Numerical Rating Scale (NRS) is a common subjective clinical tool that requires patients to quantify their pain intensity on a scale ranging from 0 to 10
Measured: post-op hours 6 and 24
Assessment of Motor Block
Motor block and falls were evaluated at the 24th hour.Ambulation was assessed within the first 24 hours postoperatively. Successful ambulation was defined as the ability to walk without falling; patients who failed to ambulate or suffered a fall during the attempt were categorized as 'treatment failure'.
Measured: Postoperative 24th hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 May 2026
- Study start7 Apr 2026
- Primary completion30 May 2026 (estimated)
- Study completion1 Jun 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Total Knee AnthroplastyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 68 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ankara Etlik City Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Müge Çakırca, Ankara Etlik City Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07595471
- Sponsor's protocol ID
- 2024-KAEK-40
- Acronym
- ACB
- Status last verified
- May 2026
- First submitted
- 7 Apr 2026
- Last updated
- 19 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Nair A, Dolan J, Tanner KE, Kerr CM, Jones B, Pollock PJ, Kellett CF. Ultrasound-guided adductor canal block: a cadaver study investigating the effect of a thigh tourniquet. Br J Anaesth. 2018 Oct;121(4):890-898. doi: 10.1016/j.bja.2018.04.044. Epub 2018 Jun 18.
PubMed 30236251
Study at a glance
From the registry record, last updated by the sponsor on 19 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Injection Level on the Proximal Spread of Local Anesthetic and Clinical Outcomes in Adductor Canal Block
- ClinicalTrials.gov ID
- NCT07595471
- Acronym / sponsor ID
- ACB / 2024-KAEK-40
- Conditions
- Total Knee Anthroplasty, Postoperative Pain
- Keywords
- tka, adductor canal, block
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 68 participants (estimated)
- Lead sponsor
- Ankara Etlik City HospitalOther government
- Study start
- 7 Apr 2026 (actual)
- Primary completion
- 30 May 2026 (estimated)
- Study completion
- 1 Jun 2026 (estimated)
- First posted
- 19 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This prospective, randomized clinical study is designed to evaluate the effects of two different injection levels of adductor canal block (ACB) on the proximal spread of local anesthetic and clinical outcomes in patients undergoing total knee arthroplasty. The study will be conducted at Ankara Etlik City Hospital and will include a total of 68 patients. All cases are limited to unilateral elective knee replacement surgeries performed under spinal anesthesia. In this study, the comparison will be based on the application of adductor canal block at two distinct injection levels. In both groups, blocks will be performed under ultrasound (USG) guidance using the same technical principles and standardized conditions; in the first group, the block will be administered at the level where the vasto-adductor membrane is first visualized, while in the second group, it will be performed at the level where the adductor longus ends. The type, concentration, and volume of local anesthetic used in both groups will be standardized as 20 mL of 0.25% bupivacaine. The groups will be compared in terms of the proximal spread of the local anesthetic based on the injection level, the area of spread at the apex of the iliopectineal fossa, the involvement of the femoral nerve, the incidence of postoperative falls, and analgesic consumption.
Detailed description
This prospective, randomized clinical trial is designed to evaluate the effects of two distinct injection levels of ultrasound-guided adductor canal block (ACB) on the proximal spread of local anesthetic and clinical outcomes in patients undergoing total knee arthroplasty (TKA). The study will be conducted at Ankara Etlik City Hospital with a total of 68 patients. All cases are limited to unilateral elective knee replacement surgeries performed under spinal anesthesia. Inclusion and Exclusion Criteria Inclusion criteria are defined as patients aged 18 years and older, with an ASA (American Society of Anesthesiologists) physical status of I-III, scheduled for elective unilateral TKA under spinal anesthesia. Exclusion criteria include patients scheduled for bilateral knee arthroplasty, known allergy to local anesthetics, chronic pain syndromes or regular opioid use, peripheral neuropathy or neurological diseases affecting femoral nerve function, coagulopathy or use of anticoagulant therapy, infection at the injection site, and patients unable to provide written informed consent. Randomization and Intervention Patients will be randomized into two groups using the sealed envelope method. In Group 1, the ACB will be performed under ultrasound (USG) guidance at the level where the vasto-adductor membrane (VAM) is first visualized. In Group 2, the block will be performed at the level where the adductor longus muscle ends. All blocks will be administered by experienced anesthesiologists using a standardized dose of 20 mL 0.25% bupivacaine. Clinicians performing the block will not be involved in the postoperative data collection process. Procedure and Monitoring All patients will undergo standard monitoring, including electrocardiography (EKG), non-invasive arterial blood pressure, and peripheral oxygen saturation (SpO_2). Following the administration of spinal anesthesia according to clinical protocols, the ACB will be performed under USG guidance based on the randomization results. Standard care will be provided throughout the surgical and anesthetic management, and perioperative data will be recorded. Outcome Measures and Evaluation Following the block, the spread of the local anesthetic will be evaluated in real-time using ultrasound. The distance between the injection point and the highest proximal point of the anesthetic spread will be measured in centimeters. Additionally, the spread area of the local anesthetic at the level of the apex of the iliopectineal fossa will be recorded using the planimetric measurement tools of the USG device. The reach of the local anesthetic to the femoral nerve will also be assessed via USG. Postoperatively, patients will follow standard clinical monitoring. Motor block will be evaluated based on the incidence of postoperative falls (yes/no). Sensory block efficacy will be assessed through total analgesic consumption recorded within the first 24 hours postoperatively. All collected data will be recorded for statistical analysis and compared based on the injection levels.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Group 1: ACB at the proximal vasto-adductor membrane level (20 mL 0.25% bupivacaine) | Active comparator | Drug: Comparison of Proximal Adductor Canal BlockGroup 1: Patients receiving ultrasound-guided adductor canal block with 20 mL of 0.25% bupivacaine at the level where the vasto-adductor membrane is first visualized. |
| Group 2: Level of the end of the adductor longus | Active comparator | Drug: Comparison True Distal Adductor Canal Block.Group 2: Patients receiving ultrasound-guided adductor canal block with 20 mL of 0.25% bupivacaine at the level where the adductor longus muscle ends. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (12 listed)
- * Patients aged > 18 years.
- Exclusion Criteria:Scheduled for bilateral knee arthroplasty.
- Known hypersensitivity or allergy to local anesthetics.
- History of chronic pain syndrome or regular opioid consumption.
- Presence of peripheral neuropathy or neurological disorders affecting the femoral nerve.
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Comparison of Proximal Adductor Canal BlockIn this study, patients were evaluated using two distinct approaches based on the evolution of anatomical definitions in recent literature: the proximal application, traditionally referred to as the adductor canal block but now more accurately defined as the 'Femoral Triangle Block' in current publications, | Drug | Group 1: ACB at the proximal vasto-adductor membrane level (20 mL 0.25% bupivacaine) |
| Comparison True Distal Adductor Canal Block.In this study, patients were evaluated using two distinct approaches based on the evolution of anatomical definitions in recent literature: the proximal application, traditionally referred to as the adductor canal block but now more accurately defined as the true 'Distal Adductor Canal Block' performed in accordance with contemporary anatomical criteria." | Drug | Group 2: Level of the end of the adductor longus |
Primary outcome
Proximal spread of local anesthetic
Time frame: The first postoperative hour
The primary objective of this study is to compare the proximal spread of local anesthetic following ultrasound-guided adductor canal block performed at two distinct injection levels. In the first group, the injection will be administered at the level where the vastoadductor membrane is first visualized ultrasonographically in the proximal region. In the second group, the injection will be performed at the level where the adductor magnus and sartorius muscles first intersect.In both patient groups, the area of local anesthetic spread at the apex of the iliopectineal fossa will be measured in $cm^2$ using ultrasonography. Additionally, the distance between the needle insertion point (injection level) and the apex of the iliopectineal fossa, as well as the distance from the needle insertion point to the most proximal point where the local anesthetic is ultrasonographically visualized, will be recorded in cm.
2 secondary outcomes
Pain Scores (Numeric Rating Scale)
Time frame: post-op hours 6 and 24
Assessment of Motor Block
Time frame: Postoperative 24th hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 May 2026.
- Background: PubMed 30236251Nair A, Dolan J, Tanner KE, Kerr CM, Jones B, Pollock PJ, Kellett CF. Ultrasound-guided adductor canal block: a cadaver study investigating the effect of a thigh tourniquet. Br J Anaesth. 2018 Oct;121(4):890-898. doi: 10.1016/j.bja.2018.04.044. Epub 2018 Jun 18.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Comparison of Proximal Adductor Canal Block and Comparison True Distal Adductor Canal Block. in people with Total Knee Anthroplasty and Postoperative Pain, run by Ankara Etlik City Hospital at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 12 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 19 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proximal spread of local anesthetic (time frame: The first postoperative hour). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07595471, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 May 2026.