Postoperative Pain Following Knee ArthroplastyeDIPACKNCT07080892
The Effect of Distal Versus Proximal iPACK on Pain After Total Knee Arthroplasty
A study testing distal iPACK and proximal iPACK in people with Postoperative Pain Following Knee Arthroplasty, run by Comenius University at 1 site in Slovakia.
Trial summary
Total knee arthroplasty (TKA) often results in significant postoperative pain, which can hinder recovery despite advances in surgical and anesthetic techniques. Traditional pain management methods like femoral nerve blocks may impair motor function, delaying rehabilitation. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Postoperative Pain Following Knee Arthroplasty
- What is being tested?
- distal iPACK and proximal iPACK
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 120 participants
- Where
- 1 siteSlovakia
- Study dates
- 12 Feb 2025to 30 May 2027
- 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
- Age between 18 and 80 years
- Patients undergoing primary unilateral total knee arthroplasty (TKA) for osteoarthritis
- Ability to understand and sign informed consent
- American Society of Anesthesiologists (ASA) classification I-III
- Ability to cooperate and participate in postoperative pain assessments (e.g., VAS)
Who cannot join
- Refusal to participate or failure to sign informed consent
- Bilateral or revision TKA
- Partial or unicondylar knee replacement
- Severe knee deformity (flexion, varus, or valgus >30°)
- Diagnosis other than osteoarthritis (e.g., rheumatoid arthritis, septic arthritis, post-traumatic arthritis)
- Allergy to local anesthetics or any medications used in the study
Show all 12Show fewer
- Contraindications to regional anesthesia (e.g., infection at the injection site, coagulopathy, therapeutic anticoagulation)
- BMI > 40 kg/m²
- Severe renal impairment (KDIGO stage G4 or higher) or liver failure (Child-Pugh score ≥ 10)
- Prior surgery or vascular procedure on the femoral vessels of the operated limb
- Language barrier or inability to assess pain using the VAS
- Planned outpatient (same-day discharge) procedure
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Slovakia1 site, 1 recruiting
- Recruiting
1st Department of Anaesthesiology and Intensive Care Medicine
Bratislava, 82101
Andrej Dano, MD, +421911571616, danoandreas@gmail.com
Andrej Dano, MD
About this study
Official title: The Effect of Distal Versus Proximal Approach to the Interspace Between the Popliteal Artery and the Posterior Capsule of the Knee (iPACK) on Pain After Total Knee Arthroplasty
Total knee arthroplasty (TKA) often results in significant postoperative pain, which can hinder recovery despite advances in surgical and anesthetic techniques. Traditional pain management methods like femoral nerve blocks may impair motor function, delaying rehabilitation. The iPACK block, targeting the posterior knee without affecting motor control, offers a promising alternative. This study aims to compare the effectiveness of two iPACK block approaches-proximal (at the distal femoral shaft) and distal (between the femoral condyles)-in managing postoperative pain in TKA patients. In a double-blind, randomized controlled trial with 120 participants, pain scores, opioid use, and time to rescue analgesia will be assessed. The hypothesis is that the distal iPACK block provides superior pain relief, potentially improving patient outcomes and recovery.
Read the detailed description
Total knee arthroplasty (TKA) is one of the most frequently performed orthopedic procedures in modern medicine. Despite advancements in surgical techniques and perioperative care, postoperative pain management remains a significant challenge and a key factor influencing time to mobilization, patient satisfaction, and length of hospital stay. Commonly used analgesic techniques, such as femoral nerve blocks or epidural analgesia, while effective, can impair motor function and thus delay rehabilitation.
To minimize motor deficits while still providing effective pain relief, newer regional anesthesia techniques have been introduced into clinical practice. One such technique is the iPACK block (interspace between the popliteal artery and posterior capsule of the knee), which targets the posterior knee - an area often insufficiently covered by conventional nerve blocks. This method involves administering a local anesthetic into the space between the popliteal artery and the posterior capsule of the knee joint, offering analgesia without significant motor impairment.
Originally, the iPACK block was described as being performed at the level of the distal femoral shaft, several centimeters above the femoral condyles. Recently, however, a more distal variation of the technique has emerged, where the anesthetic is injected directly between the femoral condyles. This may provide more effective coverage of the posterior knee capsule's innervation. To date, there are no randomized trials that directly compare the efficacy of the distal and proximal iPACK approaches in terms of postoperative pain as the primary outcome.
Our aim is to conduct a prospective, randomized, placebo-controlled, double-blind clinical trial to compare the effectiveness of the distal and proximal iPACK blocks in patients undergoing TKA. A total of 120 patients will be enrolled and randomly assigned to one of two groups.
- In the proximal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the level of the distal femoral shaft (a straight portion of the femur without the condyles).
- In the distal iPACK group, the same volume and concentration of anesthetic will be injected at the most distal part of the thigh, between the femoral condyles.
All participants, regardless of group assignment, will also receive an adductor canal block with 20 ml of 0.25% levobupivacaine without adrenaline. In addition, all patients will receive standard analgesic therapy consisting of paracetamol (1 g IV every 8 hours) and diclofenac (75 mg IV every 12 hours). If necessary, rescue opioid doses will be available according to individual needs.
The efficacy of each approach will be assessed using several parameters: total opioid consumption within 24 hours and time to first opioid rescue dose, Visual Analogue Scale (VAS) both at rest and during active knee movement (up to 45 degrees) at 6, 12, and 24 hours postoperatively.
The hypothesis of our study is that the distal iPACK approach will provide more effective postoperative pain control compared to the original proximal technique. If confirmed, the findings could influence perioperative pain management protocols for TKA, support the broader adoption of the distal iPACK block in clinical practice, enhance patient comfort, reduce opioid use, promote earlier mobilization, and potentially shorten hospital stays.
- Being tested
- distal iPACK, proximal iPACK
- Keywords
- pain, postoperative pain, arthroplasty, peripheral nerve block, iPACK
- Medical subject headings
- Pain, Pain, Postoperative
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
distal iPACKProcedure or surgery
● In the distal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the most distal part of the thigh, between the femoral condyles.
proximal iPACKProcedure or surgery
● In the proximal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the level of the distal femoral shaft (a straight portion of the femur without the condyles).
| Study group | Role | What they receive |
|---|---|---|
| proximal iPACK group | Experimental | In the proximal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the level of the distal femoral shaft (a straight portion of the femur without the condyles). Receives: Procedure: proximal iPACK |
| distal iPACK group | Experimental | In the distal iPACK group, the participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the most distal part of the thigh, between the femoral condyles. Receives: Procedure: distal iPACK |
What is being measured
The primary outcome is the main question the study is designed to answer.
total opioids consumption
total opioids consumption calculated to MME (morphine milligrams equivalent)
Measured: from surgery until 24 hours after surgery
Secondary outcomes (7)
time to first opioid administration
time to first opioid administration time in hours to first opioid administration after operation.
Measured: up to 24 hours after surgery
Visual analog scale 6 (rest)
pain intensity will be measured using the Visual Analogue Scale at rest 6 hours postoperatively. The Visual Analogue Scale is a validated, 100-mm horizontal line used to measure pain intensity, ranging from "no pain" (0 mm) to "worst possible pain" (100 mm).
Measured: 6 hours postoperatively
Visual analog scale 12 (rest)
pain intensity will be measured using the Visual Analogue Scale at rest 12 hours postoperatively. The Visual Analogue Scale is a validated, 100-mm horizontal line used to measure pain intensity, ranging from "no pain" (0 mm) to "worst possible pain" (100 mm).
Measured: 12 hours postoperatively
Visual analog scale 24 (rest)
pain intensity will be measured using the Visual Analogue Scale at rest 24 hours postoperatively, The Visual Analogue Scale is a validated, 100-mm horizontal line used to measure pain intensity, ranging from "no pain" (0 mm) to "worst possible pain" (100 mm).
Measured: 24 hours postoperatively
Visual analog scale 6 (flexion)
pain intensity will be measured using the Visual Analogue Scale at 45° flexion in the knee 6 hours postoperatively. The Visual Analogue Scale is a validated, 100-mm horizontal line used to measure pain intensity, ranging from "no pain" (0 mm) to "worst possible pain" (100 mm).
Measured: 6 hours postoperatively
Visual analog scale 12 (flexion)
pain intensity will be measured using the Visual Analogue Scale at 45° flexion in the knee 12 hours postoperatively. The Visual Analogue Scale is a validated, 100-mm horizontal line used to measure pain intensity, ranging from "no pain" (0 mm) to "worst possible pain" (100 mm).
Measured: 12 hours postoperatively
Visual analog scale 24 (flexion)
pain intensity will be measured using the Visual Analogue Scale at 45° flexion in the knee 24 hours postoperatively. The Visual Analogue Scale is a validated, 100-mm horizontal line used to measure pain intensity, ranging from "no pain" (0 mm) to "worst possible pain" (100 mm).
Measured: 24 hours postoperatively
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Jul 2025
- Study start12 Feb 2025
- Primary completion31 Dec 2026 (estimated)
- Study completion30 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Postoperative Pain Following Knee ArthroplastyStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Comenius University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07080892
- Sponsor's protocol ID
- UNB/RU/052025
- Acronym
- eDIPACK
- Status last verified
- Feb 2026
- First submitted
- 15 Jul 2025
- Last updated
- 4 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Distal Versus Proximal Approach to the Interspace Between the Popliteal Artery and the Posterior Capsule of the Knee (iPACK) on Pain After Total Knee Arthroplasty
- ClinicalTrials.gov ID
- NCT07080892
- Acronym / sponsor ID
- eDIPACK / UNB/RU/052025
- Keywords
- pain, postoperative pain, arthroplasty, peripheral nerve block, iPACK
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 120 participants (estimated)
- Lead sponsor
- Comenius UniversityUniversity, hospital or other
- Study start
- 12 Feb 2025 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 30 May 2027 (estimated)
- First posted
- 23 Jul 2025 (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.
Total knee arthroplasty (TKA) often results in significant postoperative pain, which can hinder recovery despite advances in surgical and anesthetic techniques. Traditional pain management methods like femoral nerve blocks may impair motor function, delaying rehabilitation. The iPACK block, targeting the posterior knee without affecting motor control, offers a promising alternative. This study aims to compare the effectiveness of two iPACK block approaches-proximal (at the distal femoral shaft) and distal (between the femoral condyles)-in managing postoperative pain in TKA patients. In a double-blind, randomized controlled trial with 120 participants, pain scores, opioid use, and time to rescue analgesia will be assessed. The hypothesis is that the distal iPACK block provides superior pain relief, potentially improving patient outcomes and recovery.
Detailed description
Total knee arthroplasty (TKA) is one of the most frequently performed orthopedic procedures in modern medicine. Despite advancements in surgical techniques and perioperative care, postoperative pain management remains a significant challenge and a key factor influencing time to mobilization, patient satisfaction, and length of hospital stay. Commonly used analgesic techniques, such as femoral nerve blocks or epidural analgesia, while effective, can impair motor function and thus delay rehabilitation.
To minimize motor deficits while still providing effective pain relief, newer regional anesthesia techniques have been introduced into clinical practice. One such technique is the iPACK block (interspace between the popliteal artery and posterior capsule of the knee), which targets the posterior knee - an area often insufficiently covered by conventional nerve blocks. This method involves administering a local anesthetic into the space between the popliteal artery and the posterior capsule of the knee joint, offering analgesia without significant motor impairment.
Originally, the iPACK block was described as being performed at the level of the distal femoral shaft, several centimeters above the femoral condyles. Recently, however, a more distal variation of the technique has emerged, where the anesthetic is injected directly between the femoral condyles. This may provide more effective coverage of the posterior knee capsule's innervation. To date, there are no randomized trials that directly compare the efficacy of the distal and proximal iPACK approaches in terms of postoperative pain as the primary outcome.
Our aim is to conduct a prospective, randomized, placebo-controlled, double-blind clinical trial to compare the effectiveness of the distal and proximal iPACK blocks in patients undergoing TKA. A total of 120 patients will be enrolled and randomly assigned to one of two groups.
- In the proximal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the level of the distal femoral shaft (a straight portion of the femur without the condyles).
- In the distal iPACK group, the same volume and concentration of anesthetic will be injected at the most distal part of the thigh, between the femoral condyles.
All participants, regardless of group assignment, will also receive an adductor canal block with 20 ml of 0.25% levobupivacaine without adrenaline. In addition, all patients will receive standard analgesic therapy consisting of paracetamol (1 g IV every 8 hours) and diclofenac (75 mg IV every 12 hours). If necessary, rescue opioid doses will be available according to individual needs.
The efficacy of each approach will be assessed using several parameters: total opioid consumption within 24 hours and time to first opioid rescue dose, Visual Analogue Scale (VAS) both at rest and during active knee movement (up to 45 degrees) at 6, 12, and 24 hours postoperatively.
The hypothesis of our study is that the distal iPACK approach will provide more effective postoperative pain control compared to the original proximal technique. If confirmed, the findings could influence perioperative pain management protocols for TKA, support the broader adoption of the distal iPACK block in clinical practice, enhance patient comfort, reduce opioid use, promote earlier mobilization, and potentially shorten hospital stays.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| proximal iPACK group | Experimental | Procedure: proximal iPACKIn the proximal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the level of the distal femoral shaft (a straight portion of the femur without the condyles). |
| distal iPACK group | Experimental | Procedure: distal iPACKIn the distal iPACK group, the participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the most distal part of the thigh, between the femoral condyles. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Age between 18 and 80 years
- Patients undergoing primary unilateral total knee arthroplasty (TKA) for osteoarthritis
- Ability to understand and sign informed consent
- American Society of Anesthesiologists (ASA) classification I-III
- Ability to cooperate and participate in postoperative pain assessments (e.g., VAS)
Key exclusion criteria (12 listed)
- Refusal to participate or failure to sign informed consent
- Bilateral or revision TKA
- Partial or unicondylar knee replacement
- Severe knee deformity (flexion, varus, or valgus >30°)
- Diagnosis other than osteoarthritis (e.g., rheumatoid arthritis, septic arthritis, post-traumatic arthritis)
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 |
|---|---|---|
| distal iPACK● In the distal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the most distal part of the thigh, between the femoral condyles. | Procedure or surgery | distal iPACK group |
| proximal iPACK● In the proximal iPACK group, participants will receive 20 ml of 0.25% levobupivacaine with adrenaline (1:200,000), injected at the level of the distal femoral shaft (a straight portion of the femur without the condyles). | Procedure or surgery | proximal iPACK group |
Primary outcome
total opioids consumption
Time frame: from surgery until 24 hours after surgery
total opioids consumption calculated to MME (morphine milligrams equivalent)
7 secondary outcomes
time to first opioid administration
Time frame: up to 24 hours after surgery
Visual analog scale 6 (rest)
Time frame: 6 hours postoperatively
Visual analog scale 12 (rest)
Time frame: 12 hours postoperatively
Visual analog scale 24 (rest)
Time frame: 24 hours postoperatively
Visual analog scale 6 (flexion)
Time frame: 6 hours postoperatively
Visual analog scale 12 (flexion)
Time frame: 12 hours postoperatively
Visual analog scale 24 (flexion)
Time frame: 24 hours postoperatively
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 4 Feb 2026.
- 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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing distal iPACK and proximal iPACK in people with Postoperative Pain Following Knee Arthroplasty, run by Comenius University at 1 site in Slovakia.
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 5 inclusion and 12 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: looking for participants now, as of the sponsor's last update on 4 Feb 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 Slovakia. 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?
Contact Andrej Dano, MD (+421911571616, danoandreas@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
total opioids consumption (time frame: from surgery until 24 hours after surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 4 Feb 2026.