Distal versus proximal iPACK for pain control after total knee replacement

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

This test compares distal and proximal iPACK nerve blocks to see which provides better pain relief for adults having a total knee replacement.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 120 (estimated)
• Ages: 18 Years to 80 Years
• Sex: All
• Sponsor: Comenius University (other)
• Locations: 1 site (Bratislava)
• Trial ID: NCT07080892 on ClinicalTrials.gov

What this trial studies

In a double-blind, randomized controlled design, 120 adults undergoing primary unilateral total knee arthroplasty for osteoarthritis will receive either a distal iPACK (between the femoral condyles) or a proximal iPACK (at the distal femoral shaft) as part of perioperative analgesia. Pain scores at rest and on movement, opioid consumption, and time to first rescue analgesia will be recorded, together with measures of motor function and recovery. The iPACK targets the posterior knee capsule to provide analgesia while sparing major motor nerves, and investigators hypothesize the distal injection may better cover posterior innervation. Standardized anesthesia and postoperative care protocols will be used and patients with contraindications to regional anesthesia or non-osteoarthritis diagnoses are excluded.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18–80 scheduled for primary unilateral total knee arthroplasty for osteoarthritis, classified ASA I–III, who can give informed consent and participate in postoperative pain assessments.

Not a fit: Those having revision or bilateral knee replacements, non-osteoarthritis diagnoses, severe knee deformity, contraindications to regional anesthesia, BMI over 40, or significant renal or liver failure are unlikely to qualify and may not benefit from the results.

Why it matters

Potential benefit: If the distal iPACK proves superior, patients could experience less postoperative pain and opioid use while preserving leg strength and speeding rehabilitation.

How similar studies have performed: Observational and anatomical studies suggest iPACK provides posterior knee analgesia without major motor blockade, but randomized comparisons of distal versus proximal approaches are currently lacking.

Eligibility criteria

Inclusion Criteria:

* 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)

Exclusion Criteria:

* 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
* 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

Where this trial is running

Bratislava

• 1st Department of Anaesthesiology and Intensive Care Medicine — Bratislava, Slovakia (RECRUITING)

Study contacts

• Study coordinator: Andrej Dano, MD

Conditions: Postoperative Pain Following Knee Arthroplasty, pain, postoperative pain, arthroplasty, peripheral nerve block, iPACK