Nerve Block Techniques for Postoperative Pain from Knee Surgery

Overseen By Julie Desroches, Ph. D

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Centre hospitalier de l'Université de Montréal (CHUM)

Must not be taking: Opioids

Disqualifiers: Pregnancy, Under 50 kg, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 1

Duration: 1 day

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new method for managing pain after knee replacement surgery. It examines whether adding an extra nerve block, which numbs specific nerves, can enhance pain relief and help patients move sooner post-surgery. The researchers compare the current standard nerve block with a combination approach that includes the new Femoral Triangle Block (FTB). Ideal participants are adults undergoing a first-time knee replacement and not on heavy daily pain medication. As an unphased trial, this study allows patients to contribute to innovative pain management strategies that could improve recovery experiences for future knee replacement patients.

Will I have to stop taking my current medications?

The trial protocol does not specify whether you need to stop taking your current medications. However, if you are taking more than 60 mg of morphine daily for chronic pain, you would not be eligible to participate.

What prior data suggests that these nerve block techniques are safe for postoperative pain management?

Research has shown that nerve blocks like the femoral triangle block (FTB) and the para-sartorial compartments block (PACS) are generally well-tolerated during knee surgery. These methods effectively manage pain without significantly affecting movement. The PACS block targets additional nerve areas not reached by the FTB alone, potentially improving pain relief.

When combined with the IPACK block, which focuses on the back of the knee, these techniques aim to provide comprehensive pain management. Previous studies reported few side effects. Medications used, such as ropivacaine, are usually safe, with only mild side effects like temporary numbness or soreness at the injection site. This combination of nerve blocks is considered safe based on current research and helps patients recover faster with better pain control. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores innovative nerve block techniques for managing postoperative pain after knee surgery. Unlike the standard femoral triangle block (FTB) combined with IPACK, which is commonly used now, the experimental approach adds two additional ropivacaine injections in the subsartorial and suprasartorial compartments. This multi-site injection strategy aims to enhance pain relief by targeting more areas involved in knee sensation. By potentially offering more comprehensive pain management, these techniques could improve patient comfort and recovery time following knee surgery.

What evidence suggests that this trial's nerve block techniques could be effective for postoperative pain from knee surgery?

In this trial, one group of participants will receive a combination of the femoral triangle block (FTB) with the IPACK block. Previous studies have shown that this combination effectively relieves early pain after knee surgery and improves quadriceps muscle function. The IPACK block targets the sensory nerves behind the knee to ease pain in that area, while the FTB reduces pain without affecting leg movement. Another group will receive an additional para-sartorial compartments block, which research indicates can further improve pain relief by covering additional nerve areas not addressed by the FTB alone. Together, these blocks aim to offer better pain control, helping patients move more easily after surgery. This approach has been highlighted for its potential to enhance pain management while preserving leg strength. ^{1 2 3 6 7}

Who Is on the Research Team?

Maxim Roy, MD, FRCPC

Principal Investigator

Centre hospitalier de l'Université de Montréal (CHUM)

Are You a Good Fit for This Trial?

This trial is for adults over 18 needing a primary total knee replacement, with an 'American Society of Anesthesiologists' classification of 1 to 3. It's not for those who can't consent or communicate with the team, don't understand instructions, are pregnant, weigh under 50 kg, have contraindications to nerve blocks or take daily pain meds equivalent to more than 60 mg of morphine.

Inclusion Criteria

Your health condition falls within the categories 1 to 3 according to the American Society of Anesthesiologists classification.

Exclusion Criteria

I take more than 60 mg of morphine daily for chronic pain.

I weigh less than 50 kg.

I cannot have a peripheral nerve block due to health reasons.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive nerve blocks including the femoral triangle block and potentially additional blocks for postoperative analgesia after knee replacement surgery

1 day

1 visit (in-person)

Immediate Postoperative Monitoring

Participants are monitored for pain levels, complications, and recovery quality within the first 24 hours after surgery

24 hours

Continuous monitoring

Follow-up

Participants are monitored for pain intensity, quality of recovery, and patient satisfaction up to 7 days after surgery

7 days

What Are the Treatments Tested in This Trial?

Interventions

• Femoral Triangle Block (FTB)
• Infiltration between Popliteal Artery and Capsule of the Knee Block (IPACK)
• Para-Sartorial Compartments (PACS) Block

Trial Overview The study tests if adding a para-sartorial compartments (PACS) block to the femoral triangle block (FTB) improves pain relief after knee replacement surgery. The PACS aims at blocking additional nerves that aren't covered by FTB alone and could enhance postoperative analgesia allowing earlier mobilization.

How Is the Trial Designed?

Group I: Para-Sartorial Compartment (PACS) Block + Femoral Triangle Block (FTB) + IPACK block Experimental Treatment 3 Interventions

In addition to the injection performed in the femoral triangle, two injections of 5 mL of 0.5% ropivacaine + epi 1:400 000 will be performed below the sartorius muscle (subsartorial compartment) and above the sartorius muscle (suprasartorial compartment). For all patients, an infiltration between popliteal artery and capsule of the knee block (IPACK) will be performed concomitantly, in order to block the sensory branches of the innervation posterior to the knee with 15 ml of ropivacaine 0.3% + epi 1:400 000.

Group II: Femoral Triangle Block (FTB) + IPACK block Active Control 2 Interventions

This block is currently the most used in practice and is considered a standard of care. It consists of a single injection of 15 ml of 0.5% ropivacaine + epi 1:400 000 under the sartorius muscle, lateral to the femoral artery, at the level of the apex of the femoral triangle For all patients, an infiltration between popliteal artery and capsule of the knee block (IPACK) will be performed concomitantly, in order to block the sensory branches of the innervation posterior to the knee with 15 ml of ropivacaine 0.3% + epi 1:400 000.

Who Is Running the Clinical Trial?

Centre hospitalier de l'Université de Montréal (CHUM)

Lead Sponsor

Trials

389

Recruited

143,000+

Published Research Related to This Trial

Femoral nerve block significantly improves postoperative pain management after outpatient anterior cruciate ligament repair, with patients receiving a sham block reporting higher pain scores and needing more intravenous analgesia.

Both 0.25% and 0.5% bupivacaine provided effective analgesia lasting approximately 23.2 and 25.7 hours, respectively, demonstrating that femoral nerve blocks can enhance recovery in the immediate postoperative period.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Femoral nerve block with 0.25% or 0.5% bupivacaine improves postoperative analgesia following outpatient arthroscopic anterior cruciate ligament repair. Mulroy, MF., Larkin, KL., Batra, MS., et al.[2022]

In a study of 78 patients undergoing total knee arthroplasty, the combination of an obturator nerve block (ONB) and a femoral triangle block (FTB) significantly reduced opioid consumption to just 2 mg in the first 24 hours, compared to 20 mg for FTB alone and 17 mg for local infiltration analgesia (LIA).

Patients receiving the combined ONB and FTB also experienced less pain, nausea, and vomiting, indicating improved postoperative comfort without negatively affecting their ability to ambulate.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Analgesic Effect of Obturator Nerve Block Added to a Femoral Triangle Block After Total Knee Arthroplasty: A Randomized Controlled Trial. Runge, C., Børglum, J., Jensen, JM., et al.[2019]

In a study of 80 patients undergoing total knee arthroplasty, combining an anterior femoral cutaneous nerve block (AFCNB) with a femoral triangle block (FTB) significantly reduced pain during movement 12 hours post-surgery compared to FTB alone, with a mean difference in pain scores of -2.02.

The AFCNB + FTB group also experienced lower incidence of surgical site pain and reduced morphine consumption within 48 hours postoperatively, while showing improved quadriceps muscle strength immediately after surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The analgesic efficacy of anterior femoral cutaneous nerve block in combination with femoral triangle block in total knee arthroplasty: a randomized controlled trial. Kampitak, W., Tanavalee, A., Tansatit, T., et al.[2022]

In a study of 100 patients undergoing total knee and hip replacement, the fascia iliaca compartment block (FIB) provided better pain control after the first six hours post-surgery compared to the femoral nerve block, as indicated by lower Visual Analogue Scale (VAS) scores at 24 hours.

While the femoral nerve block was more effective in reducing pain and analgesic consumption in the first 30 minutes, the FIB resulted in a higher quality of recovery, as measured by the QoR-40 questionnaire, 24 hours after surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of the efficacy of femoral nerve block and fascia iliaca compartment block in patients with total knee replacement. Kanadli, H., Dogru, S., Karaman, T., et al.[2019]

Femoral nerve block (FNB) resulted in significantly lower quadriceps strength at 6 hours postoperatively compared to femoral triangle block (FTB) and adductor canal block (ACB), but all groups showed no differences in strength at 24 and 48 hours, indicating that FNB may initially impair muscle strength without affecting long-term recovery.

FNB provided better pain control at 6, 24, and 48 hours post-surgery compared to FTB and ACB, while ACB required the highest cumulative opioid use, suggesting a trade-off between pain management and muscle strength preservation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Single-injection nerve blocks for total knee arthroplasty: femoral nerve block versus femoral triangle block versus adductor canal block-a randomized controlled double-blinded trial. de Arzuaga, CIS., Miguel, M., Biarnés, A., et al.[2023]

In a study of 44 patients undergoing total knee arthroplasty, the femoral triangle catheter (FTB-Cath) resulted in significantly better preservation of quadriceps strength compared to the femoral nerve block catheter (F-Cath) on postoperative day 2, with 77.3% of FTB-Cath patients scoring ≥4 on the Manual Muscle Test versus only 13.6% in the F-Cath group (p < 0.001).

Both techniques provided similar pain relief, indicating that the FTB-Cath is an effective alternative for regional analgesia that minimizes quadriceps weakness while maintaining effective pain management.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Femoral nerve inguinal approach versus proximal femoral triangle ap proach for continuous regional analgesia in active rehabilitation after total knee arthroplasty: A prospective, randomised study. Guilley, J., Besançon, I., Hivert, A., et al.[2022]

This meta-analysis of five randomized controlled trials involving 308 patients found no significant differences in pain control (measured by VAS scores) or opioid consumption between femoral nerve block (FNB) and fascia iliaca block (FIB) for postoperative pain management after total knee and hip arthroplasties.

Both FNB and FIB showed similar safety profiles, with no significant increase in complications such as nausea, vomiting, or pruritus, suggesting that either technique can be safely used for pain control in these surgeries.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Femoral nerve block versus fascia iliaca block for pain control in total knee and hip arthroplasty: A meta-analysis from randomized controlled trials. Wang, X., Sun, Y., Wang, L., et al.[2022]

In a study of 90 patients undergoing total knee arthroplasty, the combination of 0.1% ropivacaine with dexmedetomidine resulted in better preservation of quadriceps muscle strength compared to higher concentrations of ropivacaine, indicating a safer option for pain management post-surgery.

Patients receiving the dexmedetomidine and lower concentration ropivacaine also demonstrated improved walking ability, as measured by the Timed Up and Go test, without compromising pain control compared to higher doses of ropivacaine.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Effect Of Dexmedetomidine As Adjuvant To Ropivacaine 0.1% For Femoral Nerve Block On Strength Of Quadriceps Muscle In Patients Undergoing Total Knee Arthroplasty: A Double-Blinded Randomized Controlled Trial. Yang, X., Kang, W., Xiong, W., et al.[2022]

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/34039734/

Combination of femoral triangle block and infiltration ... Recently, the iPACK block (infiltration between the popliteal artery and the capsule of the posterior knee) has been described to relieve posterior knee pain.

2. clinicaltrials.gov clinicaltrials.gov/study/NCT05566561

Para-sartorial Compartment Block in Knee Surgery Parasartorial compartment block (PSKB); is based on the blockade of the branches of the saphenous nerve, the two largest sensory nerves from the femoral nerve ...

3. researchgate.net researchgate.net/publication/360395005_The_para-sartorial_compartments_PASC_block_a_new_approach_to_the_femoral_triangle_block_for_complete_analgesia_of_the_anterior_knee

The para‐sartorial compartments (PASC) block For posterior compartment pain relief, the infiltration between the popliteal artery and the knee capsule is the preferred approach.

4. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/35144303/

Comparison of Femoral Triangle Block in Combination with ... Combining FTB and IPACK significantly increased the quadriceps muscle in patients, together with relieving early pain and reducing the amount of anesthetic ...

5. journals.lww.com journals.lww.com/sjan/fulltext/2025/04000/fascial_plane_blocks_for_postoperative_pain.7.aspx

Fascial plane blocks for postoperative pain management... This narrative review evaluates the effectiveness and safety of motor-sparing fascial plane blocks for total knee replacement

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6547229/

Implementation of the IPACK (Infiltration between ... The Infiltration between the Popliteal Artery and Capsule of the Knee (IPACK) block is a new anesthesiologist- administered analgesic technique for ...

7. researchgate.net researchgate.net/publication/368362289_Para-sartorial_compartments_Pasc_block_for_knee_surgeries_a_report_of_five_cases

Para-sartorial compartments (Pasc) block for knee surgeries [5] Moreover, a recent study advocated blocking the intermediate femoral cutaneous nerve (IFCN) separately using triple injection ...