Comparing nerve block methods with ropivacaine and epinephrine for pain relief in patients undergoing total knee replacement surgery for knee osteoarthritis

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What is this study about?

This study involves patients who are having surgery to replace their knee joint, a procedure called total knee replacement, which is done to treat knee osteoarthritis. Knee osteoarthritis is a condition where the protective cartilage in the knee wears down over time, causing pain and stiffness. The study will use different types of nerve blocks, which are injections given near nerves to reduce pain after surgery. The medications being used are ropivacaine hydrochloride, which is a local pain-relieving medicine that numbs the area, and epinephrine, which is a substance that helps the pain medicine work longer. These medications will be given through injections near the nerves around the knee.

The purpose of the study is to compare two different methods of blocking pain to see which one works better for patients after knee replacement surgery. One method involves blocking the genicular nerves, which are small nerves around the knee joint. The other method combines two types of blocks: one called the adductor canal block, which numbs nerves in a passage on the inner side of the thigh, and another called the IPACK block, which stands for infiltration between the popliteal artery and the capsule of the knee, targeting the back of the knee. The study will measure pain levels using a scale where patients rate their pain from zero to ten, with zero being no pain and ten being the worst pain imaginable.

During the study, patients will receive one of these two pain-blocking methods before their knee replacement surgery. After the surgery, the study team will check how much pain patients feel at different times, including right after surgery, at twelve hours, at twenty-four hours during their first physical therapy session, and at forty-eight hours. The study will also look at how much additional pain medicine patients need, how well they can move their knee, and their overall recovery quality. The treatment with the nerve blocks happens once, on the day of surgery, and the total amount of medication given will not exceed seventy milligrams of ropivacaine hydrochloride and three hundred fifty micrograms of epinephrine.

1 Random assignment to treatment group

Upon joining the study, you will be randomly assigned to one of two groups. One group will receive genicular nerve blocks, which are injections that numb specific nerves around the knee. The other group will receive a combination of two different types of nerve blocks: an adductor canal block, which numbs nerves in the inner thigh area, and an IPACK block, which stands for infiltration between the popliteal artery and the capsule of the knee and numbs nerves at the back of the knee.

The assignment to either group will be done by chance, similar to flipping a coin, to ensure fairness in the study.

2 Receiving nerve block injections before surgery

Before your knee replacement surgery begins, you will receive nerve block injections based on the group you were assigned to. These injections contain medications to numb the area around your knee and help manage pain after surgery.

The medications used in these injections are ropivacaine hydrochloride, which is a local anesthetic that numbs the nerves, and epinephrine, which helps the numbing medication last longer. Both medications will be injected around the nerves in your knee area.

The specific dosage, frequency, and duration of these medications have not been provided in the study information.

3 Undergoing total knee replacement surgery

After receiving the nerve block injections, you will undergo your planned total knee replacement surgery. This is a procedure where damaged parts of your knee joint are replaced with artificial components.

The surgery will proceed as planned by your surgeon.

4 Pain assessment immediately after surgery

Immediately after your surgery (at 0 hours), your pain level will be assessed using the Numerical Rating Scale, which is a scale from 0 to 10 where 0 means no pain and 10 means the worst pain imaginable.

You will be asked to rate your pain level at this time.

5 Pain assessment at 12 hours after surgery

Twelve hours after your surgery, your pain level will be assessed again using the Numerical Rating Scale.

You will be asked to rate your pain level at this time.

6 First physiotherapy session and pain assessment at 24 hours

At 24 hours after your surgery, you will have your first physiotherapy session. Physiotherapy involves exercises and movements designed to help your knee recover and regain function.

During this session, your pain level will be assessed using the Numerical Rating Scale. This is the main measurement point for comparing the effectiveness of the different nerve block techniques.

Your ability to move your knee will also be measured. This includes both active range of motion, which is how far you can move your knee on your own, and passive range of motion, which is how far your knee can be moved with assistance.

The amount of pain medication you have used, specifically opioids (strong pain relievers), will be recorded and converted to morphine equivalents for comparison purposes.

7 Pain assessment at 48 hours after surgery

At 48 hours (two days) after your surgery, your pain level will be assessed once more using the Numerical Rating Scale.

You will be asked to rate your pain level at this time.

8 Quality of recovery assessment

At some point during your recovery, you will be asked to complete the Quality of Recovery 15 questionnaire. This is a set of 15 questions that assess how well you are recovering after surgery, including aspects like pain, physical comfort, emotional state, and ability to perform daily activities.

The specific timing for completing this questionnaire has not been provided in the study information.

Who Can Join the Study?

You must be scheduled to have a primary total knee arthroplasty, which is a surgery to replace your knee joint for the first time
You must agree to take part in the study by giving your consent
Your surgeon must also agree that you can participate in the study
You must have an ASA physical status of I, II, or III, which is a way doctors classify your overall health condition before surgery, ranging from healthy to having moderate medical problems
Your BMI must be between 18 and 40, which stands for Body Mass Index, a measurement that uses your height and weight to estimate your body fat
You must be an adult or elderly person
Both men and women can participate in this study

Who Cannot Join the Study?

Pregnancy or breastfeeding: Women who are pregnant or nursing a baby cannot participate in this study.
Allergy to local anesthetics: Patients who have had allergic reactions to numbing medications (drugs used to block pain during procedures) cannot join.
Infection at injection site: If there is an infection in the area where the nerve block injection would be given, the patient cannot participate.
Bleeding disorders: Patients with conditions that cause problems with blood clotting or who are taking blood-thinning medications that cannot be stopped safely are excluded.
Severe heart disease: Patients with serious heart conditions that are not well controlled cannot take part.
Nerve damage in the leg: Pre-existing damage to nerves in the leg being operated on may prevent participation.
Inability to communicate pain levels: Patients who cannot understand or communicate their pain level using a number scale cannot participate.
Chronic pain requiring daily opioids: Patients who regularly take strong pain medications (opioids) for long-term pain conditions before surgery are excluded.
Previous knee surgery on same knee: Patients who have already had a knee replacement or major surgery on the same knee may not be eligible.
Refusal of regional anesthesia: Patients who do not want to receive nerve blocks (injections that numb specific areas) cannot participate.
Psychiatric conditions affecting consent: Patients with mental health conditions that prevent them from understanding and agreeing to participate are excluded.

Where you can join this trial?

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Other Sites

Site Name	City	Country	Status
Hospital Clinic De Barcelona	Barcelona	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not yet recruiting	01.01.2026

Trial locations

Investigated drugs:

Adductor canal block is a pain relief procedure where medication is injected near nerves in the thigh to numb the area around the knee. This helps reduce pain after knee surgery while still allowing you to move your leg.

IPACK block (infiltration between the popliteal artery and the capsule of the knee) is a pain relief procedure where medication is injected in the back of the knee between a major blood vessel and the knee joint covering. This helps control pain in the back part of the knee after surgery.

Genicular nerve block is a pain relief procedure where medication is injected near specific nerves that supply sensation to the knee joint. This targets pain directly at the knee joint itself after surgery.

Knee Osteoarthritis – Knee osteoarthritis is a condition where the protective cartilage that cushions the ends of bones in the knee joint gradually breaks down over time. As the cartilage wears away, the bones may begin to rub against each other, causing pain and stiffness. The condition typically develops slowly and worsens over years. People with knee osteoarthritis often experience pain during movement, swelling in the joint, and reduced flexibility. The knee may feel stiff, especially after periods of rest or in the morning. As the disease progresses, daily activities such as walking, climbing stairs, or standing up from a seated position become increasingly difficult.

Trial ID:

2025-523071-34-00

Protocol code:

ADIPGEN

Trial Phase:

Therapeutic confirmatory (Phase III)

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Comparing nerve block methods with ropivacaine and epinephrine for pain relief in patients undergoing total knee replacement surgery for knee osteoarthritis

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?