An interventional study of GENIVS block and Adductor Canal Block (ACB) Only in Arthroplasty, Replacement, Knee, Pain, Postoperative and Osteoarthritis, Knee, sponsored by Bakirkoy Dr. Sadi Konuk Research and Training Hospital. Not yet recruiting at 1 site in Turkey (Türkiye). Open to participants aged 55 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-10-28.
Sponsored by Bakirkoy Dr. Sadi Konuk Research and Training Hospital · Not applicable, Interventional, and Treatment
The goal of this clinical trial is to learn whether the ultrasound-guided GENIVS block is not worse than (non-inferior to) the adductor canal block in reducing opioid use after total knee arthroplasty performed under spinal anesthesia. The main question it aims to answer is:
- Is total opioid consumption (intravenous tramadol, mg) in the first 24 hours after surgery with the GENIVS block not clinically worse than with the adductor canal block?
Researchers will also compare pain scores, time to the first analgesic request, the need for rescue pain medication, mobilization (Timed Up and Go test and stair climbing), quality of recovery (QoR-15) and opioid-related side effects between the two groups.
Participants will:
Background: Total knee arthroplasty (TKA) causes severe postoperative pain that limits early physiotherapy and mobilization and prolongs hospital stay. Procedure-specific recommendations favor opioid-sparing multimodal analgesia that includes the adductor canal block (ACB), with opioids reserved for rescue. The ACB largely preserves quadriceps strength but does not cover the posterior knee capsule. The GENIVS (GENicular + iPACK + VastuS) block is a motor-sparing, ultrasound-guided periosteal plane block in which local anesthetic is deposited on the distal femoral periosteum and spreads circumferentially around the femur, aiming to block the genicular nerves, the nerve to vastus intermedius and the posterior capsular branches with a single injection. No randomized trial has compared the GENIVS block with the ACB.
Design: Single-center, prospective, randomized, double-blind, parallel-group non-inferiority trial at Bakirkoy Dr. Sadi Konuk Research and Training Hospital, Istanbul, Türkiye. The trial is registered before the first participant is enrolled.
Participants and randomization: Seventy-four patients aged 55-75 years (ASA physical status I-III) scheduled for elective, primary, unilateral TKA under spinal anesthesia will be randomized 1:1 to Group G (GENIVS block, n = 37) or Group A (ACB, n = 37). Before the study begins, a clinician outside the study team will generate the allocation list with Research Randomizer (www.randomizer.org) by drawing one set of 37 unique numbers from 1-74; these sequence numbers are allocated to Group G and the remaining 37 to Group A. The same clinician will prepare sequentially numbered, sealed, opaque envelopes. On the day of surgery, after eligibility is reconfirmed, envelopes are opened in sequence immediately before the block by an anesthesiologist who is involved neither in block performance nor in data collection, and the envelope number is recorded in the case report form.
Anesthesia and interventions: All patients receive standard monitoring, spinal anesthesia with 10-15 mg of 0.5% isobaric bupivacaine plus 10 µg fentanyl, and standardized sedation with intravenous midazolam 0.02 mg/kg. No periarticular or intra-articular local anesthetic infiltration is performed. At the end of surgery, while the patient is still under spinal anesthesia, an anesthesiologist with at least five years of regional anesthesia experience who is not involved in data collection performs the allocated ultrasound-guided block with 20 mL of 0.375% bupivacaine (75 mg). To maintain blinding, identical dressings are placed over both the GENIVS and the ACB needle-entry sites in every patient.
Postoperative analgesia: The time of PCA connection in the recovery unit is defined as hour 0. All patients receive intravenous tramadol PCA (4 mg/mL; 15 mg bolus; 20-minute lockout; no background infusion) for 72 hours, intravenous paracetamol 1 g every 6 hours (first dose at skin closure), rescue intravenous dexketoprofen 50 mg when the visual analog scale (VAS) score at rest is 4 or higher (at least 8 hours apart, maximum 150 mg/day), and intravenous ondansetron 4 mg for nausea or vomiting. No other analgesics or adjuvants are given.
Outcome assessment: All postoperative assessments are performed by investigators who are blinded to group allocation. VAS scores at rest and during active knee flexion are recorded at 2, 4, 8, 12 and 24 hours and, as exploratory outcomes, at 36, 48, 60 and 72 hours. Residual motor block from spinal anesthesia is assessed with the Bromage scale before each movement VAS. The Timed Up and Go test is performed at 24, 48 and 72 hours with a walker under physiotherapist supervision, stair climbing on postoperative day 2, the Turkish QoR-15 before surgery and at 24 hours, and the Opioid-Related Symptom Distress Scale at 24, 48 and 72 hours.
Sample size: Based on a reported mean 24-hour intravenous tramadol consumption of 262.9 ± 59.8 mg after ACB, assuming a common standard deviation of 80 mg, a non-inferiority margin of 65.7 mg (25% of the expected ACB consumption), a true difference of zero, one-sided α = 0.025 and 90% power, 33 evaluable patients per group are required. Thirty-seven patients per group (74 in total) will be enrolled to allow for 10% dropout.
Statistical analysis: The mean difference (GENIVS - ACB) in 24-hour opioid consumption is estimated with a two-sided 95% confidence interval; non-inferiority is concluded if the upper limit is below 65.7 mg in both the modified intention-to-treat and the per-protocol populations, and superiority is tested hierarchically thereafter. Secondary outcomes are compared with two-sided tests (Bonferroni correction for VAS time points, Kaplan-Meier and log-rank test for time to the first request, a linear mixed model with baseline as covariate for the Timed Up and Go test, and ANCOVA adjusted for baseline for QoR-15). Analyses are performed with IBM SPSS Statistics 32.0.
5,640 studies on the registry are indexed under Pain, Postoperative; 1,230 are open to participants now.
This study's planned enrollment of 74 is close to the median of 75 across 4,821 interventional studies indexed under Pain, Postoperative.
Browse Pain, Postoperative studies →Bakirkoy Dr. Sadi Konuk Research and Training Hospital is the lead sponsor of 122 studies on the registry; 14 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
At the end of total knee arthroplasty under spinal anesthesia, an ultrasound-guided single-injection GENIVS block is performed with 20 mL of 0.375% bupivacaine (75 mg). A dressing is also placed over the adductor canal site for blinding. Patients receive the standard postoperative analgesia protocol (intravenous tramadol PCA, intravenous paracetamol 1 g every 6 hours and rescue intravenous dexketoprofen) for 72 hours.
Procedure: GENIVS block
At the end of total knee arthroplasty under spinal anesthesia, an ultrasound-guided single-injection adductor canal block is performed with 20 mL of 0.375% bupivacaine (75 mg). A dressing is also placed over the GENIVS site for blinding. Patients receive the standard postoperative analgesia protocol (intravenous tramadol PCA, intravenous paracetamol 1 g every 6 hours and rescue intravenous dexketoprofen) for 72 hours.
Procedure: Adductor Canal Block (ACB) Only
Ultrasound-guided single-injection periosteal plane block. A linear probe is placed transversely on the medial distal thigh at or just distal to the apex of the femoral triangle and rotated about 45 degrees. The needle is advanced in-plane from medial to lateral until it contacts the anteromedial femoral periosteum beneath the vastus medialis. After bone contact is confirmed and the needle-tip position is checked with 1-2 mL of 5% dextrose, 20 mL of 0.375% bupivacaine (75 mg) is injected in 5-mL aliquots with intermittent aspiration, aiming for distal and circumferential periosteal spread.
Also known as: Genicular, iPACK and vastus (GENIVS) periosteal plane block
Ultrasound-guided single-injection adductor canal block at mid-thigh (midpoint between the inguinal ligament and the superior border of the patella). The needle is advanced in-plane from lateral to medial beneath the sartorius muscle next to the femoral artery. After the needle-tip position is checked with 1-2 mL of 5% dextrose, 20 mL of 0.375% bupivacaine (75 mg) is injected in 5-mL aliquots with intermittent aspiration so that it spreads around the artery.
Total opioid consumption in the first 24 hours
Total opioid consumption, measured as the cumulative intravenous tramadol dose (mg) recorded by the patient-controlled analgesia device from PCA connection (hour 0) to 24 hours.
Time frame: 0 to 24 hours after PCA connection
Pain at rest
Pain at rest on a 10-cm visual analog scale (0 = no pain, 10 = worst imaginable pain).
Time frame: 2, 4, 8, 12 and 24 hours after PCA connection
Pain during active knee flexion
Pain during active knee flexion on a 10-cm visual analog scale (0 = no pain, 10 = worst imaginable pain), measured after the spinal motor block has resolved (Bromage score 1).
Time frame: 2, 4, 8, 12 and 24 hours after PCA connection
Time to first analgesic request
Time (hours) from PCA connection to the first bolus request on the patient-controlled analgesia device.
Time frame: Up to 24 hours after PCA connection
Rescue analgesic requirement
Proportion of patients who receive rescue intravenous dexketoprofen (given when the VAS score at rest is 4 or higher) and the number of rescue doses.
Time frame: 0 to 24 hours after PCA connection
Timed Up and Go test
Time (seconds) to rise from a standard armchair, walk 3 meters, turn, walk back and sit down, performed with a walker under physiotherapist supervision. The proportion of patients unable to complete the test is also reported.
Time frame: 24, 48 and 72 hours after PCA connection
Stair climbing performance
Number of steps climbed in a single attempt without stopping on a standard staircase (step height about 17 cm, one handrail), under physiotherapist supervision.
Time frame: Postoperative day 2
Quality of recovery
Total score of the Turkish version of the Quality of Recovery-15 questionnaire (range 0-150; higher scores indicate better recovery).
Time frame: 24 hours after PCA connection
Late pain scores
Pain at rest and during active knee flexion on a 10-cm visual analog scale (0 = no pain, 10 = worst imaginable pain).
Time frame: 36, 48, 60 and 72 hours after PCA connection
Late opioid consumption
Intravenous tramadol consumption (mg) recorded by the patient-controlled analgesia device.
Time frame: 24 to 48 hours and 48 to 72 hours after PCA connection
Opioid-related side effects
Opioid-Related Symptom Distress Scale: presence, frequency, severity and distress of 12 symptoms during the previous 24 hours.
Time frame: 24, 48 and 72 hours after PCA connection
Plan to share: No — Individual participant data will not be shared. The informed consent form and the ethics committee approval do not cover sharing individual-level data with other researchers, and the data are protected under the Turkish Personal Data Protection Law (Law No. 6698). Results will be reported only in aggregate form
Start is estimated for Dec 2026; primary completion for Jun 2027, 6 months later.
Of 2,089 non-industry interventional studies with no phase under Pain, Postoperative, half reached primary completion within 11 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 23. This study's planned 6 months is below that.
Counting every sponsor, half of 2,102 studies reached it within 11 months; a quarter within 6 and three quarters within 23.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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