An interventional study of Ultrasound-Guided Adductor Canal Block and Ultrasound-Guided Biceps Femoris Short Head Block in Knee Osteoarthritis (OA) and Postoperative Pain, sponsored by Antalya Training and Research Hospital. Not yet recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-09-04.
Sponsored by Antalya Training and Research Hospital · Not applicable, Interventional, and Treatment
Total knee arthroplasty (TKA) is frequently associated with moderate to severe postoperative pain, which may delay mobilization, increase opioid consumption, and impair functional recovery. Ultrasound-guided adductor canal block (ACB) is widely used as part of multimodal analgesia because it provides effective analgesia while preserving quadriceps muscle strength. However, ACB alone may provide insufficient analgesia for the posterior aspect of the knee. The biceps femoris short head (BiFeS) block is a novel ultrasound-guided regional anesthesia technique targeting the posterolateral sensory innervation of the knee and may enhance postoperative analgesia when combined with ACB. However, clinical evidence regarding its analgesic efficacy in patients undergoing total knee arthroplasty remains limited. This prospective, randomized, controlled trial aims to compare postoperative analgesia between ultrasound-guided adductor canal block alone and adductor canal block combined with a biceps femoris short head block in adult patients undergoing primary total knee arthroplasty under spinal anesthesia. Participants will be randomly assigned in a 1:1 ratio to receive either ACB alone or combined ACB plus BiFeS block. The primary outcome is cumulative opioid consumption during the first 48 postoperative hours. Secondary outcomes include postoperative pain intensity, time to first analgesic request, quadriceps muscle strength, functional recovery, postoperative recovery quality, postoperative nausea and vomiting, patient and surgeon satisfaction, length of hospital stay, and block-related complications.
Background
Total knee arthroplasty (TKA) is the definitive surgical treatment for end-stage knee osteoarthritis and is one of the most frequently performed orthopedic procedures worldwide. Despite advances in multimodal analgesic strategies, postoperative pain following TKA remains a major clinical challenge. Inadequate pain control may delay early mobilization, impair functional recovery, prolong hospitalization, increase opioid consumption, and reduce patient satisfaction. Therefore, optimization of regional anesthesia techniques continues to be an important component of enhanced recovery protocols after TKA.
Ultrasound-guided adductor canal block (ACB) has become a widely accepted motor-sparing regional analgesic technique for TKA because it provides effective analgesia to the anteromedial aspect of the knee while largely preserving quadriceps muscle strength. Nevertheless, the posterior compartment of the knee receives sensory innervation from branches of the sciatic nerve that are not consistently anesthetized by ACB alone. Consequently, residual posterior knee pain remains a common limitation of this technique.
The ultrasound-guided biceps femoris short head (BiFeS) block is a recently described regional anesthesia technique that targets the posterolateral sensory innervation of the knee through deposition of local anesthetic within the fascial plane adjacent to the short head of the biceps femoris muscle. Anatomical and preliminary clinical investigations suggest that this technique may provide additional analgesic coverage of the posterior knee while preserving motor function. However, evidence regarding its clinical efficacy as an adjunct to ACB in patients undergoing primary TKA remains limited.
Study Objectives
The objective of this study is to determine whether the addition of an ultrasound-guided BiFeS block to a standard ultrasound-guided ACB provides superior postoperative analgesia compared with ultrasound-guided ACB alone in patients undergoing primary unilateral TKA under spinal anesthesia.
Study Design
This is a prospective, single-center, parallel-group, randomized controlled clinical trial. Eligible participants will be randomly assigned in a 1:1 ratio to receive either an ultrasound-guided adductor canal block or an ultrasound-guided adductor canal block combined with a biceps femoris short head block before surgery. All patients underwent total knee arthroplasty under single-shot spinal anesthesia with 15 mg of hyperbaric bupivacaine. No periarticular local infiltration analgesia was performed by the surgical team. Postoperatively, all patients received a standardized multimodal analgesic regimen consisting of intravenous paracetamol (1 g) administered every 8 hours. Rescue analgesia consisted of intravenous tramadol (100 mg), which was administered when the Numeric Rating Scale (NRS) pain score was ≥4.
Outcome Assessment
The primary endpoint is cumulative intravenous morphine consumption (mg) from arrival in the post-anesthesia care unit until 48 hours after surgery. Secondary endpoints include postoperative pain intensity assessed using the Numeric Rating Scale (NRS), time to first rescue analgesic administration, quadriceps muscle strength, functional recovery assessed by the Timed Up and Go test and knee range of motion, quality of postoperative recovery (QoR-15), postoperative nausea and vomiting, patient and surgeon satisfaction, length of hospital stay, and block-related adverse events.
Clinical Significance
This study is designed to provide high-quality evidence regarding the potential clinical benefit of incorporating the BiFeS block into contemporary multimodal analgesic protocols for total knee arthroplasty. If the combined regional analgesic approach demonstrates improved postoperative analgesia while preserving motor function, it may represent an effective strategy to facilitate enhanced recovery after surgery and reduce perioperative opioid requirements.
3,292 studies on the registry are indexed under Osteoarthritis, Knee; 623 are open to participants now.
This study's planned enrollment of 122 is above the median of 68 across 2,714 interventional studies indexed under Osteoarthritis, Knee.
Browse Osteoarthritis, Knee studies →Antalya Training and Research Hospital is the lead sponsor of 104 studies on the registry; 12 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.
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.
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.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
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.
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.
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.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
Participants assigned to this arm will receive an ultrasound-guided adductor canal block before the induction of spinal anesthesia for primary unilateral total knee arthroplasty. All regional blocks will be performed according to a standardized study protocol. Perioperative anesthetic management, surgical procedures, and postoperative multimodal analgesia will be standardized for all participants.
Procedure: Ultrasound-Guided Adductor Canal Block
Participants assigned to this arm will receive an ultrasound-guided adductor canal block combined with an ultrasound-guided biceps femoris short head block before spinal anesthesia for primary unilateral total knee arthroplasty. Both regional blocks will be performed according to a standardized study protocol. Perioperative anesthetic management, surgical procedures, and postoperative multimodal analgesic regimens will be standardized for all participants.
Procedure: Ultrasound-Guided Adductor Canal Block · Procedure: Ultrasound-Guided Biceps Femoris Short Head Block
An ultrasound-guided adductor canal block will be performed before the induction of spinal anesthesia using a standardized technique. Following ultrasound identification of the adductor canal, 30 mL of 0.25% bupivacaine will be injected into the adductor canal adjacent to the femoral artery to provide perioperative analgesia for primary unilateral total knee arthroplasty.
An ultrasound-guided biceps femoris short head block will be performed before the induction of spinal anesthesia using a standardized technique. Following ultrasound identification of the fascial plane adjacent to the short head of the biceps femoris muscle, 20 mL of 0.25% bupivacaine will be administered to provide additional posterolateral knee analgesia as an adjunct to the adductor canal block.
Cumulative Opioid Consumption
Cumulative opioid consumption during the first 48 postoperative hours, recorded as intravenous morphine equivalent dose (mg).
Time frame: From arrival in the post-anesthesia care unit until 48 hours after surgery
Postoperative Pain Intensity
Postoperative pain intensity will be assessed using the 11-point Numeric Rating Scale (NRS). Scores range from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Pain will be evaluated both at rest and during knee flexion. Lower scores indicate better postoperative analgesia.
Time frame: 4, 8, 12, 24, and 48 hours after surgery
Time to First Rescue Analgesic Administration
Time from completion of surgery to the first administration of rescue analgesic medication, recorded in hours. Longer time intervals indicate prolonged postoperative analgesic effectiveness.
Time frame: During the first 48 postoperative hours
Quadriceps Muscle Strength
Quadriceps muscle strength will be assessed using the Manual Muscle Testing (MMT) Scale, ranging from 0 to 5, where 0 represents no visible muscle contraction and 5 represents normal muscle strength against full resistance. Higher scores indicate greater quadriceps muscle strength.
Time frame: Preoperatively and at 8, 24, and 48 hours after surgery
Functional Mobility
Functional mobility will be evaluated using the Timed Up and Go (TUG) Test. The total time (seconds) required to stand from a seated position, walk 3 meters, turn, return, and sit down will be recorded. Shorter completion times indicate better functional mobility. Participants who were unable to perform the TUG test independently at 24 hours after surgery were withdrawn from the study according to the study protocol.
Time frame: 24 and 48 hours after surgery
Knee Range of Motion
Active knee flexion range of motion will be measured in the supine position using a standard goniometer. The maximum active knee flexion angle will be recorded in degrees.
Time frame: Preoperatively and at 12 and 24 hours after surgery
Quality of Recovery at 24 Hours Assessed Using QoR-15
Recovery quality will be evaluated using the Quality of Recovery-15 (QoR-15) questionnaire. Total scores range from 0 to 150, with higher scores indicating better postoperative recovery.
Time frame: 24 hours after surgery
Postoperative Nausea and Vomiting
The severity of postoperative nausea and vomiting will be assessed using a 4-point ordinal scale (0-3), where 0 = none, 1 = mild, 2 = moderate, and 3 = severe. Lower scores indicate fewer postoperative symptoms.
Time frame: Incidence of postopereative nausea and/ or vomiting within 48 hours
Patient Satisfaction
Patient satisfaction with postoperative pain management will be assessed using a 5-point Likert scale, ranging from 1 (very dissatisfied) to 5 (very satisfied). Higher scores indicate greater patient satisfaction.
Time frame: 48 hours after surgery
Surgeon Satisfaction
Surgeon satisfaction with perioperative conditions will be assessed using a 5-point Likert scale, ranging from 1 (very dissatisfied) to 5 (very satisfied). Higher scores indicate greater surgeon satisfaction.
Time frame: At completion of surgery
Length of Hospital Stay
Length of hospital stay will be defined as the time from completion of surgery until hospital discharge and will be recorded in hours. Shorter hospital stay indicates earlier postoperative recovery.
Time frame: From end of surgery to hospital discharge, assessed up to 10 days
Block-Related Adverse Events
The incidence of block-related adverse events, including neurological injury, foot drop, local anesthetic systemic toxicity, hematoma, infection, allergic reactions, and myotoxicity, will be recorded. Outcomes will be reported as the number of participants experiencing each event.
Time frame: From block placement to hospital discharge, assessed up to 10 days
Plan to share: No
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Antalya Training and Research Hospital →