Limb Occlusion PressureLOPNCT04390425
Limb Occlusion Pressure Tourniquets to Decrease Pain After Surgery
A study testing Experimental - Limb Occlusion pressure in people with Limb Occlusion Pressure, run by The Methodist Hospital Research Institute at 1 site in United States.
Trial summary
Currently a standard tourniquet pressure is used for orthopedic surgeries. High tourniquet pressure had been associated with adverse side effects such as ischemia, muscle weakness, and post operative pain. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Limb Occlusion Pressure
- What is being tested?
- Experimental - Limb Occlusion pressure
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 400 participants
- Where
- 1 siteUnited States
- Study dates
- 6 Apr 2018to Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- The research team will test the central hypothesis that LOP tourniquets will decrease pain and opioid use and improve patients outcomes on healthy adults (above the age of 18) undergoing either open carpal tunnel release, open reduction internal fixation distal radius fracture, cubital tunnel release, trigger finger release, thumb CMC arthroplasty, anterior cruciate ligament reconstruction, or total knee replacements
Who cannot join
- Prescription pain medications for chronic conditions (> 6 weeks)
- Patients who cannot use a tourniquet:( ex. Certain patients with fistulas or PVD, certain patient with Peripheral Vascular Disease)
- Prior trauma or surgery to the observed limb.
- Hypotension or hypertension that prevents accurate distal photoplenthysmography probe reading.
Trial locations and contacts
1 site in 1 country.
About this study
Currently a standard tourniquet pressure is used for orthopedic surgeries. High tourniquet pressure had been associated with adverse side effects such as ischemia, muscle weakness, and post operative pain. Limb Occlusion Pressure, LOP, is based off the patient's systolic blood pressure plus a safety margin and is typically much lower than standard tourniquet pressure. The aim of this study is to determine if using LOP during orthopedic surgeries decreases post-operative pain and opioid consumption and improves patient's outcomes.
Read the detailed description
The study will start for each subject in the clinic setting during a standard pre-operative office visit. Consent for the study will be obtained after explaining all aspects of the study. The subjects will be randomly separated into two groups. Half of the subjects will have their procedure performed under standard tourniquet pressure, and the other half of the subjects will have their procedure performed with a distal photoplenthysmography probe that will calculate Limb Occlusion Pressure and inflate the tourniquet to the calculated Limb Occlusion Pressure. The subject will undergo their scheduled procedure in the operating room. The subject will also keep a daily pain and opioid consumption diary at home for two weeks after the surgery. The subject will complete patient outcome questionnaires before the surgery, two weeks after the operation, and 8 weeks after the operation to assess patient outcomes. The subject can complete the questionnaires at home, but if they do not, they will have the option to fill the out during their clinic visits. The patient's pre and post OP questionaries' will be the indicators for patient outcomes. All of the standardized questionnaires give calculated scores based off the patients' responses. As the subject improves their score will increase.The research team can compare change in score between the two groups and change with in groups to access patient outcomes.
To maintain the double blind nature of the study, the tourniquet will be placed, inflated, and draped over before the surgeon enters the operating room. Someone else on the research team, one of the coordinators or one of the residents will record the patients' systolic blood pressure and cuff pressure of the tourniquet before the attending enters the OR. This way the surgeon is still blind to the cuff pressure technique used, LOP or STP, when they rate the quality of the bloodless field after the surgery using a VAS scale.
All of these documents are attached on the summary page under additional documents on the Psycho-Physiological Testing page under number 1. List all the measures/instruments that will be used for this study. The VAS pain and opioid consumption diary is titled LOP pain diary cover page and LOP pain diary. The questionnaires that will be used are DASH, IKDC Subject Knee Evaluation Form, KOOS Junior, KOOS Lysholm, Marx, Michigan Hand Outcomes, Patient Rated Wrist Evaluation, Promis Bank v 1.2 Physical Function, PROMIS SF v 1.1 Global Health, and Tegner Activity Level Scale.
- Conditions
- Limb Occlusion Pressure
- Being tested
- Experimental - Limb Occlusion pressure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Experimental - Limb Occlusion pressureDevice
This intervention involves lower tourniquet pressure than the standard of care. There is no change to tourniquet time or how the surgery is performed.
| Study group | Role | What they receive |
|---|---|---|
| Control - Standard pneumatic tourniquet pressure | No intervention | This group receives the standard pneumatic tourniquet pressure during surgery like they would during standard of care. |
| Experimental - Limb occlusion pressure | Experimental | This group receives a slightly lower tourniquet pressure than they would during standard of care. This lowered limb occlusion pressure is determined by the tourniquet device. Receives: Device: Experimental - Limb Occlusion pressure |
What is being measured
The primary outcome is the main question the study is designed to answer.
Postoperative surgical site pain
Visual analog scale from 0 (no pain) to 10 (worst pain imaginable)
Measured: Pain will be recorded as an average of three reported VAS recordings throughout each day for 14-days following surgery. Will compare change in average pain relative baseline pre-op (0) (within group) at each day post-surgery for 14 days
Postoperative tourniquet site pain
Visual analog scale from 0 (no pain) to 10 (worst pain imaginable)
Measured: Pain will be recorded as an average of three reported VAS recordings throughout each day for 14-days following surgery. Will compare change in average pain relative baseline pre-op (0) (within group) at each day post-surgery for 14 days
Secondary outcomes (1)
Postoperative opioid usage
Patients record the name of the opioid, dosage, and number of pills taken. These are standardized using the morphine milligram equivalents formula.
Measured: Once a day, every day for 2 weeks postoperatively
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 May 2020
- Study start6 Apr 2018
- Primary completion28 Jul 2025
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Limb Occlusion PressureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- There are two groups for this study. The control group receives standard pneumatic tourniquet pressure and the experimental group receives limb occlusion pressure. It is randomized and double-blinded.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 400 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The Methodist Hospital Research Institute
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Shari Liberman, The Methodist Hospital Research Institute
- Investigators
- Patrick McCulloch, MD, Principal investigator, The Methodist Hospital Research Institute
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04390425
- Sponsor's protocol ID
- Pro00018544
- Acronym
- LOP
- Status last verified
- Mar 2026
- First submitted
- 11 May 2020
- Last updated
- 1 Apr 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Publications
Aflatooni J, Goble H, Lambert B, Liberman S, McCulloch PC. Limb Occlusion Pressure Versus Standard Pneumatic Tourniquet Pressure in Anterior Cruciate Ligament Surgery: A Randomized Controlled Trial. J Am Acad Orthop Surg Glob Res Rev. 2025 Apr 30;9(5):e24.00282. doi: 10.5435/JAAOSGlobal-D-24-00282. eCollection 2025 May 1.
PubMed 40326965
Study at a glance
From the registry record, last updated by the sponsor on 1 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Limb Occlusion Pressure Tourniquets to Decrease Pain After Surgery
- ClinicalTrials.gov ID
- NCT04390425
- Acronym / sponsor ID
- LOP / Pro00018544
- Conditions
- Limb Occlusion Pressure
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 400 participants (estimated)
- Lead sponsor
- The Methodist Hospital Research InstituteUniversity, hospital or other
- Study start
- 6 Apr 2018 (actual)
- Primary completion
- 28 Jul 2025 (actual)
- Study completion
- Dec 2026 (estimated)
- First posted
- 15 May 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Currently a standard tourniquet pressure is used for orthopedic surgeries. High tourniquet pressure had been associated with adverse side effects such as ischemia, muscle weakness, and post operative pain. Limb Occlusion Pressure, LOP, is based off the patient's systolic blood pressure plus a safety margin and is typically much lower than standard tourniquet pressure. The aim of this study is to determine if using LOP during orthopedic surgeries decreases post-operative pain and opioid consumption and improves patient's outcomes.
Detailed description
The study will start for each subject in the clinic setting during a standard pre-operative office visit. Consent for the study will be obtained after explaining all aspects of the study. The subjects will be randomly separated into two groups. Half of the subjects will have their procedure performed under standard tourniquet pressure, and the other half of the subjects will have their procedure performed with a distal photoplenthysmography probe that will calculate Limb Occlusion Pressure and inflate the tourniquet to the calculated Limb Occlusion Pressure. The subject will undergo their scheduled procedure in the operating room. The subject will also keep a daily pain and opioid consumption diary at home for two weeks after the surgery. The subject will complete patient outcome questionnaires before the surgery, two weeks after the operation, and 8 weeks after the operation to assess patient outcomes. The subject can complete the questionnaires at home, but if they do not, they will have the option to fill the out during their clinic visits. The patient's pre and post OP questionaries' will be the indicators for patient outcomes. All of the standardized questionnaires give calculated scores based off the patients' responses. As the subject improves their score will increase.The research team can compare change in score between the two groups and change with in groups to access patient outcomes.
To maintain the double blind nature of the study, the tourniquet will be placed, inflated, and draped over before the surgeon enters the operating room. Someone else on the research team, one of the coordinators or one of the residents will record the patients' systolic blood pressure and cuff pressure of the tourniquet before the attending enters the OR. This way the surgeon is still blind to the cuff pressure technique used, LOP or STP, when they rate the quality of the bloodless field after the surgery using a VAS scale.
All of these documents are attached on the summary page under additional documents on the Psycho-Physiological Testing page under number 1. List all the measures/instruments that will be used for this study. The VAS pain and opioid consumption diary is titled LOP pain diary cover page and LOP pain diary. The questionnaires that will be used are DASH, IKDC Subject Knee Evaluation Form, KOOS Junior, KOOS Lysholm, Marx, Michigan Hand Outcomes, Patient Rated Wrist Evaluation, Promis Bank v 1.2 Physical Function, PROMIS SF v 1.1 Global Health, and Tegner Activity Level Scale.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- There are two groups for this study. The control group receives standard pneumatic tourniquet pressure and the experimental group receives limb occlusion pressure. It is randomized and double-blinded.
| Arm | Type | Receives |
|---|---|---|
| Control - Standard pneumatic tourniquet pressure | No intervention | –This group receives the standard pneumatic tourniquet pressure during surgery like they would during standard of care. |
| Experimental - Limb occlusion pressure | Experimental | Device: Experimental - Limb Occlusion pressureThis group receives a slightly lower tourniquet pressure than they would during standard of care. This lowered limb occlusion pressure is determined by the tourniquet device. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- The research team will test the central hypothesis that LOP tourniquets will decrease pain and opioid use and improve patients outcomes on healthy adults (above the age of 18) undergoing either open carpal tunnel release, open reduction internal fixation distal radius fracture, cubital tunnel release, trigger finger release, thumb CMC arthroplasty, anterior cruciate ligament reconstruction, or total knee replacements
Key exclusion criteria (4 listed)
- Prescription pain medications for chronic conditions (> 6 weeks)
- Patients who cannot use a tourniquet:( ex. Certain patients with fistulas or PVD, certain patient with Peripheral Vascular Disease)
- Prior trauma or surgery to the observed limb.
- Hypotension or hypertension that prevents accurate distal photoplenthysmography probe reading.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Experimental - Limb Occlusion pressureThis intervention involves lower tourniquet pressure than the standard of care. There is no change to tourniquet time or how the surgery is performed. | Device | Experimental - Limb occlusion pressure |
Primary outcome
Postoperative surgical site pain
Time frame: Pain will be recorded as an average of three reported VAS recordings throughout each day for 14-days following surgery. Will compare change in average pain relative baseline pre-op (0) (within group) at each day post-surgery for 14 days
Visual analog scale from 0 (no pain) to 10 (worst pain imaginable)
Postoperative tourniquet site pain
Time frame: Pain will be recorded as an average of three reported VAS recordings throughout each day for 14-days following surgery. Will compare change in average pain relative baseline pre-op (0) (within group) at each day post-surgery for 14 days
Visual analog scale from 0 (no pain) to 10 (worst pain imaginable)
1 secondary outcome
Postoperative opioid usage
Time frame: Once a day, every day for 2 weeks postoperatively
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Apr 2026.
- Derived from this study: PubMed 40326965Aflatooni J, Goble H, Lambert B, Liberman S, McCulloch PC. Limb Occlusion Pressure Versus Standard Pneumatic Tourniquet Pressure in Anterior Cruciate Ligament Surgery: A Randomized Controlled Trial. J Am Acad Orthop Surg Glob Res Rev. 2025 Apr 30;9(5):e24.00282. doi: 10.5435/JAAOSGlobal-D-24-00282. eCollection 2025 May 1.
- Individual participant dataSharing planned: No
Related trials for Limb Occlusion Pressure
Not yet recruiting
Blood Flow Restriction Training for Mechanically Ventilated Patients With ICU-Acquired Weakness
Intensive Care Unit Acquired Weakness
Active, not recruiting
Hemodynamic Parameters in People With Atherosclerotic Vascular Disease Referred to a Secondary Prevention and Cardiovascular Rehabilitation Program
Peripheral Artery Disease (PAD), Coronary Artery Disease (CAD) (E.G., Angina, Myocardial Infarction, and Atherosclerotic Heart Disease (ASHD))
Not yet recruiting
Blood Flow Restriction Parameters and Lower Limb Function in Older Adults With Dynapenia
Dynapenia
Active, not recruiting
Surgical Field Quality Assessment and Complications in Distal Radius Fractures Using the Minimum Inflation Tourniquet Pressure.
Distal Radius Fracture
Recruiting
Continuous Compartment Pressure Monitoring for Compartment Syndrome in VA-ECMO Patients
Compartment Syndrome of Leg, Extracorporeal Membrane Oxygenation Complication
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Patrick McCulloch, MD principal investigator
The Methodist Hospital Research Institute
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Experimental - Limb Occlusion pressure in people with Limb Occlusion Pressure, run by The Methodist Hospital Research Institute at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 1 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Postoperative surgical site pain (time frame: Pain will be recorded as an average of three reported VAS recordings throughout each day for 14-days following surgery. Will compare change in average pain relative baseline pre-op (0) (within group) at each day post-surgery for 14 days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04390425, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Apr 2026.