An observational study in Anterior Cruciate Ligament (ACL) Tear, sponsored by Arthroresearch LLC. Not yet recruiting at 1 site in United States. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-07-07.
Sponsored by Arthroresearch LLC · Observational
The goal of this observational study is to learn whether the Robotic Knee Testing system can measure knee looseness in adults with an anterior cruciate ligament, or ACL, tear.
The main question it aims to answer is whether measurements from the Robotic Knee Testing system are related to the doctor's pivot shift exam grade.
Participants will complete one study visit before ACL reconstruction. During the visit, both knees will be tested in the Robotic Knee Testing system. Researchers may also review existing medical information and imaging.
This study includes two parts. In Phase 1, researchers will adjust the Robotic Knee Testing system settings to identify testing conditions that are safe, tolerable, and able to reproduce knee motion similar to the pivot shift exam.
During Phase 1, the device will test how knee motion changes when the leg is placed in different positions. Researchers will evaluate whether tibial internal rotation and knee flexion angle change varus-valgus knee motion. They will also evaluate whether varus-valgus knee position and knee flexion angle change internal-external tibial rotation. These tests are intended to help identify device settings that may reproduce the coupled motion seen during a clinical pivot shift exam.
The robotic torque-motion curves will also be reviewed for abrupt changes, discontinuities, or "jumps." These findings may represent the knee moving from a stable position into an unstable position.
In Phase 2, participants will be tested using the finalized device settings from Phase 1. The device will apply controlled anterior-posterior, internal-external rotation, and varus-valgus movements while measuring knee motion in six degrees of freedom. Researchers will compare the robotic measurements with the pivot shift grade documented by the treating orthopedic surgeon.
When available, existing MRI or X-ray images may also be reviewed to evaluate whether knee bone structure is related to robotic laxity measurements or pivot shift severity. No additional imaging will be performed for this study.
174 studies on the registry are indexed under Lacerations; 43 are open to participants now.
This study's planned enrollment of 25 is below the median of 100 across 37 observational studies indexed under Lacerations.
Browse Lacerations studies →This is the only study on the registry with Arthroresearch LLC as lead sponsor.
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Study participants will be selected from patients being treated for ACL injury by orthopedic providers in the Atlanta metropolitan area. Participants will generally be identified through orthopedic clinic schedules, clinical referrals, or patients scheduled for ACL reconstruction.
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.
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.
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.
Clinician-graded pivot shift
Clinician-graded pivot shift from 0 to 3, obtained from the treating orthopedic surgeon's preoperative clinical exam and/or examination under anesthesia before ACL reconstruction.
Time frame: Before ACL reconstruction, during the preoperative clinical exam and/or examination under anesthesia.
Association Between RKT Knee Motion Measurements and Clinician-Graded Pivot Shift Grade
Relationship between Robotic Knee Testing measurements of tibiofemoral motion and clinician-graded pivot shift grade from 0 to 3. RKT measurements may include tibial translation and rotation during robotic testing.
Time frame: RKT testing at the preoperative study visit and pivot shift grading before ACL reconstruction
RKT Torque-Motion Hysteresis Curve Features
Torque-displacement and torque-rotation curves from robotic testing will be evaluated for features such as slope changes, curve area, discontinuities, or "jumps" that may reflect knee instability.
Time frame: During RKT testing at the preoperative study visit before ACL reconstruction
Effect of Knee Position on RKT Motion Measurements
RKT measurements will be compared across different testing conditions, including tibial internal rotation angle, varus-valgus knee position, knee flexion angle, and preset torque thresholds, to identify settings associated with pivot-shift-like motion.
Time frame: During RKT testing at the preoperative study visit before ACL reconstruction
Association Between Bone Morphology and Knee Instability Measurements
Existing MRI or X-ray images may be reviewed to assess bone morphology, including posterior tibial slope and femoral-tibial plateau geometry, and compare these measures with RKT measurements and pivot shift grade.
Time frame: Existing imaging reviewed after enrollment and before data analysis
Plan to share: No
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This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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